flask.cli DispatchingApp Example Code

DispatchingApp is a class within the flask.cli module of the Flask project. DispatchingApp is a special application that dispatches to a Flask app if it is imported by name in a background thread.

AppGroup, FlaskGroup, ScriptInfo, pass_script_info, and with_appcontext are several other callables with code examples from the same flask.cli package.

Example 1 from indico

indico (project website, documentation and sandbox demo) is a Flask-based web app for event management. The code is open sourced under the MIT license.

indico / indico / cli / devserver.py

# devserver.py

from __future__ import print_function, unicode_literals

import os

from flask.cli import DispatchingApp
from werkzeug.debug import DebuggedApplication
from werkzeug.exceptions import NotFound
from werkzeug.middleware.dispatcher import DispatcherMiddleware
from werkzeug.middleware.proxy_fix import ProxyFix
from werkzeug.serving import WSGIRequestHandler, run_simple
from werkzeug.urls import url_parse


try:
    import pywatchman
except ImportError:
    pywatchman = None


def run_cmd(info, **kwargs):
    if kwargs['reloader_type'] == 'watchman':
        if pywatchman is None:
            print('watchman is not available - you need to `pip install pywatchman`')
            return
        run_watchman()
        return
    run_server(info, **kwargs)




## ... source file abbreviated to get to DispatchingApp examples ...



    import logging
    werkzeug_logger = logging.getLogger('werkzeug')
    werkzeug_logger.propagate = False
    werkzeug_logger.setLevel(logging.INFO)
    werkzeug_logger.addHandler(logging.StreamHandler())

    app = _make_wsgi_app(info, url, evalex_whitelist, proxy)
    run_simple(host, port, app,
               reloader_type=reloader_type, use_reloader=(reloader_type != 'none'),
               use_debugger=False, use_evalex=False, threaded=True, ssl_context=ssl_ctx,
               extra_files=extra_files, request_handler=QuietWSGIRequestHandler if quiet else None)


def _reset_state():
    from indico.core.celery import celery
    celery.flask_app = None


def _make_wsgi_app(info, url, evalex_whitelist, proxy):
    def _load_app():
        _reset_state()
        return info.load_app()

    url_data = url_parse(url)
    app = DispatchingApp(_load_app)
    app = DebuggedIndico(app, evalex_whitelist)
    app = _make_indico_dispatcher(app, url_data.path)
    if proxy:
        app = ProxyFix(app, x_for=1, x_proto=1, x_host=1)
    QuietWSGIRequestHandler.INDICO_URL_PREFIX = url_data.path.rstrip('/')
    return app


def _make_indico_dispatcher(wsgi_app, path):
    path = path.rstrip('/')
    if not path:
        return wsgi_app
    else:
        return DispatcherMiddleware(NotFound(), {
            path: wsgi_app
        })


class DebuggedIndico(DebuggedApplication):
    def __init__(self, *args, **kwargs):
        self._evalex_whitelist = None
        self._request_ip = None
        super(DebuggedIndico, self).__init__(*args, **kwargs)



## ... source file continues with no further DispatchingApp examples...

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