"""Simplistic HTTP proxy support.
This comes in two main variants - the Proxy and the ReverseProxy.
When a Proxy is in use, a browser trying to connect to a server (say,
www.yahoo.com) will be intercepted by the Proxy, and the proxy will covertly
connect to the server, and return the result.
When a ReverseProxy is in use, the client connects directly to the ReverseProxy
(say, www.yahoo.com) which farms off the request to one of a pool of servers,
and returns the result.
Normally, a Proxy is used on the client end of an Internet connection, while a
ReverseProxy is used on the server end.
"""
from twisted.protocols import http
from twisted.internet import reactor, protocol
from twisted.web import resource, server
import urlparse
class ProxyClient(http.HTTPClient):
"""Used by ProxyClientFactory to implement a simple web proxy."""
def __init__(self, command, rest, version, headers, data, father):
self.father = father
self.command = command
self.rest = rest
if headers.has_key("proxy-connection"):
del headers["proxy-connection"]
headers["connection"] = "close"
self.headers = headers
self.data = data
def connectionMade(self):
self.sendCommand(self.command, self.rest)
for header, value in self.headers.items():
self.sendHeader(header, value)
self.endHeaders()
self.transport.write(self.data)
def handleStatus(self, version, code, message):
self.father.transport.write("%s %s %s\r\n" % (version, code, message))
def handleHeader(self, key, value):
self.father.transport.write("%s: %s\r\n" % (key, value))
def handleEndHeaders(self):
self.father.transport.write("\r\n")
def handleResponsePart(self, buffer):
self.father.transport.write(buffer)
def handleResponseEnd(self):
self.transport.loseConnection()
self.father.channel.transport.loseConnection()
class ProxyClientFactory(protocol.ClientFactory):
"""Used by ProxyRequest to implement a simple web proxy."""
def __init__(self, command, rest, version, headers, data, father):
self.father = father
self.command = command
self.rest = rest
self.headers = headers
self.data = data
self.version = version
def buildProtocol(self, addr):
return ProxyClient(self.command, self.rest, self.version,
self.headers, self.data, self.father)
def clientConnectionFailed(self, connector, reason):
self.father.transport.write("HTTP/1.0 501 Gateway error\r\n")
self.father.transport.write("Content-Type: text/html\r\n")
self.father.transport.write("\r\n")
self.father.transport.write('''<H1>Could not connect</H1>''')
class ProxyRequest(http.Request):
"""Used by Proxy to implement a simple web proxy."""
protocols = {'http': ProxyClientFactory}
ports = {'http': 80}
def process(self):
parsed = urlparse.urlparse(self.uri)
protocol = parsed[0]
host = parsed[1]
port = self.ports[protocol]
if ':' in host:
host, port = host.split(':')
port = int(port)
rest = urlparse.urlunparse(('','')+parsed[2:])
if not rest:
rest = rest+'/'
class_ = self.protocols[protocol]
headers = self.getAllHeaders().copy()
if not headers.has_key('host'):
headers['host'] = host
self.content.seek(0, 0)
s = self.content.read()
clientFactory = class_(self.method, rest, self.clientproto, headers,
s, self)
reactor.connectTCP(host, port, clientFactory)
class Proxy(http.HTTPChannel):
"""This class implements a simple web proxy.
Since it inherits from twisted.protocols.http.HTTPChannel, to use it you
should do something like this::
from twisted.protocols import http
f = http.HTTPFactory()
f.protocol = Proxy
Make the HTTPFactory a listener on a port as per usual, and you have
a fully-functioning web proxy!
"""
requestFactory = ProxyRequest
class ReverseProxyRequest(http.Request):
"""Used by ReverseProxy to implement a simple reverse proxy."""
def process(self):
self.received_headers['host'] = self.factory.host
clientFactory = ProxyClientFactory(self.method, self.uri,
self.clientproto,
self.getAllHeaders(),
self.content.read(), self)
reactor.connectTCP(self.factory.host, self.factory.port,
clientFactory)
class ReverseProxy(http.HTTPChannel):
"""Implements a simple reverse proxy.
For details of usage, see the file examples/proxy.py"""
requestFactory = ReverseProxyRequest
class ReverseProxyResource(resource.Resource):
"""Resource that renders the results gotten from another server
Put this resource in the tree to cause everything below it to be relayed
to a different server.
"""
def __init__(self, host, port, path):
resource.Resource.__init__(self)
self.host = host
self.port = port
self.path = path
def getChild(self, path, request):
return ReverseProxyResource(self.host, self.port, self.path+'/'+path)
def render(self, request):
request.received_headers['host'] = self.host
request.content.seek(0, 0)
qs = urlparse.urlparse(request.uri)[4]
if qs:
rest = self.path + '?' + qs
else:
rest = self.path
clientFactory = ProxyClientFactory(request.method, rest,
request.clientproto,
request.getAllHeaders(),
request.content.read(),
request)
reactor.connectTCP(self.host, self.port, clientFactory)
return server.NOT_DONE_YET