Asyncio Autobahn behind reverse proxy rejecting connection - python-3.x

Question

I'm using Autobahn with Asyncio to build a lightweight socket server separate from my flask app. I have it all working but in order to route the traffic accordingly I put the two servers behind HAProxy. I am successfully getting requests to the server, but then the connection closes and server reports:
WebSocket connection closed: connection was closed uncleanly (port 9001 in HTTP Host header 'localhost:9001' does not match server listening port 4000)
So, the header does not match what the server is expecting. Is there any way to change this?
I am using Autobahn-python version 0.10.9 with Python 3.4. Here is my server code:
from autobahn.asyncio.websocket import WebSocketServerProtocol, \
WebSocketServerFactory
import asyncio
import json
class SimpleServer(WebSocketServerProtocol):
def onConnect(self, request):
print("Client connecting: {0}".format(request.peer))
def onOpen(self):
print("WebSocket connection open.")
#asyncio.coroutine
def onMessage(self, payload, isBinary):
if not isBinary:
self.sendMessage(payload, isBinary)
else:
self.sendMessage(payload, isBinary)
def onClose(self, wasClean, code, reason):
print("WebSocket connection closed: {0}".format(reason))
if __name__ == '__main__':
factory = WebSocketServerFactory(u"ws://127.0.0.1:4000", debug=False)
factory.protocol = SimpleServer
loop = asyncio.get_event_loop()
coro = loop.create_server(factory, '127.0.0.1', 4000)
server = loop.run_until_complete(coro)
try:
loop.run_forever()
except KeyboardInterrupt:
pass
finally:
server.close()
loop.close()
HAProxy is version 1.4.18 and the config is:
global
log 127.0.0.1› local0
log 127.0.0.1› local1 notice
maxconn 4096
user root
group sudo
debug
#quiet
defaults
log global
mode http
option httplog
option dontlognull
retries 3
option redispatch
maxconn 2000
contimeout 5000
clitimeout 50000
srvtimeout 50000
frontend public
bind *:9001
acl is_websocket hdr(Upgrade) -i WebSocket
use_backend ws if is_websocket
default_backend www
backend www
timeout server 30s
server www1 127.0.0.1:3000
backend ws
timeout server 600s
server ws1 127.0.0.1:4000
I am running Ubuntu 12.04. Thanks for the help

Answer 1

Ok for anyone stuck on this, it was fixed by changing
factory = WebSocketServerFactory(u"ws://127.0.0.1:4000", debug=False)
to:
factory = WebSocketServerFactory()
Apparently, specifying the url in the Factory will cause Autobahn to run checks on the headers.