Metadata-Version: 1.1
Name: atila
Version: 0.8.3.7
Summary: Atila Framework
Home-page: https://gitlab.com/hansroh/atila
Author: Hans Roh
Author-email: hansroh@gmail.com
License: MIT
Download-URL: https://pypi.python.org/pypi/atila
Description: Atila
        ===========
        
        *Atila* is simple and minimal framework integrated with `Skitai App Engine`_.
        It is the easiest way to make backend API services.
        
        .. code:: python
        
          # serve.py
        
          import atila
        
          app = atila.Atila (__name__)
        
          @app.route ("/")
          def index (was):
            return "Hello, World"
        
          if __mame__ == "__main__":
            import skitai
        
            skitai.mount ("/", app)
            skitai.run (port = 5000)
        
        And run,
        
        .. code:: bash
        
          python3 serve.py
        
        And you can see `Hello, World` at `http://localhost:5000`.
        
        Here's a more practical example:
        
        .. code:: python
        
          @app.route ("/<int:uid>/photos", methods = ["GET", "DELETE", "POST", "OPTIONS"])
          @app.permission_required ()
          def photos (was, uid, **DATA):
            uid = uid == "me" and was.request.JWT ["uid"] or uid
        
            with was.db ("@mydb") as db:
              if was.request.method == "GET":
                rows = db.select ("photo").filter (uid = uid).execute ().fetch ()
                return was.API (rows = rows) # [ {id: 1, ...}, ... ]
        
              elif was.request.method == "DELETE":
                db.delete ("photo").filter (uid = uid).execute ().commit ()
                return was.API ("205 No Content")
        
              elif was.request.method == "POST":
                if not DATA.get ("title"):
                  raise was.Error ("400 Bad Request", "title required")
                DATA ["uid"] = uid
                row = db.insert ("photo").data (**DATA).returning ("id").execute ().one ()
                return was.API ("201 Created", id = row.id)
        
        .. contents:: Table of Contents
        
        .. _`Skitai App Engine`: https://pypi.org/project/skitai/
        
        
        Important Notice
        =======================
        
        *CAUTION*: Atila is base on WSGI but can be run only
        with `Skitai App Engine`_.
        
        This means if you make your app with Atila, you have no
        choice but Skitai as WSGI app server. And Atila's unique
        and unconventional style may become very hard work to port
        to other framework.
        
        I am currently enjoying to develop both Skitai and Atila,
        but no one can expect future.
        
        So you should think twice before you decide to use this.
        
        
        Installation
        =========================
        
        **Requirements**
        
        Python 3.5+
        PyPy3
        
        **Installation**
        
        Atila and other core base dependent libraries is developing on
        single milestone, install/upgrade all please. Otherwise it is
        highly possible to meet some errors.
        
        With pip
        
        .. code-block:: bash
        
            pip3 install -U atila
        
        With git
        
        .. code-block:: bash
        
            git clone https://gitlab.com/hansroh/atila.git
            cd atila
            pip3 install -e .
        
        
        Core App Options
        ======================================
        
        These are for later quick copying.
        
        **Debug Options**
        
        - debug = False
        - use_reloader = False
        
        **CORS Options**
        
        - access_control_allow_origin = None: list of origin
        - access_control_max_age = 0
        
        **Session/Authenticating Options**
        
        - authenticate = None: basic | digest | bearer
        - securekey = None: string for encrypted session cookie
        - session_timeout = None
        
        **Sub Module Mount Options**
        
        - enable_namespace = True
        
          *Default value has been changed in version 0.7: False -> True*
        
          If you didn't use this option with `True` under version 0.7 you
          may set `False` in version 0.7 for for compatiblity.
        
          Also DO NOT use this option with `False` if not for compatiblity
          reason.
        
        - auto_mount
        
          *Deprecated in version 0.7*
        
          If you call app.mount () or pref.mount (), this option
          will be disabled automatically. Otherwise Atila try to mount
          automatically all sub modules has __mount__ ().
        
        
        Default App Configuration
        =====================================
        
        Below configs are new in version *0.8*.
        
        .. code:: python
        
          app.config.MINIFY_HTML = None | 'strip' | 'minify'
          app.config.JSON_ENCODER = 'utcoffset'
        
        Note: below version 0.8, JSON_ENCODER works as app.config.JSON_ENCODER = 'str'
        which is str (datetime) with system time zone. If you migrate to
        above version 0.8 and you want keep this format, you shoud specify
        app.config.JSON_ENCODER = 'str'.
        
        
        App Examples
        ===========================
        
        You can simply visit `Atila app example`_ for sightseeing.
        
        .. _`Atila app example`: https://gitlab.com/hansroh/atila/tree/master/example
        
        
        Atila with Skitai App Engine
        ====================================
        
        Simple App
        ------------------
        
        .. code:: python
        
          from atila import Atila
          app = Atila(__name__)
        
          ...
        
          @app.route ("/")
          def index (was):
            ...
            return was.response ("200 OK", ...)
        
          if __name__ == "__main__":
            import skitai
        
            with skitai.preference () as pref:
              pref.use_reloader = True
              skitai.mount ('/', './static')
              skitai.mount ('/', app, 'app', pref)
        
            skitai.run ()
        
        If atila app exists seprated file:
        
        .. code:: python
        
          # serve.py
        
          if __name__ == "__main__":
            import skitai
        
            with skitai.preference () as pref:
              pref.use_reloader = True
              skitai.mount ('/', './static')
              skitai.mount ('/', 'myapp/atila_app.py', pref = pref)
            skitai.run ()
        
        Resource Structure For Larger App
        -----------------------------------------------
        
        If your app is simple, it can be made into single app.py
        and templates and static directory.
        
        .. code:: python
        
          from atila import Atila
        
          app = Atila(__name__)
        
          app.use_reloader = True
          app.debug = True
        
          @app.route ("/")
          def index (was):
            ...
            return was.response ("200 OK", ...)
        
          if __name__ == "__main__":
            import skitai
        
            with skitai.preference () as pref:
              pref.use_reloader = True
              skitai.mount ('/', './static')
              skitai.mount ('/', app, 'app', pref)
            skitai.run ()
        
        And run,
        
        .. code:: bash
        
          python3 app.py
        
        But Your app is more bigger, it will be hard to make with single
        app file. Then, you can make services directory to seperate your
        app into several categories.
        
        .. code:: bash
        
          myapp/
            app.py
            services/
            templates/
            resources/
            static/
          serve.py
        
        All sub modules app need, can be placed into services/. services/\*.py
        will be watched for reloading if use_reloader = True.
        
        You can structuring any ways you like and I like this style:
        
        .. code:: bash
        
          services/views.py
          services/apis.py
          services/helpers.py
        
        All modules to mount to app in services, should have def __mount__ (app).
        
        For example, views.py is like this,
        
        .. code:: python
        
          from . import helpers
        
          def __mount__ (app):
            @app.route ("/")
            def index (was):
              ...
              return was.render ("index.html")
        
        Now you just import app decorable moduels at your app.py,
        
        .. code:: python
        
          from atila import Atila
          from services import views, apis
        
          app = Atila(__name__)
        
        That's it.
        
        If app scale is more bigger scale, services can be expanded to sub modules.
        
        .. code:: bash
        
          services/views/index.py, regist.py, search.py, ...
          services/apis/codemap.py,
          services/helpers/utils.py, ...
        
        And import these from app.py,
        
        .. code:: python
        
          from services.views import index, regist, ...
          from services.apis import codemap, ...
        
        Some more other informations will be mentioned at *Mounting Resources*
        section again.
        
        Finally, your server.py:
        
        .. code:: python
        
          import skitai
          with skitai.preference () as pref:
            pref.use_reloader = True
            skitai.mount ('/', './static')
            skitai.mount ('/', 'myapp/app.py', 'app', pref)
          skitai.run ()
        
        Also you can add myapp2, ... and mount them.
        
        
        Request Hanlding with Atila
        ====================================
        
        Runtime App Preference
        -------------------------
        
        **New in skitai version 0.26**
        
        Usally, your app preference setting is like this:
        
        .. code:: python
        
          from atila import Atila
        
          app = Atila(__name__)
        
          app.use_reloader = True
          app.debug = True
          app.config ["prefA"] = 1
          app.config ["prefB"] = 2
        
        Skitai provide runtime preference setting.
        
        .. code:: python
        
          import skitai
        
          with skitai.preference () as pref:
            pref.use_reloader = True
            pref.debug = True
            pref.config ["prefA"] = 1
            pref.config.prefB = 2
            skitai.mount ("/v1", "app_v1/app.py", "app", pref)
          skitai.run ()
        
        Above pref's all properties will be overriden on your app.
        
        Runtime preference can be used with skitai initializing or
        complicated initializing process for your app.
        
        You can create \_\_init\_\_.py at same directory with app.py. And
        bootstrap () function is needed.
        
        \_\_init\_\_.py
        
        .. code:: python
        
          import skitai
          import atila
        
          def bootstrap (pref):
            skitai.register_states ('tbl.test')
        
            with open (pref.config.urlfile, "r") as f:
              pref.config.urllist = []
              while 1:
                line = f.readline ().strip ()
                if not line: break
                pref.config.urllist.append (line.split ("  ", 4))
        
        
        More About Atila App Initialization
        ```````````````````````````````````````
        
        *Note*: There'are two important things for app.\_\_init\_\_.
        
        - add skitai.register_states () if you need state management.
          Inter process state sharing objects should be defined before
          running Skitai.
        
        
        Access Atila App
        ------------------
        
        You can access all Atila object from was.app.
        
        - was.app.debug
        - was.app.use_reloader
        - was.app.config # use for custom configuration like
        - was.app.config.my_setting = 1
        
        - was.app.securekey
        - was.app.session_timeout = None
        
        - was.app.authorization = "digest"
        - was.app.authenticate = False
        - was.app.realm = None
        - was.app.users = {}
        - was.app.jinja_env
        
        - was.app.build_url () is equal to was.urlfor ()
        
        Currently was.app.config has these properties and you can
        reconfig by setting new value:
        
        - was.app.config.max_post_body_size = 5 * 1024 * 1024
        - was.app.config.max_cache_size = 5 * 1024 * 1024
        - was.app.config.max_multipart_body_size = 20 * 1024 * 1024
        - was.app.config.max_upload_file_size = 20000000
        
        
        Debugging and Reloading App
        -----------------------------
        
        If debug is True, all errors even server errors is shown on
        both web browser and console window, otherhwise shown only on console.
        
        If use_reloader is True, Atila will detect file changes and reload
        app automatically, otherwise app will never be reloaded.
        
        .. code:: python
        
          from atila import Atila
        
          app = Atila (__name__)
          app.debug = True # output exception information
          app.use_reloader = True # auto realod on file changed
        
        
        Kill Switch
        ````````````````
        
        Please see, `--devel`_ and `--silent`_ options of Skitai App Engine.
        
        .. _`--devel`: https://pypi.org/project/skitai/#run-as-development-mode
        .. _`--silent`: https://pypi.org/project/skitai/#run-as-silent-mode
        
        
        Routing
        ----------
        
        Basic routing is like this:
        
        .. code:: python
        
          @app.route ("/hello")
          def hello_world (was):
            return was.render ("hello.htm")
        
        For adding some restrictions:
        
        .. code:: python
        
          @app.route ("/hello", methods = ["GET"], content_types = ["text/xml"])
          def hello_world (was):
            return was.render ("hello.htm")
        
        And you can specifyt multiple routing,
        
        .. code:: python
        
          @app.route ("/hello", mehotd = ["POST"])
          @app.route ("/")
          def hello_world (was):
            return was.render ("hello.htm")
        
        If method is not GET, Atila will response http error code 405 (Method
        Not Allowed), and content-type is not text/xml, 415 (Unsupported Content Type).
        
        And here's a notalble routing rule.
        
        .. code:: python
        
          @app.route ("")
          def hello_world (was):
            return was.render ("hello.htm")
        
        This app is mounted to "/sub" on skitai, /sub URL is valid but
        "/sub/" will return 404 code.
        
        On the other hand,
        
        .. code:: python
        
          @app.route ("/")
          def hello_world (was):
            return was.render ("hello.htm")
        
        “/sub” will return 301 code for “/sub/” and “/sub/” is valid URL.
        
        
        Request
        ---------
        
        Reqeust object provides these methods and attributes:
        
        - was.request.method # upper case GET, POST, ...
        - was.request.command # lower case get, post, ...
        - was.request.uri
        - was.request.version # HTTP Version, 1.0, 1.1, 2.0, 3.0
        - was.request.scheme # http or https
        - was.request.headers # case insensitive dictioanry
        - was.request.body # bytes object
        - was.request.args # dictionary merged with url, query string,
          form data and JSON
        - was.request.routed # routed function
        - was.request.routable # {'methods': ["POST", "OPTIONS"],
          'content_types': ["text/xml"], 'options': {...},  'mntopt': {...}}
        - was.request.acceptables # {'text/html': {'q': '0.9'}}
        - was.request.acceptable (media) # check if acceptable media type
          by given media
        - was.request.split_uri () # (script, param, querystring, fragment)
        - was.request.json () # decode request body from JSON
        - was.request.form () # decode request body to dict
          if content-type is form data
        - was.request.dict () # decode request body as dict
          if content-type is compatible with dict - form data or JSON
        - was.request.get_header ("content-type") # case insensitive
        - was.request.get_headers () # retrun header all list
        - was.request.get_body ()
        - was.request.get_scheme () # http or https
        - was.request.get_remote_addr ()
        - was.request.get_user_agent ()
        - was.request.get_content_type ()
        - was.request.get_main_type ()
        - was.request.get_sub_type ()
        
        Getting Parameters
        ---------------------
        
        Atila parameters are comceptually seperated 3 groups: URL, query
        string and body.
        
