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I run the python websocket server of the
websokets
module on the
localhost:5005
. The code from
documentation page
:
#!/usr/bin/env python
import asyncio
import websockets
import logging
logger = logging.getLogger('websockets')
logger.setLevel(logging.DEBUG)
logger.addHandler(logging.StreamHandler())
async def echo(websocket):
async for message in websocket:
print(message)
await websocket.send(message)
async def main():
async with websockets.serve(echo, "localhost", 5005):
await asyncio.Future() # run forever
asyncio.run(main())
Clients can access it by connecting to the URL ws://localhost:5005. A sample client code is given in the websockets module documentation page.
The goal is to enable clients to access the server via IIS (Windows native webserver) acting as a reverse proxy, i.e., via the URL ws://localhost/app.
IIS-10 settings:
Application Request Routing Cache --> Server Proxy Setting --> Enable proxy
Sites --> Default Web Site: I added an application named app
URL Rewrite: I added the following rule:
<?xml version="1.0" encoding="UTF-8"?>
<configuration>
<system.webServer>
<rewrite>
<rules>
<rule name="ReverseProxy" stopProcessing="true">
<match url="(.*)" />
<action type="Rewrite" url="http://localhost:5005" logRewrittenUrl="true" />
</rule>
</rules>
</rewrite>
</system.webServer>
</configuration>
As soon as a client attempts to connect, it gets disconnected and the server throws this exception:
= connection is CONNECTING
< GET / HTTP/1.1
< Cache-Control: no-cache
< Connection: Upgrade
< Pragma: no-cache
< Upgrade: websocket
< Accept-Encoding: gzip, deflate, br, peerdist
< Accept-Language: en-US,en;q=0.9
< Host: localhost:5005
< Max-Forwards: 10
< User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/103.0.0.0 Safari/537.36
< Origin: null
< Sec-WebSocket-Version: 13
< Sec-WebSocket-Key: /C9ah/z+wAo4mnoACSz2IA==
< Sec-WebSocket-Extensions: permessage-deflate; client_max_window_bits
< X-Original-URL: /app
< X-Forwarded-For: [::1]:52798
< X-ARR-LOG-ID: 8c59749a-4e5d-43cf-8a5a-c4421cc4ecc8
< X-P2P-PeerDist: Version=1.1
< X-P2P-PeerDistEx: MinContentInformation=1.0, MaxContentInformation=2.0
> HTTP/1.1 101 Switching Protocols
> Upgrade: websocket
> Connection: Upgrade
> Sec-WebSocket-Accept: W9Sttf7fHX3aB9zd4b/PVGt0Ldg=
> Sec-WebSocket-Extensions: permessage-deflate; server_max_window_bits=12; client_max_window_bits=12
> Date: Fri, 15 Jul 2022 19:14:32 GMT
> Server: Python/3.7 websockets/10.3
connection open
= connection is OPEN
! failing connection with code 1006
= connection is CLOSED
x half-closing TCP connection
connection handler failed
Traceback (most recent call last):
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\protocol.py", line 945, in transfer_data
message = await self.read_message()
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\protocol.py", line 1015, in read_message
frame = await self.read_data_frame(max_size=self.max_size)
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\protocol.py", line 1090, in read_data_frame
frame = await self.read_frame(max_size)
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\protocol.py", line 1149, in read_frame
extensions=self.extensions,
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\framing.py", line 70, in read
data = await reader(2)
File "C:\Program Files\Python37\lib\asyncio\streams.py", line 677, in readexactly
raise IncompleteReadError(incomplete, n)
asyncio.streams.IncompleteReadError: 0 bytes read on a total of 2 expected bytes
The above exception was the direct cause of the following exception:
Traceback (most recent call last):
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\server.py", line 232, in handler
await self.ws_handler(self)
File "D:/Robotic Framework/RoboticApps/UI_Framework/server.py", line 12, in echo
async for message in websocket:
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\protocol.py", line 482, in __aiter__
yield await self.recv()
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\protocol.py", line 553, in recv
await self.ensure_open()
File "C:\Users\amin.ramezanifar\AppData\Roaming\Python\Python37\site-packages\websockets\legacy\protocol.py", line 921, in ensure_open
raise self.connection_closed_exc()
websockets.exceptions.ConnectionClosedError: no close frame received or sent
connection closed
To make sure if IIS settings are correct, I used another websocket library named "simple-websocket-server" from here and it worked fine. Also I tried a simple Node.js server from here and it was successful.
What could be wrong?
–
–
Amin (question author) and I figured out that you have to disable compression in websockets because IIS doesn't support it.
It worked with other libraries because they don't implement compression or don't enable it by default, unlike websockets.
For details, see the discussion on GitHub: https://github.com/aaugustin/websockets/issues/1192
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