Class Application

python/python3/tornado/web.py:1961–2276

r"""A collection of request handlers that make up a web application. Instances of this class are callable and can be passed directly to HTTPServer to serve the application:: application = web.Application([ (r"/", MainPageHandler), ]) http_server = httpse

class Application(ReversibleRouter):
    r"""A collection of request handlers that make up a web application.

    Instances of this class are callable and can be passed directly to
    HTTPServer to serve the application::

        application = web.Application([
            (r"/", MainPageHandler),
        ])
        http_server = httpserver.HTTPServer(application)
        http_server.listen(8080)

    The constructor for this class takes in a list of `~.routing.Rule`
    objects or tuples of values corresponding to the arguments of
    `~.routing.Rule` constructor: ``(matcher, target, [target_kwargs], [name])``,
    the values in square brackets being optional. The default matcher is
    `~.routing.PathMatches`, so ``(regexp, target)`` tuples can also be used
    instead of ``(PathMatches(regexp), target)``.

    A common routing target is a `RequestHandler` subclass, but you can also
    use lists of rules as a target, which create a nested routing configuration::

        application = web.Application([
            (HostMatches("example.com"), [
                (r"/", MainPageHandler),
                (r"/feed", FeedHandler),
            ]),
        ])

    In addition to this you can use nested `~.routing.Router` instances,
    `~.httputil.HTTPMessageDelegate` subclasses and callables as routing targets
    (see `~.routing` module docs for more information).

    When we receive requests, we iterate over the list in order and
    instantiate an instance of the first request class whose regexp
    matches the request path. The request class can be specified as
    either a class object or a (fully-qualified) name.

    A dictionary may be passed as the third element (``target_kwargs``)
    of the tuple, which will be used as keyword arguments to the handler's
    constructor and `~RequestHandler.initialize` method. This pattern
    is used for the `StaticFileHandler` in this example (note that a
    `StaticFileHandler` can be installed automatically with the
    static_path setting described below)::

        application = web.Application([
            (r"/static/(.*)", web.StaticFileHandler, {"path": "/var/www"}),
        ])

    We support virtual hosts with the `add_handlers` method, which takes in
    a host regular expression as the first argument::

        application.add_handlers(r"www\.myhost\.com", [
            (r"/article/([0-9]+)", ArticleHandler),
        ])

    If there's no match for the current request's host, then ``default_host``
    parameter value is matched against host regular expressions.