        Below explaination may be a bit complicated but it is enough to
        remember 3 things:
        
        1. Atila resource parameters can be defined as function arguments
        and use theses native Python function arguments.
        
        2. Also you can access parameter groups by origin:
        
          - was.request.DEFAULT: default arguments of your resource
          - was.request.URL: url query string
          - was.request.FORM
          - was.request.JSON
          - was.request.DATA: automatically choosen one of was.request.FORM
            or was.request.JSON by content-type header of request
          - was.request.ARGS: eventaully was.request.ARGS contains all
            parameters of all origins including was.request.DEFAULT
        
        Getting URL Parameters
        `````````````````````````
        
        URL Parameters should be arguments of resource.
        
        .. code:: python
        
          @app.route ("/episode/<int:id>")
          def episode (was, id):
            return id
          # http://127.0.0.1:5000/episode
        
        for fancy url building, available param types are:
        
        - int: integers and INCLUDING 'me', 'notme' and 'new'
        - path: /download/<int:major_ver>/<path>, should be positioned
          at last like /download/1/version/1.1/win32
        - If not provided, assume as string. and all space will be replaced to "_"
        
        At your template engine, you can access through was.request.PARAMS ["id"].
        
        It is also possible via keywords args,
        
        .. code:: python
        
          @app.route ("/episode/<int:id>")
          def episode (was, \*\*karg):
            retrun was.request.ARGS.get ("id")
          # http://127.0.0.1:5000/episode/100
        
        You can set default value to id,
        
        .. code:: python
        
          @app.route ("/episode/<int:id>", methods = ["GET", "POST", "PUT", "DELETE", "OPTIONS"])
          def episode (was, id = None):
            if was.request.method == "POST" and id is None:
              ...
              return was.API (id = new_id)
            return ...
        
        It makes this URL working,
        
        .. code:: bash
        
          http://127.0.0.1:5000/episode
        
        And was.urlfor will behaive like as below,
        
        .. code:: bash
        
          was.urlfor ("episode")
          >> /episode
        
         was.urlfor ("episode", 100)
          >> /episode/100
        
        *Note* that this does not works for root resource,
        
        .. code:: python
        
          @app.route ("/<int:id>", methods = ["GET", "POST", "PUT", "DELETE", "OPTIONS"])
          def episode (was, id = None):
            if was.request.method == "POST" and id is None:
              ...
              return was.API (id = new_id)
            return ...
        
        By above code, http://127.0.0.1:5000/ will not work. You should define "/" route.
        
        
        
        Query String Parameters
        ``````````````````````````````
        
        qiery string parameter can be both resource arguments but needn't be.
        
        .. code:: python
        
          @app.route ("/hello")
          def hello_world (was, num = 8):
            return num
          # http://127.0.0.1:5000/hello?num=100
        
        It is same as these,
        
        .. code:: python
        
          @app.route ("/hello")
          def hello_world (was):
            return was.request.ARGS.get ("num")
        
          @app.route ("/hello")
          def hello_world (was, **url):
            return url.get ("num")
            # of
            return was.request.URL.get ("num)
        
        Above 2 code blocks have a significant difference. First one can
        get only 'num' parameter. If URL query string contains other
        parameters, Skitai will raise 508 Error. But 2nd one can be any
        parameters.
        
        Getting Form/JSON Parameters
        ```````````````````````````````
        
        Getting form is not different from the way for url parameters, but
        generally form parameters is too many to use with each function
        parameters, can take from single args \*\*form or take mixed with
        named args and \*\*form both.
        
        if request header has application/json
        
        .. code:: python
        
          @app.route ("/hello")
          def hello (was, **form):
            return "Post %s %s" % (form.get ("userid", ""), form.get ("comment", ""))
        
          @app.route ("/hello")
          def hello_world (was, userid, **form):
            return "Post %s %s" % (userid, form.get ("comment", ""))
        
        Note that for receiving request body via arguments, you specify
        keywords args like \*\*karg or specify parameter names of body data.
        
        If you want just handle POST body, you can use was.request.json ()
        or was.request.form () that will return dictionary object.
        
        Getting Composed Parameters
        ```````````````````````````````
        
        You can receive all type of parameters by resource arguments. Let's
        assume yotu resource URL is http://127.0.0.1:5000/episode/100?topic=Python.
        
        .. code:: python
        
          @app.route ("/episode/<int:id>")
          def hello (was, id, topic):
            pass
        
        if URL is http://127.0.0.1:5000/episode/100?topic=Python with Form/JSON
        data {"comment": "It is good idea"}
        
        .. code:: python
        
          @app.route ("/episode/<int:id>")
          def hello (was, id, topic, comment):
            pass
        
        Note that argument should be ordered by:
        
        - URL parameters
        - URL query string
        - Form/JSON body
        
        And note if your request has both query string and form/JSON body,
        and want to receive form paramters via arguments, you should receive
        query string parameters first. It is not allowed to skip query string.
        
        Also you can use keywords argument.
        
        .. code:: python
        
          @app.route ("/episode/<int:id>")
          def hello (was, id, \*\*karg):
            karg.get ('topic')
        
        Note that \*\*karg is contains both query string and form/JSON data
        and no retriction for parameter names.
        
        was.requests.args is merged dictionary for all type of parameters. If
        parameter name is duplicated, its value will be set to form of value
        list (But If parameters exist both URL and form data, form data always
        has priority. It means URL parameter will be ignored).
        
        Then simpletst way for getting parameters, use was.request.args.
        
        
        .. code:: python
        
          @app.route ("/episode/<int:id>")
          def hello (was, id):
            was.request.args.get ('topic')
        
        Testing Parameters
        ```````````````````````````````
        
        For parameter checking,
        
        .. code:: python
        
          @app.route ("/test")
          @app.require ("ARGS", ["id"], ints = ["id"])
          def test (was, id):
            return was.render ("test.html")
        
        'id' is required and sholud be int type.
        
        Spec is,
        
        .. code:: python
        
          @app.require (
            scope, required = None, ints = None, floats = None,
            emails = None, uuids = None, nones = None, lists = None,
            strings = None, booleans = None, dicts = None,
            notags = None, safes = None,
            **kargs
          )
        
        - notags: replace all < and >
        - safes: reject if find XSS possible string
        
        *scope* can be:
        
        - URL
        - FORM
        - JSON
        - ARGS: default, all of above
        
        - GET
        - DELETE
        - PATCH
        - POST
        - PUT
        
        .. code:: python
        
            @app.route ("/1")
            @app.require ("GET", ints = ['offset', 'limit'])
            @app.require ("PUT", ['id'])
            def index6 (was, offset = 0, limit = 10, **DATA):
                assert isinstance (limit, int) # limit converted into int type
                if was.request.method == 'PUT':
                  current = DATA [id]
        
        You can test more detail using kargs.
        
        .. code:: python
        
            @app.route ("/1")
            @app.require ("ARGS", a__gte = 5, b__between = (-4, -1), c__in = (1, 2))
            def index6 (was):
                return ""
        
        - __between
        - __neq
        - __gt, __gte
        - __lt, __lte
        
        Checking parameter with regular expression,
        
        .. code:: python
        
            @app.route ("/2")
            @app.require ("ARGS", a = re.compile ("^hans"))
            def index7 (was):
                return ""
        
        Checking parameter length, use __len:
        
        .. code:: python
        
            @app.route ("/3")
            @app.require ("ARGS", a__len__between = (4, 8))
            def index7 (was):
                return ""
        
        
        Pre-Defined Parameter Values
        ``````````````````````````````````````````````````````
        
        'me', 'notme' is special prameter value used by authentication.
        
        - 'me' can be resolved into user ID on request handling
        - 'notme' can ignore specific user ID for administative
          search purpose, BUT for your safey, 'notme' is allowed
          only with "GET" request
        - 'new' is dummy value especially with "POST" method. But
          it is not restricted by methods. Maybe you can use 'new'
          with 'GET' for getting newlest items.
        
        .. code:: python
        
          @app.route ("/episodes/<int:uid>")
          @app.permission_required (uid = ["staff"])
          def episodes (uid):
            ...
        
        Now paramter 'uid' is bound with permission.
        
        Belows are all valid URI.
        
        - GET /episodes/me, if request user have any permission
        - DELETE /episodes/me if request user have any permission
        - GET /episodes/4, if request user have staff permission,
          else raise 403 error
        - PATCH /episodes/4, if request user have staff permission,
          else raise 403 error
        - GET /episodes/new, if request user have staff permission,
          else raise 403 error
        - POST /episodes/new, if request user have staff permission,
          else raise 403 error
        - GET /episodes/notme, if request user have staff permission,
          else raise 403 error
        
        But belows are all invalid and HTTP 421 error will be raised
        for your safety reason. If these're allowed, there is lot of
        danger delete/update all users (or all rows of database table).
        
        - DELETE /episodes/notme
        - POST /episodes/notme
        - PATCH /episodes/notme
        - PUT /episodes/notme
        
        Obviously, I am sure you already know exact resource ID for
        above tasks.
        
        
        Make Your Own Rule
        ``````````````````````````
        
        The way to get parameters is little messy. But I want to try to
        make more pythonic style. Even all routed method can be called by
        another non app functions.
        
        Initially I want to use like this.
        
        .. code:: python
        
          @app.route ("/pets/<kind>")
          def pets (was, kind, limit, offset = 0, **JSON):
            ...
        
        It can be requested by requests.
        
        .. code:: python
        
          requests.post (
            "http://localhost/pets/dog?limit=10",
            json = {"area": "LA"}
          )
        
        If you need to check the origin of parameters, require decorator
        is useful.
        
        .. code:: python
        
          @app.route ("/pets/<kind>")
          @app.require ("JSON", ["area"])
          def pets (was, kind, limit, offset = 0, **JSON):
            ...
        
        That's just my opinion.
        
        
        Response
        -------------
        
        Basically, just return contents.
        
        .. code:: python
        
          @app.route ("/hello")
          def hello_world (was):
            return was.render ("hello.htm")
        
        If you need set additional headers or HTTP status,
        
        .. code:: python
        
          @app.route ("/hello")
          def hello (was):
            return was.response ("200 OK", was.render ("hello.htm"), [("Cache-Control", "max-age=60")])
        
          def hello (was):
            return was.response (
              body = was.render ("hello.htm"),
              headers = [("Cache-Control", "max-age=60")]
            )
        
          def hello (was):
            was.response.set_header ("Cache-Control", "max-age=60")
            return was.render ("hello.htm")
        
        Above 3 examples will make exacltly same result.
        
        Sending specific HTTP status code,
        
        .. code:: python
        
          def hello (was):
            return was.response ("404 Not Found", was.render ("err404.htm"))
        
          def hello (was):
            # if body is not given, automaticcally generated with default error template.
            return was.response ("404 Not Found")
        
        If app raise exception, traceback information will be displayed
        only app.debug = True. But you intentionally send it inspite of
        app.debug = False:
        
        .. code:: python
        
          # File
          @app.route ("/raise_exception")
          def raise_exception (was):
            try:
              raise ValueError ("Test Error")
            except:
              return was.response ("500 Internal Server Error", exc_info = sys.exc_info ())
        
        If you use custom error handler, you can set detail explaination
        to error ["detail"].
        
        .. code:: python
        
          @app.default_error_handler
          def default_error_handler (was, error):
            return was.render ("errors/default.html", error = error)
        
          def error (was):
            return was.response.with_explain ('503 Serivce Unavaliable', "Please Visit On Thurse Day")
        
        
        You can return various objects.
        
        .. code:: python
        
          # File
          @app.route ("/streaming")
          def streaming (was):
            return was.response ("200 OK", open ("mypicnic.mp4", "rb"), headers = [("Content-Type", "video/mp4")])
        
          # Generator
          def build_csv (was):
            def generate():
              for row in iter_all_rows():
                yield ','.join(row) + '\n'
            return was.response ("200 OK", generate (), headers = [("Content-Type", "text/csv")])
        
        
        All available return types are:
        
        - String, Bytes, Unicode
        - File-like object has 'read (buffer_size)' method, optional 'close ()'
        - Iterator/Generator object has 'next() or _next()' method, optional
          'close ()' and shoud raise StopIteration if no more data exists.
        - Something object has 'more()' method, optional 'close ()'
        - Classes of skitai.lib.producers
        - List/Tuple contains above objects
        - XMLRPC dumpable object for if you want to response to XMLRPC
        
        The object has 'close ()' method, will be called when all data
        consumed, or socket is disconnected with client by any reasons.
        
        - was.response (status = "200 OK", body = None, headers = None,
          exc_info = None)
        - was.response.throw (status = "200 OK"): abort handling request,
          generated contents and return http error immediatly
        - was.API (\_\_data_dict\_\_ = None, \*\*kargs): return api
          response container
        - was.Fault (status = "200 OK",\*args, \*\*kargs): shortcut for
          was.response (status, was.API (...)) if status code is 2xx
          and was.response (status, was.Fault (...))
        - was.response.traceback (msg = "", code = 10001,  debug = 'see traceback',
          more_info = None):
          return api response container with setting traceback info
        
        - was.response.set_status (status) # "200 OK", "404 Not Found"
        - was.response.get_status ()
        - was.response.set_headers (headers) # [(key, value), ...]
        - was.response.get_headers ()
        - was.response.set_header (k, v)
        - was.response.get_header (k)
        - was.response.del_header (k)
        - was.response.hint_promise (uri) # *New in skitai version 0.16.4*,
          only works with HTTP/2.x and will be ignored HTTP/1.x
        
        
        HTTP Exception
        ``````````````````````````
        
        Abort immediatly and send HTTP eroor content.
        
