[Twisted-Python] ProxyClient error using ReverseProxy

[David McCurley]

I'm working on full reverse proxy functionality and have run into an
error (twisted 1.0.6) during some basic testing.

SYNOPSIS:

- Made a root ReverseProxyResource that goes to google from
http://localhost:8080/ in my web.tap

- Using Mozilla 1.4, hit the local url, all is okay

- Now click the refresh button and an exception is thrown in the console
window running the tap.

- Reload again and no error, reload again and exception, repeatable
every other time.

I'm not clear on the full call details but the refresh that causes the
exception has a request already queued, so when the
ProxyClient.handleRequest calls the self.father.transport.loseConnection
method, the exception triggers because the transport is a
StringTransport in the queued request and it doesn't have a
"loseConnection" method.

I've been trying to trace this to submit a patch, but its not clear to
me what the queuing is for or why this is happening, or when to call
loseConnection.

DETAILS:

Made an .rpy file and a web tap that made it the root resource:

t1.rpy
===========================
import twisted.web.proxy

resource = twisted.web.proxy.ReverseProxyResource('www.google.com', 80,
'')
===========================

In mozilla 1.4 get http://localhost:8080/

Console output:
====================
2003/07/25 19:03 EDT [HTTPChannel,0,127.0.0.1] Starting factory
<twisted.web.proxy.ProxyClientFactory instance at 0x840eccc>
2003/07/25 19:03 EDT [ProxyClient,client] Stopping factory
<twisted.web.proxy.ProxyClientFactory instance at 0x840eccc>
2003/07/25 19:03 EDT [HTTPChannel,1,127.0.0.1] Starting factory
<twisted.web.proxy.ProxyClientFactory instance at 0x8416fb4>
====================

Now click reload after a few seconds (Mozilla icon stays spinning this
time like it has an open connection its waiting on):

Console output:
====================
2003/07/25 19:04 EDT [HTTPChannel,1,127.0.0.1] Starting factory
<twisted.web.proxy.ProxyClientFactory instance at 0x8411b3c>
2003/07/25 19:04 EDT [ProxyClient,client] Traceback (most recent call
last):
          File
"/usr/lib/python2.2/site-packages/twisted/internet/default.py", line
472, in doSelect
            _logrun(selectable, _drdw, selectable, method, dict)
          File "/usr/lib/python2.2/site-packages/twisted/python/log.py",
line 65, in callWithLogger
            callWithContext({"system": lp}, func, *args, **kw)
          File "/usr/lib/python2.2/site-packages/twisted/python/log.py",
line 52, in callWithContext
            return context.call({ILogContext: newCtx}, func, *args,
**kw)
          File
"/usr/lib/python2.2/site-packages/twisted/python/context.py", line 32,
in callWithContext
            return func(*args,**kw)
        --- <exception caught here> ---
          File
"/usr/lib/python2.2/site-packages/twisted/internet/default.py", line
481, in _doReadOrWrite
            why = getattr(selectable, method)()
          File
"/usr/lib/python2.2/site-packages/twisted/internet/tcp.py", line
216, in doRead
            return self.protocol.dataReceived(data)
          File
"/usr/lib/python2.2/site-packages/twisted/protocols/basic.py", line 184,
in dataReceived
            return self.rawDataReceived(data)
          File
"/usr/lib/python2.2/site-packages/twisted/protocols/http.py", line 354,
in rawDataReceived
            self.handleResponseEnd()
          File
"/usr/lib/python2.2/site-packages/twisted/protocols/http.py", line 336,
in handleResponseEnd
            self.handleResponse(b)
          File "proxy.py", line 72, in handleResponse
             
          File
"/usr/lib/python2.2/site-packages/twisted/protocols/http.py", line 285,
in __getattr__
            return getattr(self.__dict__['s'], attr)
        exceptions.AttributeError: loseConnection
 
2003/07/25 19:04 EDT [ProxyClient,client] Stopping factory
<twisted.web.proxy.ProxyClientFactory instance at 0x8411b3c>

====================

Reload again and this time the following output happens at the console
and the Mozilla icon stops spinning like all connections are closed.

Console output:
====================
2003/07/25 19:04 EDT [HTTPChannel,2,127.0.0.1] Starting factory
<twisted.web.proxy.ProxyClientFactory instance at 0x84266ac>
2003/07/25 19:04 EDT [ProxyClient,client] Stopping factory
<twisted.web.proxy.ProxyClientFactory instance at 0x84266ac>
2003/07/25 19:04 EDT [HTTPChannel,3,127.0.0.1] Starting factory
<twisted.web.proxy.ProxyClientFactory instance at 0x84454a4>
====================

Reload again and it starts spinning and gives same type of exception
trace as above.

Any pointers on where to look or how to fix this?

Thanks,

David