Question

I have the following:

1. My webserver running on twisted
2. My comet server, aka orbited

Note that 1 and 2 are different processes.

Basically, I want 1 and 2 to share the same port. Request that are http://mysite.com/a/b/c should go to the webserver and anything starting with http://mysite.com/orbited/ should go to the orbited server, i.e. (http://mysite.com/orbited/a/b/c => do a request to http://mysite.com:12345/a/b/c and return that).

This is what I have right now:

# Reverse Proxy
class OrbitedResource(Resource):
    isLeaf = True

    def __init__(self, orbited_url='http://127.0.0.1:12345'):
        self.orbited = orbited_url
        Resource.__init__(self)

    def render_GET(self, request):

        def callback(html):
            request.write(html)
            request.finish()

        def errback(failure, *args):
            request.setResponseCode(http.INTERNAL_SERVER_ERROR)
            request.write(failure.getErrorMessage())
            request.finish()

        request.setHeader('Connection', 'close')

        # TODO find cleaner way to do this:
        # Currently request.uri is "/orbited/....", you must trim it
        target_uri = request.uri.replace('/orbited', '') 
        final_uri = self.orbited + target_uri
        print "final_uri is", final_uri

        deferred = getPage(final_uri)
        deferred.addCallbacks(callback, errback)
        return server.NOT_DONE_YET


class SimpleRoutingResource(Resource):
    isLeaf = False

    def __init__(self, wsgiApp):
        Resource.__init__(self)
        self.WSGIApp = wsgiApp
        self.orbitedResource = OrbitedResource()

    def getChild(self, name, request):
        if name == "orbited":
            request.prepath.pop()
            print "Simple request.path is", request.path
            return self.orbitedResource
        else: 
            request.prepath.pop()
            request.postpath.insert(0,name)
            return self.WSGIApp

# Attaching proxy + django 
log_dir = './.log'
if not os.path.exists(log_dir):
    os.makedirs(log_dir)
reactor.listenTCP(DJANGO_PORT, server.Site(SimpleRoutingResource(WSGIRoot), 
        logPath=os.path.join(log_dir, '.django.log')))

Currently this works . However, I see that there’s a class called ReverseProxyProtocol, and I have been doing tried it with the following modification:

class SimpleRoutingResource(Resource):
    isLeaf = False

    def __init__(self, wsgiApp):
        Resource.__init__(self)
        self.WSGIApp = wsgiApp

    def getChild(self, name, request):
        if name == "orbited":
            request.prepath.pop()
            print "Simple request.path is", request.path, name
            return ReverseProxyResource( 'http://localhost', 12345, name )
        else: 
            request.prepath.pop()
            request.postpath.insert(0,name)
            return self.WSGIApp

This is NOT Working. I have inserted a lot of prints into the twisted’s reverseProxyResource class, and I discovered the following:

1. Given http://mysite.com/orbited/a/b/c
2. OrbitedResource will keep calling ReverseProxyResource with getChild until c
3. by the time you get to c, the url is messed up and the client class calling the orbited server will be wrong
4. I tried setting isLeaf = True in the ReverseProxyResource, but to no avail.

Anybody can point me a more effecient way to write the getPage? Do I really need to use ReverseProxyResource if it’s such a black box in nature?

Answer 1

The cleanest way is to put something like nginx in front of both servers.