        .. code:: python
        
          @app.route ("/<filename>")
          def getfile (was, filename):
            if not os.path.isfile (filename):
              raise was.Error ("404 Not Found", "{} not exists".format (filename))
            return was.File (filename)
        
        Using assert, you can quick send *400 Not My Fault*
        
        .. code:: python
        
          @app.route ("/<filename>")
          def getfile (was, filename):
            assert filename.endswith ('.png'), 'filename must be end with png'
            return was.File (filename)
        
        
        File Stream
        `````````````
        
        Response provides some methods for special objects.
        
        First of all, for send a file,
        
        .. code:: python
        
          @app.route ("/<filename>")
          def getfile (was, filename):
            return was.File ('/data/%s' % filename)
        
        
        API Response
        ````````````````````
        *New in skitai version 0.26.15.9*
        
        In cases you want to retrun JSON API reponse,
        
        .. code:: python
        
          # return JSON {data: [1,2,3]}
          return was.Fault ('200 OK', data = [1, 2, 3])
          # return empty JSON {}
          return was.Fault (201 Accept')
        
          # and shortcut if response HTTP status code is 200 OK,
          return was.API (data =  [1, 2, 3])
        
          # return empty JSON {}
          return was.API ()
        
        For sending error response with error information,
        
        .. code:: python
        
          # client will get, {"message": "parameter q required", "code": 10021}
          return was.Fault ('400 Bad Request', 'missing parameter', 10021)
        
          # with additional information,
          was.Fault (
            '400 Bad Request',
            'missing parameter', 10021,
            'need parameter offset and limit', # detailed debug information
            'http://127.0.0.1/moreinfo/10021', # more detail URL something
          )
        
        You can send traceback information for debug purpose like in case
        app.debug = False,
        
        .. code:: python
        
          try:
            do something
          except:
            return was.Fault (
              '500 Internal Server Error',
              'somethig is not valid',
              10022,
              traceback = True
            )
        
          # client see,
          {
            "code": 10001,
            "message": "somethig is not valid",
            "debug": "see traceback",
            "traceback": [
              "name 'aa' is not defined",
              "in file app.py at line 276, function search"
            ]
          }
        
        Important note that this response will return with HTTP 200 OK status.
        If you want return 500 code, just let exception go.
        
        But if your client send header with 'Accept: application/json'
        and app.debug is True, Skitai returns traceback information automatically.
        
        **Datetime Encoding JSON**
        
        .. code:: python
        
          app.config.JSON_ENCODER = 'utcoffset'
        
        - utcoffset: 2030-12-24 15:09:00+00 (default, utc timezone)
        - str: 2030-12-24 15:09:00 (with system timezone)
        - iso: 2030-12-04T15:09:00 (utc timezone)
        - unixepoch: 1582850951.0 (utc timezone)
        - digit: 20301224150900 (utc timezone)
        
        
        Selective Media Response By Accept Header
        `````````````````````````````````````````````````````
        
        If client's `Accept` header contains 'text/html', respond as rendered
        HTML or as JSON/XML API response.
        
        .. code:: python
        
          @app.route ('/')
          def index (was, error):
            return was.render_or_API ("index.html", result = result)
        
        
        Future / Futures Response
        ```````````````````````````````````````````````
        
        * New in version 0.2*
        
        With single thread it will be the problem using was' request services
        with dispatch (), It is almost works as IO blocking situation.
        
        was.Tasks.then () / corequest.then () returns Futures instance for delaying
        response until every awaitable tasks are finished and every future tasks
        will be executed concurrently.
        
        *CAUTIONS:*
        
        1. Futures escape ealry from current requet handling thread pool
           and enter to main  event loop. It means they will make connections
           to targets as possible as they can.
           If hundreds of clients request resource using database/upstream server,
           It will make error on target server like "too manty connection error".
           If you use Futures response, you SHOULD make sure these factors.
        2. Futures might be the most efficient if it satisfy 2 conditions, a
           few simultaneously requesting clients, streaming data is relatively
           small size. Lot of clients will consume
           connection resources fast and large data stream make blanch coroutine
           advantages caused of expensive networking cost.
        3. Then you could consider using was.Tasks first because Tasks
           is within thread pool, it will be limit number of connections
           by number of thread pool.
        
        .. code:: python
        
          def test_futures (app, dbpath):
            @app.route ("/")
            def index (was):
                def response (was, tasks):
                    return was.API (status_code = [task.status_code for task in tasks.dispatch ()])
        
                reqs = [
                    was.get ("@pypi/project/skitai/"),
                    was.get ("@pypi/project/rs4/"),
                    was.db ("@sqlite").execute ('SELECT * FROM stocks WHERE symbol=?', ('RHAT',))
                ]
                return was.Tasks (reqs, timeout = 2).then (response)
        
            app.alias ("@pypi", skitai.PROTO_HTTPS, "pypi.org")
            app.alias ("@sqlite", skitai.DB_SQLITE3, dbpath)
            with app.test_client ("/", confutil.getroot ()) as cli:
                resp = cli.get ("/")
                assert resp.data ['status_code'] == [200, 200, 200]
        
        Note that at callback, Futures is converted into Tasks_. Then you
        can use dispatch, wait, fetch ... things.
        
        .. _Tasks: https://pypi.org/project/skitai/#tasks
        
        
        Another example,
        
        .. code:: python
        
          def test_futures (app, dbpath):
            @app.route ("/")
            def index (was):
                def response (was, tasks):
                    tasks.stock.announcements = tasks [0].fetch ()
                    return was.API (tasks.stock)
        
                stock = was.db ("@sqlite").select (stocks").get ("*").filter (symbol='RHAT').execute ().one ()
                reqs = [was.db ("@sqlite").select (announcements").get ("*").filter (id = stock.id).execute ()]
                return was.Tasks (reqs, stock = stock [0]).then (response)
        
            app.alias ("@pypi", skitai.PROTO_HTTPS, "pypi.org")
            app.alias ("@sqlite", skitai.DB_SQLITE3, dbpath)
            with app.test_client ("/", confutil.getroot ()) as cli:
                resp = cli.get ("/")
                resp.data
        
        Chaining is also possible,
        
        .. code:: python
        
            @app.route ("/")
            def index (was):
                def repond (was, tasks):
                    return was.API (status_code_db = [task.status_code for task in tasks.dispatch ()], b = tasks.b, status_code = tasks.status_code)
        
                def checkdb (was, tasks):
                    reqs = [was.db ("@sqlite").execute ('SELECT * FROM stocks WHERE symbol=?', ('RHAT',))]
                    status_code = [rs.status_code for rs in tasks.dispatch ()]
                    return was.Tasks (reqs, b = tasks.a + 100, status_code = status_code).then (repond)
        
                reqs = [
                    was.get ("@pypi/project/skitai/"),
                    was.get ("@pypi/project/rs4/")
                ]
                return was.Tasks (reqs, a = 100).then (checkdb)
        
            app.alias ("@pypi", skitai.PROTO_HTTPS, "pypi.org")
            app.alias ("@sqlite", skitai.DB_SQLITE3, dbpath)
            with app.test_client ("/", confutil.getroot ()) as cli:
                resp = cli.get ("/")
                resp.data
                >> {'b': 200, 'status_code': [200, 200], 'status_code_db': [200]}
        
        
        Process / Thread Response
        `````````````````````````````````````````
        
        These are very same with Future response.
        
        If you have CPU bound jobs, use was.Process.
        
        .. code:: python
        
          @app.route ('...')
          def foo ():
            def repond (was, task):
                return was.API (result = task.fetch ())
            return was.Process (math.sqrt, 4.0).then (respond)
        
        If you have I/O bound jobs, use was.Thread.
        
        
        Proxypass Response
        ```````````````````````````````````
        
        Skitai's mounted proxypass is higher priority than WSGI app. If you
        want make this to lower  priority, can use was.proxypass.
        
        .. code:: python
        
          @app.route ("/<path:path>")
          def proxy (was, path = None):
            return was.proxypass ("@myupstream", path)
        
        But it is valid only if request method is GET, because it is mainly
        used for building integrated development environment with
        frontend frameworks linke Node.js.
        
        
        Mounting Resources: Making Simpler & Modular App
        -------------------------------------------------------------------
        
        *New in skitai version 0.26.17*
        
        Implicit Mount Services On Your App
        ````````````````````````````````````````````
        
        I already mentioned *App Structure* section, you can split yours views
        and help utilties into services directory.
        
        Assume your application directory structure is like this,
        
        .. code:: bash
        
          templates/*.html
          services/*.py # app library, all modules in this directory will be watched for reloading
          static/images # static files
          static/js
          static/css
        
          app.py # this is starter script
        
        app.py
        
        .. code:: python
        
          from services import auth
        
          app = Atila (__name__)
        
          app.debug = True
          app.use_reloader = True
        
          @app.default_error_handler
          def default_error_handler (was, e):
            return str (e)
        
        services/auth.py
        
        .. code:: python
        
          # shared utility functions used by views
        
          def titlize (s):
            ...
            return s
        
          def __mount__ (app):
            @app.login_handler
            def login_handler (was):
              if was.request.session.get ("username"):
                return
              next_url = not was.request.uri.endswith ("signout") and was.request.uri or ""
              return was.redirect (was.urlfor ("signin", next_url))
        
            @app.route ("/signout")
            def signout (was):
              was.request.session.remove ("username")
              was.request.mbox.push ("Signed out successfully", "success")
              return was.redirect (was.urlfor ('index'))
        
            @app.route ("/signin")
            def signin (was, next_url = None, **form):
              if was.request.args.get ("username"):
                user = auth.authenticate (username = was.request.args ["username"], password = was.request.args ["password"])
                if user:
                  was.request.session.set ("username", was.request.args ["username"])
                  return was.redirect (was.request.args ["next_url"])
                else:
                  was.request.mbox.push ("Invalid User Name or Password", "error", icon = "new_releases")
              return was.render ("sign/signin.html", next_url = next_url or was.urlfor ("index"))
        
        You just import module from services. but *def __mount__ (app)* is core in
        each module. Every modules can have *__mount__ (app)* in *services*, so you
        can split and modulize views and utility functions. __mount__ (app) will be
        automatically executed on starting. If you set app.use_reloader, theses services
        will be automatically reloaded and re-executed on file changing. Also you can
        make global app sharable functions into seperate module like util.py without
        views.
        
        
        Mounting Services With Options
        `````````````````````````````````````````````````
        
        If you need additional options on decorating,
        
        .. code:: python
        
          def __mount__ (app):
            @app.route ("/login")
            def login (was):
              ...
        
        And on app,
        
        .. code:: python
        
          from services import auth
        
          app = Atila (__name__)
          app.mount ('/regist', auth)
        
        Finally, route of login is "/regist/login".
        
        Sometimes function names are duplicated if like you
        import contributed services.
        
        .. code:: python
        
          from services import auth
        
          app = Atila (__name__)
          app.mount ( '/regist', auth, ns = "regist")
        
        Now, you can import iport without name collision. But be careful
        when use was.urlfor () etc.
        
        Note that options should be keyword arguments.
        
        .. code:: python
        
          {{ was.urlfor ("regist.login") }}
        
        If you want to mount only debug environment,
        
        .. code:: python
        
          app.mount (auth, debug_only = True)
        
        If you want to authentify to all services,
        
        .. code:: python
        
          app.mount (auth, authenticate = "bearer")
        
        Currently *reserved arguments* are:
        
        - ns
        - authenticate
        - debug_only
        - point
        
        Your custom options can be accessed by __mntopt__ in your module.
        
        First, mount with redirect option.
        
        .. code:: python
        
            app.mount (auth, redirect = "index")
            # automatically set to auth.__mntopt__ = {"redirect": "index"}
        
        then you can access in auth.py,
        
        .. code:: python
        
            @app.route ("/regist/signout")
            def signout (was):
                was.request.mbox.push ("Signed out successfully", "success")
                return was.redirect (was.urlfor (__mntopt__.get ("redirect", 'index')))
        
        Setup Services
        `````````````````````
        
        all service can also have \_\_setup\_\_ hook.
        
        .. code:: python
        
          # foo.py
          BASE_PATH = '/var'
          def __setup__ (app, mntopt):
            global BASE_PATH
            BASE_PATH = mntopt.get ('base_path', BASE_PATH)
        
          def __mount__ (app):
            ...
        
          # app.py
        
          from services import foo
          from atila import Atila
        
          app = Atila (__name__)
          app.mount ('/', foo, base_path = '/home/ubuntu')
        
        
        Mounting Package
        ````````````````````````
        
        Assume you have examples package in your service.
        
        .. code:: bash
        
          services/examples/__init__.py
          services/examples/foo.py
          services/examples/bar.py
        
        You can use \_\_setup\_\_ hook for mounting all sub services.
        
        .. code:: python
        
          # services/examples/__init__.py
          from . import foo, bar
        
          def __setup__ (app, mntopt):
            app.mount ('/foo', foo, threshold = mntopt.get ('threashold', 5))
            app.mount ('/bar', bar)
        
        Then you can mount just top package one.
        
