Set websocket=True for Rule, fixes #81

[tomviner]

This fixes the WebsocketMismatch which appears with Werkzeug 2.0.0.

The cause is a websocket request hits a rule which Werkzeug doesn't think is a websocket endpoint.

[tomviner]

Unfortunately, Werkzeug pre 2.0.0 doesn't always label websocket requests correctly, so with this PR, you can end up with the opposite mismatch.

Here's the change to Werkzeug where more websocket requests get labelled correctly: https://github.com/pallets/werkzeug/pull/2053/files#diff-9b2e55f893697ae8ac344aebf17bebee83546fc2bf4d8e1b138cf7c63e92080fR1637-R1641

[lnstadrum]

Hi @tomviner,

I ended up with a similar change to make things work on my side, but in addition to your commit I also had to add the following change:

@@ -27,7 +27,7 @@ class SocketMiddleware(object):
     def __call__(self, environ, start_response):
         adapter = self.ws.url_map.bind_to_environ(environ)
         try:
-            handler, values = adapter.match()
+            handler, values = adapter.match(websocket=True)
             environment = environ['wsgi.websocket']
             cookie = None
             if 'HTTP_COOKIE' in environ:

In my tests this makes WebsocketMismatch disappear for a web page socket and a socket opened in Android with Kotlin Ktor API. Not sure if this is universally helpful though... My setup was as follows:

• Python 3.8.5
• Flask 2.0.0
• Werkzeug 2.0.1
• gunicorn 20.1.0

[atzannes]

@tomviner thanks for this fix. It looks like it fixes most of my problems with the Flask upgrade.

Unfortunately, Werkzeug pre 2.0.0 doesn't always label websocket requests correctly, so with this PR, you can end up with the opposite mismatch.

Here's the change to Werkzeug where more websocket requests get labelled correctly: https://github.com/pallets/werkzeug/pull/2053/files#diff-9b2e55f893697ae8ac344aebf17bebee83546fc2bf4d8e1b138cf7c63e92080fR1637-R1641

Maybe also add the constraint Flask>=2.0 in setup.py then.

[Rosuav]

If there's an issue with misrecognizing sockets, maybe the solution would be to use the options kwargs instead?

self.url_map.add(Rule(rule, endpoint=f, **options))

And then you'd use it thus:

@sockets.route("/countdown_ctrl", websocket=True)
def control_socket(ws):

Older versions of flask_sockets would ignore that, so an app that sets this flag would be compatible with both.

[hansehe]

If there's an issue with misrecognizing sockets, maybe the solution would be to use the options kwargs instead?

self.url_map.add(Rule(rule, endpoint=f, **options))

And then you'd use it thus:

@sockets.route("/countdown_ctrl", websocket=True)
def control_socket(ws):

Older versions of flask_sockets would ignore that, so an app that sets this flag would be compatible with both.

This solution would solve it, so someone really needs to fix that! It's an easy fix, and would help a lot.
For anyone looking for a temporary solution, then you could do this:
'''
sockets.url_map.add(Rule('/mixed_ws_path', endpoint=my_websocket_function, websocket=True))
'''