        .. code:: python
        
            # app.py
            from services import examples
        
            app.mount ('/examples', examples, threshold = 10)
        
        As a result, foo will be mounted on `/examples/foo`.
        
        
        Unmounting Resources
        ```````````````````````````````
        
        *New in skitai version 0.27*
        
        Also 'umount' is avaliable for cleaning up module resource.
        
        .. code:: python
        
          resource = ...
        
          def __umount__ (app):
            resource.close ()
            app.someghing = None
        
        This will be automatically called when:
        
        - before module itself is reloading
        - before app is reloading
        - app unmounted from Skitai
        
        
        More About Namespace
        ````````````````````````````````````
        
        If you develop reusable task modules, pay attention to namespace
        and URL building.
        
        For example, below module is mount with app.mount (auth, ns = "regist").
        
        .. code:: python
        
          # auth.py
        
          def __mount__ (app):
            @app.route ("/func1")
            def func1 (was, a):
              ...
        
            @app.route ("/func2")
            def func2 (was):
              was.urlfor ("func1", "hello")
        
        This was.urlfor ("func1") in func2 might be dangerous, because this task
        modules may have namespace. Then you consider ns like this.
        
        .. code:: python
        
          was.urlfor ("{}func1".format (__mntopt__.get ("ns") and __mntopt__ ["ns"] + "." or ""), , "hello")
        
        But it is not pretty, so you can pretty style,
        
        .. code:: python
        
          @app.route ("/func2")
          def func2 (was):
            was.urlfor (func1, "hello")
        
        *New in version 0.3.3*
        
        If you want to access resources to another sub module, you can use
        with full module name.
        
        For example,
        
        .. code:: python
        
          # services/v1/account.py
          def __mount__ (app):
            @app.route ("/register")
            def register (was):
              ...
        
        An you can access like this,
        
        .. code:: python
        
          was.urlfor ("v1.account.register")
        
        
        More About Websocket
        --------------------------------------
        
        **websocket design specs** can be choosen one of 2.
        
        WS_CHANNEL
        
          - Thread pool manages n websocket connection
          - It's simple request and response way like AJAX
          - Low cost on threads resources, but reposne cost is relatvley
            high than the others
        
        WS_GROUPCHAT (New in version 0.24)
        
          - Thread pool manages n websockets connection
          - Chat room model
        
        **websocket message handling options**
        
        WS_THREAD
        
          - default, function base websocket message handling
          - it treats every single websocket message as single request to
            resources like url requests.
          - on receiving message from client, it will call function
            for handling with queue and thread pool, it is basically
            same as request resource
        
        WS_NOTHREAD
        
          - non-threaded function call base websocket message handling
          - it is faster than WS_THREAD
        
        WS_SESSION (New in version 0.30)
        
          - non-threaded generator base websocket message handling
          - cannot use this option with WS_THREADSAFE
        
        WS_THREADSAFE (New in version 0.26)
        
          - Mostly same as WS_THREAD
          - Message sending is thread safe
          - Most case you needn't this option, but you create yourself one or
            more threads using websocket.send () method you need this for
            your convinience
        
        *Note:* WS_NOTHREAD and WS_SESSION will block SKitai event loop while
        you generate message to respond. If sending messasge generation time is
        reltively long, use WS_THREAD or WS_THREADSAFE.
        
        **message_encoding**
        
        Websocket messages will be automatically converted to theses objects.
        Note that option is only available with Atila WSGI container.
        
          - WS_MSG_JSON
          - WS_MSG_XMLRPC
        
        
        *New in skitai version 0.26.18*
        
        Websokect usage is already explained, but Atila provide @app.websocket
        decorator for more elegant way to use it.
        
        .. code:: python
        
          def onopen (was):
            print ('websocket opened')
        
          def onclose (was):
            print ('websocket closed')
        
          @app.route ("/websocket")
          @app.websocket (skitai.WS_CHANNEL, 1200, onopen, onclose)
          def websocket (was, message):
            return 'you said: ' + message
        
        This decorator spec is,
        
        .. code:: python
        
          @app.websocket (
            spec, # one of skitai.WS_CHANNEL and skitai.WS_GROUPCHAT
            timeout = 60,
            onopen = None,
            onclose = None
          )
        
        In some cases, you need additional parameter for opening/closing websocket.
        
        .. code:: python
        
          @app.route ("/websocket")
          @app.websocket (skitai.WS_CHANNEL | skitai.WS_THREADSAFE, 1200, onopen)
          def websocket (was, message, option):
            return 'you said: ' + message
        
        Then, your onopen function must have additional parameters except *message*.
        
        .. code:: python
        
          def onopen (was):
            print ('websocket opened with', was.request.ARGS ["option"])
        
        Now, your websocket endpoint is "ws://127.0.0.1:5000/websocket?option=value"
        
        
        WS_NOTHREAD
        ````````````````````````
        
        WS_NOTHREAD does not use queue or thread pool. In this case, response is
        more faster but if response includes IO blocking operation, entire
        Skitai event loop will be blocked.
        
        .. code:: python
        
          @app.route ("/websocket")
          @app.websocket (skitai.WS_CHANNEL | skitai.WS_NOTHREAD, 60, onopen)
          def websocket (was, message):
            return 'you said: ' + message
        
        WS_SESSION
        ````````````````````````
        
        With WS_SESSION should return Python generator object,
        
        .. code:: python
        
          @app.route ("/websocket")
            @app.websocket (skitai.WS_CHANNEL | skitai.WS_SESSION, 60)
            def websocket (was):
              while 1:
                message = yield
                if not message:
                  return #strop iterating
                yield "ECHO:" + message
        
        *Note:* If you use WS_SESSION option, onopen and onclose should be None,
        because in session, you can handle open and close within your function.
        
        
        Pushing Message Through Connected Client
        --------------------------------------------------------------
        
        Save websocket client id to session.
        
        .. code:: python
        
          def onopen (was):
            was.request.session.set ("WS_ID", was.websocket.client_id)
        
          def onclose (was):
            was.request.session.remove ("WS_ID")
        
          @app.route ("/websocket")
          @app.websocket (skitai.WS_CHANNEL | skitai.WS_FAST, 1200, onopen, onclose)
          def websocket (was, message):
            return 'you said: ' + message
        
        And push message to client.
        
        .. code:: python
        
          @app.route ("/item_in_stock")
          def item_in_stock (was):
            app.websocket_send (
              was.request.session.get ("WS_ID"),
              "Item In Stock!"
            )
        
        *Note:*: I'm not sure it is works in all web browser.
        
        
        Building URL
        ---------------
        
        If your app is mounted at "/math",
        
        .. code:: python
        
          @app.route ("/add")
          def add (was, num1, num2):
            return int (num1) + int (num2)
        
          was.app.build_url ("add", 10, 40) # returned '/math/add?num1=10&num2=40'
        
          # BUT it's too long to use practically,
          # was.urlfor is acronym for was.app.build_url
          was.urlfor ("add", 10, 40) # returned '/math/add?num1=10&num2=40'
          was.urlfor ("add", 10, num2=60) # returned '/math/add?num1=10&num2=60'
        
          #You can use function directly as well,
          was.urlfor (add, 10, 40) # returned '/math/add?num1=10&num2=40'
        
          @app.route ("/hello/<name>")
          def hello (was, name = "Hans Roh"):
            return "Hello, %s" % name
        
          was.urlfor ("hello", "Your Name") # returned '/math/hello/Your_Name'
        
        Basically, was.urlfor is same as Python function call.
        
        
        Building URL by Updating Parameters Partially
        ````````````````````````````````````````````````
        
        **New in skitai version 0.27**
        
        .. code:: python
        
          @app.route ("/navigate")
          def navigate (was, limit = 20, pageno = 1):
            return ...
        
        If this resource was requested by /naviagte?limit=100&pageno=2, and
        if you want to make new resource url with keep a's value (=100),
        you can make URL like this,
        
        .. code:: python
        
          was.urlfor ("navigate", was.request.args.limit, 3)
        
        But you can update only changed parameters partially,
        
        .. code:: python
        
          was.urlpatch ("add", pageno = 3)
        
        Parameter a's value will be kept with current requested parameters.
        Note that was.urlpatch can be recieved keyword arguments only except
        first resource name.
        
        was.urlpatch is used changing partial parameters (or none) based over
        current parameters.
        
        
        Building Base URL without Parameters
        ````````````````````````````````````
        
        **New in skitai version 0.27**
        
        Sometimes you need to know just resource's base path info - especially
        client-side javascript URL building, then use *was.basepath*.
        
        .. code:: python
        
          @app.route ("/navigate")
          def navigate (was, limit, pageno = 1):
            return ...
        
        .. code:: python
        
          was.basepath ("navigate")
          >> return "/navigate"
        
        For example, in your VueJS template,
        
        .. code:: html
        
          <a :href="'{{ was.basepath ('navigate') }}?limit=' + limit_option + '&pageno=' + (current_page + 1)">Next Page</a>
        
        Note that base path means for fancy Url,
        
        .. code:: python
        
          @app.route ("/user/<id>")
          >> base path is "/user/"
        
          @app.route ("/user/<id>/pat")
          >> base path is "/user/"
        
        
        Access Environment Variables
        ------------------------------
        
        **was.request.env** (*alias: was.env*)
        
        was.request.env is just Python dictionary object.
        
        .. code:: python
        
          if "HTTP_USER_AGENT" in was.request.env:
            ...
          was.request.env.get ("CONTENT_TYPE")
        
        
        Access Cookie
        ----------------
        
        **was.request.cookie** (*alias: was.cookie*)
        
        was.request.cookie has almost dictionary methods.
        
        .. code:: python
        
          if "user_id" not in was.request.cookie:
            was.request.cookie.set ("user_id", "hansroh")
            # or
            was.request.cookie ["user_id"] = "hansroh"
        
        
        *Changed in version 0.15.30*
        
        'was.request.cookie.set()' method prototype has been changed.
        
        .. code:: python
        
          was.request.cookie.set (
            key, val,
            expires = None,
            path = None, domain = None,
            secure = False, http_only = False
          )
        
        'expires' args is seconds to expire.
        
         - if None, this cookie valid until browser closed
         - if 0 or 'now', expired immediately
         - if 'never', expire date will be set to a hundred years from now
        
        If 'secure' and 'http_only' options are set to True, 'Secure' and
        'HttpOnly' parameters will be added to Set-Cookie header.
        
        If 'path' is None, every app's cookie path will be automaticaaly
        set to their mount point.
        
        For example, your admin app is mounted on "/admin" in configuration
        file like this:
        
        .. code:: python
        
          app = ... ()
        
          if __name__ == "__main__":
        
            import skitai
        
            skitai.run (
              address = "127.0.0.1",
              port = 5000,
              mount = {'/admin': app}
            )
        
        If you don't specify cookie path when set, cookie path will be automatically
        set to '/admin'. So you want to access from another apps, cookie should
        be set with upper path = '/'.
        
        .. code:: python
        
          was.request.cookie.set ('private_cookie', val)
        
          was.request.cookie.set ('public_cookie', val, path = '/')
        
        - was.request.cookie.set (key, val, expires = None, path = None,
          domain = None, secure = False, http_only = False)
        - was.request.cookie.remove (key, path, domain)
        - was.request.cookie.clear (path, domain)
        - was.request.cookie.keys ()
        - was.request.cookie.values ()
        - was.request.cookie.items ()
        - was.request.cookie.has_key ()
        
        
        Access Session
        ----------------
        
        **was.request.session** (*alias: was.session*)
        
        Strictly speaking, Atila hasn't got traditional session which some data
        is stored on server side. And it doesn't provide any abstract classes or
        methods for storing.
        
        Ailta's session is just one of cookie value which contains signature
        for checking alternation by any other things except Atila.
        
        was.request.session has almost dictionary methods.
        
        To enable session for app, random string formatted securekey should
        be set for encrypt/decrypt session values.
        
        *WARNING*: `securekey` should be same on all skitai apps at least
        within a virtual hosing group, Otherwise it will be serious disaster.
        
        .. code:: python
        
          app.securekey = "ds8fdsflksdjf9879dsf;?<>Asda"
          app.session_timeout = 1200 # sec
        
          @app.route ("/session")
          def hello_world (was, **form):
            if "login" not in was.request.session:
              was.request.session.set ("user_id", form.get ("hansroh"))
              # or
              was.request.session ["user_id"] = form.get ("hansroh")
        
        If you set, alter or remove session value, session expiry is automatically
        extended by app.session_timeout. But just getting value will not be extended.
        If you extend explicit without altering value, you can use touch() or
        set_expiry(). session.touch() will extend by app.session_timeout.
        session.set_expiry (timeout) will extend by timeout value.
        
        Once you set expiry, session auto extenstion will be disabled until
        expiry time become shoter than new expiry time is calculated by
        app.session_timeout.
        
        - was.request.session.set (key, val)
        - was.request.session.get (key, default = None)
        - was.request.session.source_verified (): If current IP address
          matches with last IP accesss session
        - was.request.session.getv (key, default = None): If not
          source_verified (), return default
        - was.request.session.remove (key)
        - was.request.session.clear ()
        - was.request.session.keys ()
        - was.request.session.values ()
        - was.request.session.items ()
        - was.request.session.has_key ()
        - was.request.session.set_expiry (timeout)
        - was.request.session.touch ()
        - was.request.session.expire ()
        - was.request.session.use_time ()
        - was.request.session.impending (): if session timeout remains 20%
        
        
        Messaging Box
        ----------------
        
        **was.request.mbox** (*alias: was.mbox*)
        
        Like Flask's flash feature, Skitai also provide messaging tool.
        
        .. code:: python
        
          @app.route ("/msg")
          def msg (was):
            was.request.mbox.send ("This is Flash Message", "flash")
            was.request.mbox.send ("This is Alert Message Kept by 60 seconds on every request", "alram", valid = 60)
            return was.redirect (was.urlfor ("showmsg", "Hans Roh"), status = "302 Object Moved")
        
          @app.route ("/showmsg")
          def showmsg (was, name):
            return was.render ("msg.htm", name=name)
        
        A part of msg.htm is like this:
        
        .. code:: html
        
          Messages To {{ name }},
          <ul>
            {% for message_id, category, created, valid, msg, extra in was.request.mbox.get () %}
              <li> {{ mtype }}: {{ msg }}</li>
            {% endfor %}
          </ul>
        
        Default value of valid argument is 0, which means if page called
        was.request.mbox.get() is finished successfully, it is automatically deleted
        from mbox.
        
        But like flash message, if messages are delayed by next request, these
        messages are save into secured cookie value, so delayed/long term valid
        messages size is limited by cookie specificatio. Then shorter and fewer
        messsages would be better as possible.
        
        'was.request.mbox' can be used for general page creation like handling notice,
        alram or error messages consistently. In this case, these messages
        (valid=0) is consumed by current request, there's no particular size
        limitation.
        
        Also note valid argument is 0, it will be shown at next request just one
        time, but inspite of next request is after hundred years, it will be
        shown if browser has cookie values.
        
        .. code:: python
        
          @app.before_request
          def before_request (was):
            if has_new_item ():
              was.request.mbox.send ("New Item Arrived", "notice")
        
          @app.route ("/main")
          def main (was):
            return was.render ("news.htm")
        
        news.htm like this:
        
        .. code:: html
        
          News for {{ was.g.username }},
          <ul>
            {% for mid, category, created, valid, msg, extra in was.request.mbox.get ("notice", "news") %}
              <li class="{{category}}"> {{ msg }}</li>
            {% endfor %}
          </ul>
        
        - was.request.mbox.send (msg, category, valid_seconds, key=val, ...)
        - was.request.mbox.get () return [(message_id, category, created_time,
          valid_seconds, msg, extra_dict)]
        - was.request.mbox.get (category) filtered by category
        - was.request.mbox.get (key, val) filtered by extra_dict
        - was.request.mbox.source_verified (): If current IP address
          matches with last IP accesss mbox
        - was.request.mbox.getv (...) return get () if source_verified ()
        - was.request.mbox.search (key, val): find in extra_dict. if val
          is not given or given None, compare with category name. return
          [message_id, ...]
        - was.request.mbox.remove (message_id)
        
        
        Named Session & Messaging Box
        ------------------------------
        
        *New in skitai version 0.15.30*
        
        You can create multiple named session and mbox objects by mount() methods.
        
        .. code:: python
        
          was.request.session.mount (
            name = None,
            session_timeout = None,
            securekey = None,
            path = None,
            domain = None,
            secure = False,
            http_only = False,
            extend = True
           )
        
          was.request.mbox.mount (
            name = None,
            securekey = None,
            path = None,
            domain = None,
            secure = False,
            http_only = False
          )
        
        For example, your app need isolated session or mbox seperated
        default session for any reasons, can create session named 'ADM'
        and if this session or mbox is valid at only /admin URL.
        
        .. code:: python
        
          @app.route("/")
          def index (was):
            was.request.session.mount ("ADM", path = '/admin')
            was.request.session.set ("admin_login", True)
        
            was.request.mbox.mount ("ADM", path = '/admin')
            was.request.mbox.send ("10 data has been deleted", 'warning')
        
        SECUREKEY_STRING needn't same with app.securekey. And path, domain,
        secure, http_only args is for session cookie, you can mount any
        named sessions or mboxes with upper cookie path and upper cookie
        domain. In other words, to share session or mbox with another apps,
        path should be closer to root (/).
        
        .. code:: python
        
          @app.route("/")
          def index (was):
            was.request.session.mount ("ADM", path = '/')
            was.request.session.set ("admin_login", True)
        
        Above 'ADM' sesion can be accessed by all mounted apps because path is '/'.
        
        Also note was.request.session.mount () is exactly same as mounting default session.
        
        mount() is create named session or mbox if not exists, exists() is
        just check wheather exists named session already.
        
        .. code:: python
        
          if not was.request.session.exists (None):
            return "Your session maybe expired or signed out, please sign in again"
        
          if not was.request.session.exists ("ADM"):
            return "Your admin session maybe expired or signed out, please sign in again"
        
        
        
        File Upload
        ---------------
        
        .. code:: python
        
          FORM = """
            <form enctype="multipart/form-data" method="post">
            <input type="hidden" name="submit-hidden" value="Genious">
            <p></p>What is your name? <input type="text" name="submit-name" value="Hans Roh"></p>
            <p></p>What files are you sending? <br />
            <input type="file" name="file">
            </p>
            <input type="submit" value="Send">
            <input type="reset">
          </form>
          """
        
          @app.route ("/upload")
          def upload (was, *form):
            if was.request.command == "get":
              return FORM
            else:
              file = form.get ("file")
              if file:
                file.save ("d:\\var\\upload", dup = "o") # overwrite
        
        'file' object's attributes are:
        
        - file.path: temporary saved file full path
        - file.name: original file name posted
        - file.size
        - file.mimetype
        - file.save (into, name = None, mkdir = False, dup = "u")
        - file.remove ()
        - file.read ()
        
          * if name is None, used file.name
          * dup:
        
            + u - make unique (default)
            + o - overwrite
        
        
        Using SQL Map with SQLPhile
        ---------------------------------
        
        *New in Version 0.26.13*
        
        SQLPhile_ is SQL generator and can be accessed from was.sql.
        
        was.sql is a instance of sqlphile.SQLPhile.
        
        If you want to use SQL templates, create sub directory 'sqlmaps'
        and place sqlmap files.
        
        .. code:: python
        
          # default engine is skitai.DB_PGSQL and also available skitai.DB_SQLITE3
          # no need call for skitai.DB_PGSQL
          app.setup_sqlphile (skitai.DB_SQLITE3)
        
          @app.route ("/")
          def index (was):
            q = was.sql.select (tbl_'user').get ('id, name').filter (id = 4)
            req = was.db ("@db").execute (q)
            result = req.dispatch ()
        
        *New in skitai version 0.27*
        
        From version 0.27 SQLPhile_ is integrated with PostgreSQL and SQLite3.
        
        .. code:: python
        
            app = Atila (__name__)
            app.setup_sqlphile (skitai.DB_PGSQL)
        
            @app.route ("/")
            def query (was):
              dbo = was.db ("@mypostgres")
              req = dbo.select ("cities").get ("id, name").filter (name__like = "virginia").execute ()
              result = req.dispatch ()
              response = req.dispatch (timeout = 2)
              dbo.insert ("cities").data (name = "New York").execute ().wait_or_throw ("500 Server Error")
        
        
        Please, visit SQLPhile_ for more detail.
        
        .. _SQLPhile: https://pypi.python.org/pypi/sqlphile
        
        
        Registering Per Request Calling Functions
        -------------------------------------------
        
        Method decorators called automatically when each method is
        requested in a app.
        
        .. code:: python
        
          @app.before_request
          def before_request (was):
            if not login ():
              return "Not Authorized"
        
          @app.finish_request
          def finish_request (was):
            was.g.user_id
            was.g.user_status
            ...
        
          @app.failed_request
          def failed_request (was, exc_info):
            was.g.user_id
            was.g.user_status
            ...
        
          @app.teardown_request
          def teardown_request (was):
            was.g.resouce.close ()
            ...
        
          @app.route ("/view-account")
          def view_account (was, userid):
            was.g.user_id = "jerry"
            was.g.user_status = "active"
            was.g.resouce = open ()
            return ...
        
        For this situation, 'was' provide was.g that is empty class instance.
        was.g is valid only in current request. After end of current request.
        
        If view_account is called, Atila execute these sequence:
        
        .. code:: python
        
          try:
            try:
              content = before_request (was)
              if content:
                return content
              content = view_account (was, *args, **karg)
        
            except:
              content = failed_request (was, sys.exc_info ())
              if content is None:
                raise
        
            else:
              finish_request (was)
        
          finally:
            teardown_request (was)
        
          return content
        
        Be attention, failed_request's 2nd arguments is sys.exc_info ().
        Also finish_request and teardown_request (NOT failed_request)
        should return None (or return nothing).
        
        If you handle exception with failed_request (), return custom error
        content, or exception will be reraised and Atila will handle exception.
        
        *New in skitai version 0.14.13*
        
        .. code:: python
        
          @app.failed_request
          def failed_request (was, exc_info):
            # releasing resources
            return was.response (
              "501 Server Error",
              was.render ("err501.htm", msg = "We're sorry but something's going wrong")
            )
        
        Define Autoruns
        --------------------------------
        
        *New in skitai version 0.26.18*
        
        You can make automation for preworks and postworks.
        
        .. code:: python
        
          def pre1 (was):
            ...
        
          def pre2 (was):
            ...
        
          def post1 (was):
            ...
        
          @app.run_before (pre1, pre2)
          @app.run_after (post1)
          def index (was):
            return was.render ('index.html')
        
        @app.run_before can return None or responsable contents for
        aborting all next run_before and main request.
        
        @app.run_after return will be ignored
        
        Define Conditional Prework
        -------------------------------
        
        *New in skitai version 0.26.18*
        
        @app.if~s are conditional executing decorators.
        
        .. code:: python
        
          def reload_config (was, path):
            ...
        
          @app.if_file_modified ('/opt/myapp/config', reload_config, interval = 1)
          def index (was):
            return was.render ('index.html')
        
        @app.if_updated need more explaination.
        
        
        Inter Process Update Notification and Consequences Automation
        ----------------------------------------------------------------
        
        *New in skitai version 0.26.18*
        
        @app.if_updated is related with skitai.register_states (), was.setlu()
        and was.getlu() and these are already explained was cache contorl
        part. And Atila app can use more conviniently.
        
        These're used for mostly inter-process notification protocol.
        
        Before skitai.run (), you should define updatable objects as
        string keys:
        
        .. code:: python
        
          skitai.register_states ("weather-news", ...)
        
        Then one process update object and update time by setlu ().
        
        .. code:: python
        
          @app.route ("/")
          def add_weather (was):
            was.db.execute ("insert into weathers ...")
            was.setlu ("weather-news")
            return ...
        
        This update time stamp will be recorded in shared memory, then all skitai
        worker processes can catch this update by comparing previous last update
        time and automate consequences like refreshing cache.
        
        .. code:: python
        
          def reload_cache (was, key):
            ...
        
          @app.if_updated ('weather-news', reload_cache)
          def index (was):
            return was.render ('index.html')
        
        
        App Lifecycle Hook
        ----------------------
        
        These app life cycle methods will be called by this order,
        
        - before_mount (wac): when app imported on skitai server started
        - mounted (*was*): called first with was (instance of wac)
        - mounted_or_reloaded (*was*): called with was (instance of wac)
        - loop whenever app is reloaded,
        
          - oldapp.before_reload (*was*)
          - newapp.reloaded (*was*)
          - mounted_or_reloaded (*was*): called with was (instance of wac)
        
        - before_umount (*was*): called last with was (instance of wac),
          add shutting down process
        - umounted (wac): when skitai server enter shutdown process
        
        Please note that first arg of startup, reload and shutdown is *wac*
        not *was*. *wac* is Python Class object of 'was', so mainly used
        for sharing Skitai server-wide object via was.object before
        instancelizing to *was*.
        
        .. code:: python
        
          @app.before_mount
          def before_mount (wac):
            logger = wac.logger.get ("app")
            # OR
            logger = wac.logger.make_logger ("login", "daily")
            config = wac.config
            wac.register ("loginengine", SNSLoginEngine (logger))
            wac.register ("searcher", FulltextSearcher (wac.numthreads))
        
          @app.before_reload
          def before_remount (wac):
            wac.loginengine.reset ()
        
          @app.umounted
          def before_umount (wac):
            wac.umounted.close ()
        
            wac.unregister ("loginengine")
            wac.unregister ("searcher")
        
        You can access numthreads, logger, config from wac.
        
        As a result, myobject can be accessed by all your current app
        functions even all other apps mounted on Skitai.
        
        .. code:: python
        
          # app mounted to 'abc.com/register'
          @app.route ("/")
          def index (was):
            was.loginengine.check_user_to ("facebook")
            was.searcher.query ("ipad")
        
          # app mounted to 'def.com/'
          @app.route ("/")
          def index (was):
            was.searcher.query ("news")
        
        *Note:* The way to mount with host, see *'Mounting With Virtual
        Host'* chapter below.
        
        It maybe used like plugin system. If a app which should be mounted
        loads pulgin-like objects, theses can be used by Skitai server
        wide apps via was.object1, was.object2,...
        
        *New in skitai version 0.26*
        
        If you have databases or API servers, and want to create cache object
        on app starting, you can use @app.mounted decorator.
        
        .. code:: python
        
          def create_cache (res):
            d = {}
            for row in res.data:
              d [row.code] = row.name
            app.store.set ('STATENAMES', d)
        
          @app.mounted
          def mounted (was):
            was.db ('@mydb', callback = create_cache).execute ("select code, name from states;")
            # or use REST API
            was.get ('@myapi/v1/states', callback = create_cache)
            # or use RPC
            was.rpc ('@myrpc/rpc2', callback = create_cache).get_states ()
        
          @app.reloaded
          def reloaded (was):
            mounted (was) # same as mounted
        
          @app.before_umount
          def before_umount (was):
            was.delete ('@session/v1/sessions', callback = lambda x: None)
        
        But both are not called by request, you CAN'T use request related
        objects like was.request, was.request.cookie etc. And SHOULD use callback
        because these are executed within Main thread.
        
        
        Login and Permission Helper
        ------------------------------
        
        *New in skitai version 0.26.16*
        
        You can define login & permissoin check handler,
        
        .. code:: python
        
          @app.login_handler
          def login_handler (was):
            if was.request.session.get ("demo_username"):
              return
        
            if was.request.args.get ("username"):
              if not was.verify_csrf ():
                raise was.Error ("400 Bad Request")
        
              if was.request.args.get ("signin"):
                user, level = authenticate (username = was.request.args ["username"], password = was.request.args ["password"])
                if user:
                  was.request.session.set ("demo_username", user)
                  was.request.session.set ("demo_permission", level)
                  return
        
                else:
                  was.request.mbox.send ("Invalid User Name or Password", "error")
            return was.render ("login.html", user_form = forms.DemoUserForm ())
        
          @app.permission_check_handler
          def permission_check_handler (was, perms):
            if was.request.session.get ("demo_permission") in perms:
              raise was.Error ("403 Permission Denied")
        
          @app.staff_member_check_handler
          def staff_check_handler (was):
            if was.request.session.get ("demo_permission") not in ('staff'):
              raise was.Error ("403 Staff Permission Required")
        
        If you are using JWT you can integrate with this, And it
        is replacable instead of app.authorization_required.
        
        .. code:: python
        
          @app.permission_check_handler
          def permission_check_handler (was, perms):
              claims = was.request.JWT
              if "err" in claims: return claims ["err"]
              if not perms:
                return # permit
              for p in claims ["levels"]:
                  if p in perms:
                      return # permit
              raise was.Error ("403 Permission Denied")
        
        And use it for your resources if you need,
        
        .. code:: python
        
          @app.route ("/")
          @app.permission_required (["admin"])
          @app.login_required
          def index (was):
            return "Hello"
        
          @app.staff_member_required
          def index2 (was):
            return "Hello"
        
        If every thing is OK, it *SHOULD return None, not True*.
        
        'clarify_permission' and 'clarify_login' will ignore any raise
        HTTP error but just try run 'permission_check_handler'. You can
        set request.user object if user has permission.
        
        .. code:: python
        
          @app.permission_check_handler
          def permission_check_handler (was, perms):
              claims = was.request.JWT
              if "err" in claims:
                return claims ["err"]
              was.request.user = claims ['uid']
              if not perms:
                return # permit
              raise was.Error ("403 Permission Denied")
        
          @app.clarify_permission # ignore http error on handler
          def index (was):
            if not was.request.user:
              return 'permission denied'
            return 'permission granted'
        
        
        Conditional Permission Control
        ````````````````````````````````````````````````````
        
        *New in version 0.3*
        
        Let's assume you manage permission by user levels: admin,
        staff and user.
        
        .. code:: python
        
          @app.permission_check_handler
          def permission_check_handler (was, perms):
            claims = was.request.JWT
            if "err" in claims:
              return claims ["err"]
        
            if not perms:
              return # permit for anyone who is authorized
            if claims ["level"] == "admin":
              return # premit always
            if "admin" in perms:
              raise was.Error ("403 Permission Denied")
            if "staff" in prems and claims ["level"] != "staff":
                raise was.Error ("403 Permission Denied")
        
        .. code:: python
        
          @app.route ("/animals/<id>")
          @app.permission_required ([], id = ["staff"])
          def animals (was, id = None):
              id = id or was.request.JWT ["userid"]
        
        This resources required any permission for "/animals/" or
        "/animals/me". But '/animals/100' is required 'staff' permission.
        It may make permission control more simpler.
        
        Also you can specify premissions per request methods.
        
        .. code:: python
        
          @app.route ("/animals/<id>", methods = ["POST", "DELETE"])
          @app.permission_required (['user'], id = ["staff"], DELETE = ["admin"])
          def animals (was, id = None):
              id = id or was.request.JWT ["userid"]
        
        This resources required 'user' permission for "/animals/" or "/animals/me".
        '/animals/100' is required 'staff' permission. It may make
        permission control more simpler.
        
        
        Testpassing
        `````````````````````````
        
        Also you can test if user is valid,
        
        .. code:: python
        
          def is_superuser (was):
            if was.user.username not in ('admin', 'root'):
              reutrn was.response ("403 Permission Denied")
        
          @app.testpass_required (is_superuser)
          def modify_profile (was):
            ...
        
        The binded testpass_required function can return,
        
        - True or None: continue request
        - False: response 403 Permission Denied immediately
        - Responsable object: response object immediately
        
        
        Cross Site Request Forgery Token (CSRF Token)
        ------------------------------------------------
        
        *New in skitai version 0.26.16*
        
        At template, insert CSRF Token,
        
        .. code:: html
        
          <form>
          {{ was.csrf_token_input }}
          ...
          </form>
        
        then verify token like this,
        
        .. code:: python
        
          @app.before_request
          def before_request (was):
            if was.request.args.get ("username"):
              if not was.verify_csrf ():
                return was.response ("400 Bad Request")
        
        Or use decorator,
        
        .. code:: python
        
          @app.csrf_verification_required
          def before_request (was):
            ...
        
        
        Making One-Time Token
        --------------------------------------
        
        *New in skitai version 0.26.17*
        
        For creatiing onetime link url, you can convert your data to
        signatured token string.
        
        Note: Like JWT token, this token contains data and decode easily,
        then you should not contain important information like password or
        PIN. This token just make sure contained data is not altered by
        comparing signature which is generated with your app scret key.
        
        .. code:: python
        
          @app.route ('/password-reset')
          def password_reset (was)
            if was.request.args ('username'):
              username = "hans"
              token = was.mkott (username, 3600, "pwrset") # valid within 1 hour
              pw_reset_url = was.urlfor ('reset_password', token)
              # send email
              return was.render ('done.html')
        
            if was.request.args ('token'):
              username = was.deott (was.request.args ['token'])
              if not username:
                return was.response ('400 Bad Request')
              # processing password reset
              ...
        
        If you want to expire token explicit, add session token key
        
        .. code:: python
        
          # valid within 1 hour and create session token named '_reset_token'
          token = was.mkott ("hans", 3600, 'rset')
          >> kO6EYlNE2QLNnospJ+jjOMJjzbw?fXEAKFgGAAAAb2JqZWN0...
        
          username = was.deott (token)
          >> "hans"
        
          # if processing is done and for revoke token,
          was.rvott (token)
        
        
        App Event Handling
        ---------------------
        
        Most of Atila's event handlings are implemented with
        excellent `event-bus`_ library.
        
        *New in skitai version 0.26.16*, *Availabe only on Python 3.5+*
        
        .. code:: python
        
          import atila
        
          @app.on (atila.app_starting)
          def app_starting_handler (wasc):
            print ("I got it!")
        
          @app.on (atila.request_failed)
          def request_failed_handler (was, exc_info):
            print ("I got it!")
        
          @app.on (atila.template_rendering)
          def template_rendering_handler (was, template, params):
            print ("I got it!")
        
        There're some app events.
        
        - atila.app_starting: required (wasc)
        - atila.app_started: required (wasc)
        - atila.app_restarting: required (wasc)
        - atila.app_restarted: required (wasc)
        - atila.app_mounted: required (was)
        - atila.app_unmounting: required (was)
        - atila.request_failed: required ( was, exc_info)
        - atila.request_success: required (was)
        - atila.request_tearing_down: required (was)
        - atila.request_starting: required (was)
        - atila.request_finished: required (was)
        
        .. _`event-bus`: https://pypi.python.org/pypi/event-bus
        
        
        App Storage
        ----------------------------------------
        
        *app.store* object is ditionary like object and provide
        thread-safe accessing.
        
        It SHOULD be simple primitive value like string, int, float.
        About dictionary or class instances, It can't give no guarantee
        for thread-safe.
        
        .. code:: python
        
          def  (was, current_users):
            total = app.store.get ("total-user")
            app.store.set ("total-user", total + 1)
            ...
        
        
        Inverval Base App Maintenancing
        ---------------------------------------------
        
        If you need interval base maintaining jobs,
        
        .. code:: python
        
          app.config.maintain_interval = 10  # seconds
          app.store.set ("num-nodes", 0) # thread safe store
        
          @app.maintain
          def maintain_num_nodes (was, now, count):
            ...
            num_nodes = was.getlu ("cluster.num-nodes")
            if app.store ["num-nodes"] != num_nodes:
              app.store ["num-nodes"] = num_nodes
              app.broadcast ("cluster:num_nodes")
        
        You can add multiple maintain jobs but maintain function
        names is SHOULD be unique.
        
        
        Creating and Handling Custom Event
        ---------------------------------------
        
        *Availabe only on Python 3.5+*
        
        For creating custom event and event handler,
        
        .. code:: python
        
          @app.on ("user-updated")
          def user_updated (was, user):
            ...
        
        For emitting,
        
        .. code:: python
        
          @app.route ('/users', methods = ["POST"])
          def users (was):
            args = was.request.json ()
            ...
        
            app.emit ("user-updated", args ['userid'])
        
            return ''
        
        If event hasn't args, you can use `emit_after` decorator,
        
        .. code:: python
        
          @app.route ('/users', methods = ["POST"])
          @app.emit_after ("user-updated")
          def users (was):
            args = was.request.json ()
            ...
            return ''
        
        Using this, you can build automatic excution chain,
        
        .. code:: python
        
          @app.on ("photo-updated")
          def photo_updated (was):
            ...
        
          @app.on ("user-updated")
          @app.emit_after ("photo-updated")
          def user_updated (was):
            ...
        
          @app.route ('/users', methods = ["POST"])
          @app.emit_after ("user-updated")
          def users (was):
            args = was.request.json ()
            ...
            return ''
        
        
        Cross App Communication & Accessing Resources
        ----------------------------------------------
        
        Skitai prefer spliting apps to small microservices and mount
        them each. This feature make easy to move some of your mounted
        apps move to another machine. But this make difficult to
        communicate between apps.
        
        Here's some helpful solutions.
        
        
        Accessing App Object Properties
        `````````````````````````````````
        
        *New in skitai version 0.26.7.2*
        
        You can mount multiple app on Skitai, and maybe need to another
        app is mounted seperatly.
        
        .. code:: python
        
          skitai.mount ("/", "main.py")
          skitai.mount ("/query", "search.py")
        
        And you can access from filename of app from each apps,
        
        .. code:: python
        
          search_app = was.apps ["search"]
          save_path = search_app.config.save_path
        
        
        URL Building for Resource Accessing
        ````````````````````````````````````
        
        *New in skitai version 0.26.7.2*
        
        If you mount multiple apps like this,
        
        .. code:: python
        
          skitai.mount ("/", "main.py")
          skitai.mount ("/search", "search.py")
        
        For building url in `main.py` app from a query function of
        `search.py` app, you should specify app file name with colon.
        
        .. code:: python
        
          was.urlfor ('search:query', "Your Name") # returned '/search/query?q=Your%20Name'
        
        And this is exactly same as,
        
          was.apps ["search"].build_url ("query", "Your Name")
        
        But this is only functioning between apps are mounted
        within same host.
        
        
        Custom Error Handling
        ``````````````````````````````````````````
        
        *New in skitai version 0.26.7*
        
        .. code:: python
        
          @app.default_error_handler
          def default_error_handler (was, error):
            return "<h1>{code} {message}</h1>".format (**error)
        
        Or you can respond with JSON only.
        
        .. code:: python
        
          @app.error_handler (404)
          def not_found (was, error):
            return "<h1>{code} {message}</h1>".format (**error)
        
        - code: error code
        - message: error message
        - detail: error detail
        - mode: debug or normal
        - debug: debug info
        - time: time when error occured
        - url: request url
        - software: server name and version
        - traceback: available only if app.debug = True or None
        
        Note that custom error templates can not be used before
        routing to the app.
        
        
        Communication with Event
        ``````````````````````````
        
        *New in skitai version 0.26.10*
        *Availabe only on Python 3.5+*
        
        'was' can work as an event bus using app.on_broadcast ()
        - was.broadcast () pair. Let's assume that an users.py app
        handle only user data, and another photo.py app handle only
        photos of users.
        
        .. code:: python
        
          skitai.mount ('/users', 'users.py')
          skitai.mount ('/photos', 'photos.py')
        
        If a user update own profile, sometimes photo information
        should be updated.
        
        At photos.py, you can prepare for listening to 'user:data-added'
        event and this event will be emited from 'was'.
        
        .. code:: python
        
          @app.on_broadcast ('user:data-added')
          def refresh_user_cache (was, userid):
            was.sqlite3 ('@photodb').execute ('update ...').wait ()
        
        and uses.py, you just emit 'user:data-added' event to 'was'.
        
        .. code:: python
        
          @app.route ('/users', methods = ["PATCH"])
          def users (was):
            args = was.request.json ()
            was.sqlite3 ('@userdb').execute ('update ...').wait ()
        
            # broadcasting event to all mounted apps
            was.broadcast ('user:data-added', args ['userid'])
        
            return was.response (
              "200 OK",
              json.dumps ({}),
              [("Content-Type", "application/json")]
            )
        
        If resource always broadcasts event without args, use
        `broadcast_after` decorator.
        
        .. code:: python
        
          @app.broadcast_after ('some-event')
          def users (was):
            args = was.request.json ()
            was.sqlite3 ('@userdb').execute ('update ...').wait ()
        
        Note that this decorator cannot be routed by app.route ().
        
        **CAUTION**: Do not use request specific variables - like request,
        cookie, session and etc in event handler.
        
        
        CORS (Cross Origin Resource Sharing) and Preflight
        -----------------------------------------------------
        
        For allowing CORS, you should do 2 things:
        
        - set app.access_control_allow_origin
        - allow OPTIONS methods for routing
        
        .. code:: python
        
          app = Atila (__name__)
          app.access_control_allow_origin = ["*"]
          # OR specific origins
          app.access_control_allow_origin = ["http://www.skitai.com:5001"]
          app.access_control_max_age = 3600
        
          @app.route ("/post", methods = ["POST", "OPTIONS"])
          def post (was):
            args = was.request.json ()
            return was.jstream ({...})
        
        
        If you want function specific CORS,
        
        .. code:: python
        
          app = Atila (__name__)
        
          @app.route (
           "/post", methods = ["POST", "OPTIONS"],
           access_control_allow_origin = ["http://www.skitai.com:5001"],
           access_control_max_age = 3600
          )
          def post (was):
            args = was.request.json ()
            return was.jstream ({...})
        
        
        WWW-Authenticate
        -------------------
        
        *Changed in version 0.15.21*
        
          - removed app.user and app.password
          - add app.users object has get(username) methods like dictionary
        
        Atila provide simple authenticate for administration or
        perform access control from other system's call.
        
        Authentication On Specific Methods
        `````````````````````````````````````````
        
        Otherwise you can make some routes requirigng authorization
        like this:
        
        .. code:: python
        
          @app.route ("/hello/<name>", authenticate = "digest")
          def hello (was, name = "Hans Roh"):
            return "Hello, %s" % name
        
        Or you can use @app.authorization_required decorator.
        
        .. code:: python
        
          @app.route ("/hello/<name>")
          @app.authorization_required ("digest")
          def hello (was, name = "Hans Roh"):
            return "Hello, %s" % name
        
        Available authorization methods are basic, digest and bearer.
        
        
        Password Provider
        ````````````````````
        
        You can provide password and user information getter by 2 ways.
        
        First, users object
        
        .. code:: python
        
          # users object shoukd have get(username) method
          app.users = {"hansroh": ("1234", False)}
        
        Second, use decorator
        
        .. code:: python
        
          @app.authorization_handler
          def auth_handler (was, username):
            ...
            return ("1234", False)
        
        The return object can be:
        
          - (str password, boolean encrypted, obj userinfo)
          - (str password, boolean encrypted)
          - str password
          - None if authorization failed
        
        If you use encrypted password, you should use digest authorization
        and password should encrypt by this way:
        
        .. code:: python
        
          from hashlib import md5
        
          encrypted_password = md5 (
            ("%s:%s:%s" % (username, realm, password)).encode ("utf8")
          ).hexdigest ()
        
        
        If authorization is successful, app can access username and userinfo
        vi was.request.user.
        
          - was.request.user.name
          - was.request.user.realm
          - was.request.user.info
        
        If your server run with SSL, you can use app.authorization = "basic",
        otherwise recommend using "digest" for your password safety.
        
        Authentication On Entire App
        ```````````````````````````````
        
        For your convinient, you can set authorization requirements to app level.
        
        .. code:: python
        
          app = Atila (__name__)
        
          app.authenticate = "digest"
          app.realm = "Partner App Area of mysite.com"
          app.users = {"app": ("iamyourpartnerapp", 0, {'role': 'root'})}
        
          @app.route ("/hello/<name>")
          def hello (was, name = "Hans Roh"):
            return "Hello, %s" % name
        
        If app.authenticate is set, all routes of app require authorization
        (default is False).
        
        
        (JWT) Bearer Authorization
        --------------------------------------
        
        To making JWT token, your app need securekey.
        
        .. code:: python
        
          app.securekey = '5b2c4f18-01fd-4b85-8cfa-01827878562f'
        
        .. code:: python
        
          was.mkjwt ({"username": "hansroh", "exp": time.time () + 3600, ...})
          >> eyJhbGciOiAiSFMyNTYiLCAidHlwIjogIkpXV...
        
        Note: was.dejwt (token) is also available.
        
        Then client should add 'Authorization' to API request like,
        
        .. code:: python
        
          Authorization: Bearer eyJhbGciOiAiSFMyNTYiLCAidHlwIjogIkpXV...
        
        And use bearer_handler decorators.
        
        .. code:: python
        
          @app.bearer_handler
          def bearer_handler (was, token):
            # if not JWT token,
            claims = parse_your_token_yourself (token)
            # if JWT, just use was.request.JWT
            claims = was.request.JWT
            if "err" in claims:
              return claims ["err"]
        
          @app.route ("/api/v1/predict")
          @app.authorization_required ("bearer")
          def predict (was):
            # now you can use these
            was.request.user # hansroh
            was.request.JWT # dict {"username": "hansroh", "exp": 2900...}
        
        For your convinient, above bearer_handler is registered as
        default handler, but you can still override it.
        
        Implementing XMLRPC Service
        -----------------------------
        
        Client Side:
        
        .. code:: python
        
          import aquests
        
          stub = aquests.rpc ("http://127.0.0.1:5000/rpc")
          stub.add (10000, 5000)
          fetchall ()
        
        Server Side:
        
        .. code:: python
        
          @app.route ("/add")
          def index (was, num1, num2):
            return num1 + num2
        
        Is there nothing to diffrence? Yes. Atila app methods are also
        used for XMLRPC service if return values are XMLRPC dumpable.
        
        
        Implementing gRPC Service
        -----------------------------
        
        Client Side:
        
        .. code:: python
        
          import aquests
          import route_guide_pb2
        
          stub = aquests.grpc ("http://127.0.0.1:5000/routeguide.RouteGuide")
          point = route_guide_pb2.Point (latitude=409146138, longitude=-746188906)
          stub.GetFeature (point)
          aquests.fetchall ()
        
        Server Side:
        
        .. code:: python
        
          import route_guide_pb2
        
          def get_feature (feature_db, point):
            for feature in feature_db:
              if feature.location == point:
                return feature
            return None
        
          @app.route ("/GetFeature")
          def GetFeature (was, point):
            feature = get_feature(db, point)
            if feature is None:
              return route_guide_pb2.Feature(name="", location=point)
            else:
              return feature
        
          if __name__ == "__main__":
        
          skitai.mount = ('/routeguide.RouteGuide', app)
          skitai.urn ()
        
        
        For an example, here's my tfserver_ for Tensor Flow Model Server.
        
        For more about gRPC and route_guide_pb2, go to `gRPC Basics - Python`_.
        
        Note: I think I don't understand about gRPC's stream request and
        response. Does it means chatting style? Why does data stream has
        interval like GPS data be handled as stream type? If it is chat style
        stream, is it more efficient that use proto buffer on Websocket protocol?
        In this case, it is even possible collaborating between multiple gRPC
        clients.
        
        .. _`gRPC Basics - Python`: http://www.grpc.io/docs/tutorials/basic/python.html
        .. _tfserver: https://pypi.python.org/pypi/tfserver
        
        
        Logging and Traceback
        ------------------------
        
        .. code:: python
        
          @app.route ("/")
          def sum ():
            was.log ("called index", "info")
            try:
              ...
            except:
              was.log ("exception occured", "error")
              was.traceback ()
            was.log ("done index", "info")
        
        Note inspite of you do not handle exception, all app exceptions will
        be logged automatically by Atila. And it includes app importing and
        reloading exceptions.
        
        - was.log (msg, category = "info")
        - was.traceback (id = "") # id is used as fast searching log line
          for debug, if not given, id will be *Global transaction ID/Local
          transaction ID*
        
        
        Exposing API Specification
        -----------------------------------------
        
        For debugging and helping to write API specification, Atila
        expose all specification of each resources.
        
        .. code:: python
        
          @app.route ("/isitok/<code>/<type>", methods = ["GET", "POST", "PATCH", "OPTIONS"])
          def isitok (was, code, type):
            return was.API (result = "ok")
        
        That will return,
        
        .. code:: python
        
          {"result": "ok"}
        
        If you set like this,
        
        .. code:: python
        
          app.expose_spec = True
        
        Then will be returned with spec,
        
        .. code:: python
        
          {
            "result": "ok",
            "__spec__": {
                'id': 'isitok',
                'routeopt': {
                    'methods': ["GET", "POST", "PATCH", "OPTIONS"],
                    'route': '/isitok/<code>/<type>',
                    'args': ['code', 'type'],
                    'keywords': None,
                    'urlargs': 2,
                    'mntopt': {
                        'module_name': 'services.v1.apis',
                        'point': '/v1/apis'
                    }
                },
                'auth_requirements': [],
                'parameter_requirements': {},
                'doc': None,
                'current_request': {
                    'http_method': 'GET',
                    'http_version': '1.1',
                    'uri': '/v1/apis/isitok'
                }
             }
          }
        
        Note: This will only work at your local machine (IP address
        starts with 127.0.0.).
        
        App Testing
        ---------------------------
        
        For automated test, Atila provide test_client (). Test client
        will just emulate client-server communication.
        
        myapp.py is:
        
        .. code:: python
        
          app = Atila (__name__)
        
          @app.route ("/")
          def index (was):
            return "<h1>something</h1>"
        
          @app.route ("/apis/pets/<int:id>")
          def pets (was, id):
            return was.API ({"id": id, "kind": "dog", "name": "Monk"})
        
          if __name__ == "__main__":
            skitai.mount ("/", app)
            skitai.run (port = 5000)
        
        If you run unittest with pytest, your test script is like this.
        
        .. code:: python
        
          def test_myapp ():
            from myapp import app
        
            with app.test_client ("/", approot = ".") as cli:
              # html request
              resp = cli.get ("/")
              assert "something" in resp.text
        
              # api call
              stub = cli.api ()
              resp = stub.apis.pets (45).get ()
              assert resp.data ["id"] == 45
        
              resp = stub.apis.pets (100).get ()
              assert resp.data ["id"] == 100
        
        Now run pytest.
        
        Above code works fine if your app is composed with single
        file. If your app has sub modules, app will raise relative
        import related error.
        
        ..code:: python
        
          import skitai
          import atila
        
          def test_myapp ():
            with skitai.preference () as pref:
              app = atila.load ("./mayapp/app.py", pref)
        
        If your app is located as your module's export/skitai/__export__.py,
        
        ..code:: python
        
          import your_module
          app = atila.load (your_module, pref)
        
        Now, you are ready to test.
        
        Note: Internal requests like was.get, was.post, was.jsonrpc
        and database engine operations will work with synchronous
        mode and may will be slow.
        
        
        
        VueJS with Skito-Atila
        ==========================
        
        Without Module Bundlers
        ---------------------------------
        
        I recently wrote about `Single File Component Based Website`_.
        
        It is based on `FranckFreiburger/http-vue-loader`_ and I made
        some examplary templates.
        
        .. _`Single File Component Based Website`: https://gitlab.com/hansroh/http-sfc
        .. _`FranckFreiburger/http-vue-loader`: https://github.com/FranckFreiburger/http-vue-loader
        
        
        
        With Bundlers
        -------------------------
        
        I prefer to build VueJS as frontend app and Atila as backend.
        
        Basic project directory stucture is,
        
        project root
        
        - frontend (vue project)
        
          * <dist>
          * <node_modules>
          * <src>
          * <public>
          * package.json
          * vue.config.js
          * ...
        
        - backend
        
          * <services>
          * serve.py
        
        The core line sof serve.py,
        
        .. code:: python
        
          from atila import Atila
          import skitai
          import os
          import sys
          from services import api
        
          app = Atila (__name__)
          app.mount ("/api/v1", api) # for backend API service
        
          @app.route ("/<path:path>")
          def vapp (was, path = None):
              return was.File (skitai.joinpath ("../frontend", "dist", "index.html"), "text/html")
        
          if __name__ == "__main__":
              with skitai.preference () as pref:
                pref.securekey = None
                pref.max_client_body_size = 2 << 32
                pref.access_control_allow_origin = ["127.0.0.1:5000"]
        
                if "---production" not in sys.argv:
                    pref.debug = True
                    pref.use_reloader = True
                    pref.access_control_allow_origin.append ("127.0.0.1:8080")
        
                skitai.mount ("/", app)
                skitai.mount ("/", "../frontend/dist", pref = pref)
              skitai.run (name = "myapp", port = 5000)
        
        This skitai starting script do these things,
        
        - If requested URL is one of atila routes, then routed to it
        - Otherwise all URL is routed to vue SPA (dist/index.html)
        - All static root mounted to frontend/dist directory
          for service compiled js and css by webpack
        
        You can develop vue app by,
        
        .. code:: bash
        
          npm run serve
          # generally use port 8080
        
        And Atila app developing by,
        
        .. code:: bash
        
          python3 ../backend/serve.py
          # use port 5000
        
        Finally,
        
        .. code:: bash
        
          npm run build
          python3 ../backend/serve.py
        
        
        If you interest about thi stuff, you can have reference_
        which I personally build as bolier-plate. But it is just planning stage.
        
        .. _reference: https://gitlab.com/hansroh/skito-vue
        
        
        Working With Jinja2 Template Engine
        ==============================================================
        
        If you want to use Jinja2 template engine, install first.
        
        .. code:: bash
        
          pip3 install -U jinja2
        
        Although You can use any template engine, Skitai provides was.render()
        which uses Jinja2_ template engine. For providing arguments to Jinja2,
        use dictionary or keyword arguments.
        
        .. code:: python
        
          return was.render ("index.html", choice = 2, product = "Apples")
        
          #is same with:
        
          return was.render ("index.html", {"choice": 2, "product": "Apples"})
        
          #BUT CAN'T:
        
          return was.render ("index.html", {"choice": 2}, product = "Apples")
        
        Directory structure sould be:
        
        - /project_home/app.py
        - /project_home/templates/index.html
        
        Within template, you can access `was` and aliases for your convinient.
        
        - was
        - app: alias for was.app which handling request
        - request: alias for was.request
        - response: alias for was.response
        - context: namespace for given keyword arguments (or dictionary keys)
        
        Note that these names cannot ne used as context variable name.
        
        Also available registered with @app.template_global decorator and
        given keyword arguments (or dictionary keys).
        
        .. code:: html
        
          {{ request.cookie.username }} choices item {{ request.ARGS.get ("choice", "N/A") }}.
        
          <a href="{{ was.urlfor ('checkout', context.choice) }}">Proceed</a>
        
        Also 'was.g' is can be useful in case threr're lots
        of render parameters.
        
        .. code:: python
        
          was.g.product = "Apple"
          was.g.howmany = 10
        
          return was.render ("index.html")
        
        And at jinja2 template,
        
        .. code:: html
        
          Checkout for {{ was.g.howmany }} {{ was.g.product }}{{ was.g.howmany > 1 and "s" or ""}}
        
        
        If you want modify Jinja2 envrionment, can through
        was.app.jinja_env object.
        
        .. code:: python
        
          def generate_form_token ():
            ...
        
          was.app.jinja_env.globals['form_token'] = generate_form_token
        
        And this is same as,
        
        .. code:: python
        
          @app.template_global ('form_token')
          def generate_form_token ():
            ...
        
        
        *New in skitai version 0.15.16*
        
        Added new app.jinja_overlay () for easy calling
        app.jinja_env.overlay ().
        
        Recently JS HTML renderers like Vue.js, React.js
        have confilicts  with default jinja mustache variable.
        In this case you mightbe need change it.
        
        .. code:: python
        
          app = Atila (__name__)
          app.debug = True
          app.use_reloader = True
          app.jinja_overlay (
            variable_start_string = "{{",
            variable_end_string = "}}",
            block_start_string = "{%",
            block_end_string = "%}",
            comment_start_string = "{#",
            comment_end_string = "#}",
            line_statement_prefix = "%",
            line_comment_prefix = "%%",
            **kargs # Jinja2 Environment arguments
          )
        
        To add Jinja2 extensions,
        
        .. code:: python
        
          app.add_jinja_ext ('jinja2.ext.i18n')
        
        Currently, Atila use "jinja2.ext.do", "jinja2.ext.loopcontrols" defaultly.
        
        If you want remove extensions,
        
        .. code:: python
        
          app.jinja_overlay (extensions = [])
        
        
        .. _Jinja2: http://jinja.pocoo.org/
        .. _`Vue.js`: https://vuejs.org/
        
        
        Using Skitai Async Requests Services Working With Jinja2 Template
        ---------------------------------------------------------------------------
        If you want to use Jinja2 template engine, install first.
        
        .. code:: bash
        
          pip3 install -U jinja2
        
        Basic usage is here_.
        
        .. _here: https://pypi.org/project/skitai/#skitai-was-services
        
        Async request's benefit will be maximied at your view template
        rather than your controller. At controller, you just fire your
        requests and get responses at your template.
        
        .. code:: python
        
          @app.route ("/")
          @app.login_required
          def intro (was):
            was.g.aa = was.get ("https://example.com/blur/blur")
            was.g.bb = was.get ("https://example.com/blur/blur/more-blur")
            return was.render ('template.html')
        
        Your template,
        
        .. code:: html
        
          {% set response = was.g.aa.dispatch () %}
          {% if response.status == 3 %}
            {{ was.response.throw ("500 Internal Server Error") }}
          {% endif %}
        
          {% if response.status_code == 200 %}
            {% for each in response.data %}
              ...
            {% endfor %}
          {% endif %}
        
        *Available only with Atila*
        
        Shorter version is for dispatch and throw HTTP error,
        
        .. code:: html
        
          {% set response = was.g.aa.dispatch_or_throw ("500 Internal Server Error") %}
        
        
        Registering Global Template Function
        -------------------------------------------------------------
        
        *New in skitai version 0.26.16*
        
        template_global decorator makes a function possible to use
        in your template,
        
        .. code:: python
        
          @app.template_global ("test_global")
          def test (was):
            return ", ".join.(was.request.args.keys ())
        
        At template,
        
        .. code:: html
        
          {{ test_global () }}
        
        Note that all template global function's first parameter
        should be *was*. But when calling, you SHOULDN't give *was*.
        
        
        Registering Jinja2 Filter
        --------------------------------------------------------------
        
        *New in skitai version 0.26.16*
        
        template_filter decorator makes a function possible
        to use in your template,
        
        .. code:: python
        
          @app.template_filter ("reverse")
          def reverse_filter (s):
            return s [::-1]
        
        At template,
        
        .. code:: html
        
          {{ "Hello" | reverse }}
        
        
        Custom Error Template
        --------------------------------------------------------------
        
        *New in skitai version 0.26.7*
        
        .. code:: python
        
          @app.default_error_handler
          def default_error_handler (was, error):
            return was.render ('default.htm', error = error)
        
          @app.error_handler (404)
          def not_found (was, error):
            return was.render ('404.htm', error = error)
        
        Template file 404.html is like this:
        
        .. code:: html
        
          <h1>{{ error.code }} {{ error.message }}</h1>
          <p>{{ error.detail }}</p>
          <hr>
          <div>URL: {{ error.url }}</div>
          <div>Time: {{ error.time }}</div>
        
        Note that custom error templates can not be used before
        routing to the app.
        
        
        Working With Chameleon Template Engine
        ==============================================================
        
        Chameleon_ is an beautiful HTML/XML template engine.
        
        For using this engine you install first.
        
        .. code:: bash
        
            pip3 install -U chameleon
        
        If you save Chameleon template with '.pt' or '.ptal'
        extensions at templates directory, Atila will render
        this template with Chameleon.
        
        .. _Chameleon: : https://pypi.org/project/Chameleon/
        
        
        Working With Django
        ===========================================
        
        *New in skitai version 0.26.15*
        
        I barely use Django, but recently I have opportunity using
        Django and it is very fantastic and especially impressive
        to Django Admin System.
        
        Here are some examples collaborating with Djnago and Atila.
        
        Before it begin, you should mount Django app,
        
        .. code:: python
        
          # mount django admin
          with skitai.preference () as pref:
            pref.use_reloader = True
            pref.use_debug = True
            # '/' mapped with django.admin in urls.py
            skitai.mount ("/admin", 'django/wsgi.py', 'application', pref)
        
          # mount main app
          with skitai.preference () as pref:
            pref.use_reloader = True
            pref.use_debug = True
            skitai.mount ('/', 'app.py', pref = pref)
        
          skitai.run ()
        
        When Django app is mounted, these will be processed.
        
        1. add django project root path will be added to sys.path
        2. app is mounted
        3. database alias (@mydjangoapp) will be created as
           base name of django project root
        
        Using Django Models
        ------------------------------------
        
        You can use also Django models without mount app.
        
        First of all, you should specify django setting with
        alias for django database engine.
        
        .. code:: python
        
          skitai.alias ("@django", skitai.DJANGO, "myapp/settings.py")
        
        Then call django.setup ()  and you can use your models,
        
        .. code:: python
        
          import django
          django.setup () # should call
          from mydjangoapp.photos import models
        
          @app,route ('/django/hello')
          def django_hello (was):
            models.Photo.objects.create (user='Hans Roh', title = 'My Photo')
            result = models.Photo.filter (user='hansroh').order_by ('-create_at')
        
        You can use Django Query Set as SQL generator for
        Skitai's asynchronous query execution. But it has
        some limitations.
        
        - just vaild only select query and prefetch_related ()
        - effetive only to PostgreSQL and SQLite3 (but SQLite3
          dose not support asynchronous execution, so it is practically meaningless)
        
        .. code:: python
        
          from mydjangoapp.photos import models
        
          @app,route ('/hello')
          def django_hello (was):
            query = models.Photo.objects.filter (topic=1).order_by ('title')
            return was.jstream (was.sqlite3 ("@entity").execute (query).dispatch ().data, 'data')
        
        
        How To
        ================
        
        Response All Errors As JSON
        --------------------------------------
        
        .. code:: python
        
          @app.default_error_handler
          def default_error_handler (was, error):
            code = error ["errno"] or str (error ["code"]) + '00'
            return was.Fault (
              error ["message"].lower (), code, None,
              error ["detail"], exc_info = error ["traceback"]
            )
        
        
        Links
        ======
        
        - `GitLab Repository`_
        - Bug Report: `GitLab issues`_
        
        .. _`GitLab Repository`: https://gitlab.com/hansroh/atila
        .. _`GitLab issues`: https://gitlab.com/hansroh/atila/issues
        
        
        Change Log
        ============
        
        - 0.8  (Feb, 2020)
        
          - add *400 Not My Fault* with assert
          - add notags and safes arguments to @app.require
          - now, csrf token uses cookie not session and kept with browser
          - add remove_csrf ()
          - fix corequest cache sync
          - update, config.MINIFY_HTML = None (default) | 'strip' | 'minify'
          - add @app.csrf_verification_required
          - add '@app.clarify_permission' and '@app.clarify_login' decorators
          - add \_\_setup\_\_ hook for service packages.\_\_init\_\_.py
        
        - 0.7 (Dec, 2019)
        
          - fix <path> type routing
          - change URL build alias from was.urlspec ()
          - change URL build alias from was.ab () to was.urlfor ()
          - add alias was.urlpatch () for was.partial () for clarity
          - add session.impending () and session.use_time ()
          - change default options for Jinja2
          - change session key name
          - fix session expireation
          - add extend param to session.mount ()
          - add was.render_or_API ()
          - add was.request.acceptables and was.request.acceptable (media)
          - fix @app.fix testpass_required when reloading
          - change session.mount spec
          - fix multiple mount bug related `enable_namespace`
          - fix websocket bug related `enable_namespace`
          - `app.auto_mount` was deprecated
          - default value of  `app.enable_namespace` has been
            from False to True. ACTION REQUIRED, lower version
            incompatible
        
        - 0.6 (Oct, 2019)
        
          - fix query string exception handling
          - readd Chameleon template engine chapter to README
          - test on PyPy
        
        - 0.5 (Sep, 2019)
        
          - add app example
          - update requirements
        
        - 0.4 (Aug, 2019)
        
          - now, modules within \_\_mount\_\_ are reloadable
          - deprecated @app.test_params, use @app.require
          - deprecated was.Future and was.Futures, it doesn't need.
        
        - 0.3 (Mar 13, 2019)
        
          - remove proxing django route
          - remove login service with django
          - remove django model signal redirecting
          - add @app.require
          - change mount handler: def mount (app) =>
            def __mount__ (app) but lower version compatible
          - make available @app.route ("")
          - add was.proxypass (alias, path, timeout = 3)
          - add special pre-defined URL parameter value: me, notme, new
          - add parameter validation, now response code 400,
            if validatiion if failed
          - fix implicit routing
          - add conditional permission control
        
        - 0.2 (Feb 18, 2019)
        
          - fix implicit routing for root
          - remove jinja2 from requirements
          - add app.websocket_send ()
          - fix Futures respinse bugs
          - add was.API (), was.Fault (), was.File and
            was.Futures ()
        
        - 0.1 (Jan 17, 2019)
        
          - was.promise () has been deprecated, use was.Futures ()
          - add interval based maintain jobs executor
          - change name from app.storage to app.store
          - add default_bearer_handler
          - fix routing bugs related fancy URL
          - add was.request.URL, DEFAULT, FORM (former was.request.form ()),
            JSON (former was.request.json ()), DATA (former was.request.data),
            ARGS (former was.request.args)
          - add @app.test_param (required = None, ints = None, floats = None)
          - project has been seperated from skitai and rename from
            saddle to atila, because saddle project is already exist on PYPI
        
Platform: posix
Platform: nt
Classifier: License :: OSI Approved :: MIT License
Classifier: Development Status :: 4 - Beta
Classifier: Topic :: Internet :: WWW/HTTP :: WSGI
Classifier: Environment :: Console
Classifier: Topic :: Internet
Classifier: Topic :: Software Development :: Libraries :: Python Modules
Classifier: Intended Audience :: Developers
Classifier: Programming Language :: Python :: 3.5
Classifier: Programming Language :: Python :: 3.6
Classifier: Programming Language :: Python :: 3.7
Classifier: Programming Language :: Python :: Implementation :: CPython
Classifier: Programming Language :: Python :: Implementation :: PyPy
