BasicProxyHTTPServer.py

#!/bin/env python

''' 
proxy based on https://pypi.python.org/pypi/ProxyHTTPServer/
'''

import BaseHTTPServer, httplib, SocketServer, urllib, hashlib, urlparse
from base64 import b64decode

class DecodeError(Exception):
    pass

class BasicAuthHandler:
    """Handler for performing basic authentication."""

    def __init__(self):
        self._request_num = 0
        self._users = {}
        self._realm_name = "lugh.localdomain"

    def set_users(self, users):
        assert isinstance(users, dict)
        self._users = users

    def set_realm(self, realm):
        self._realm_name = realm

    def _create_auth_dict(self, auth_str):
    	# Remove the "Basic " part.
        first_space_index = auth_str.find(" ")
        auth_str = auth_str[first_space_index+1:]

        # auth_str now looks like nmVubfk652Vj1mV0
        try:
            username, password = b64decode(auth_str).split(':')
        except:
            raise DecodeError
        return { "username" : username, "password" : password }

    def _return_auth_challenge(self, request_handler):
        request_handler.send_response(407, "Proxy Authentication Required")
        request_handler.send_header("Content-Type", "text/html")
        request_handler.send_header('Proxy-Authenticate', 'Basic realm="%s"' % (self._realm_name))
        # XXX: Not sure if we're supposed to add this next header or
        # not.
        #request_handler.send_header('Connection', 'close')
        request_handler.end_headers()
        request_handler.wfile.write("Proxy Authentication Required.")
        return False

    def handle_request(self, request_handler):
        """Performs basic authentication on the given HTTP request
        handler.  Returns True if authentication was successful, False
        otherwise.

        If no users have been set, then basic auth is effectively
        disabled and this method will always return True.
        """

        if len(self._users) == 0:
            return True

        if 'Proxy-Authorization' not in request_handler.headers:
            return self._return_auth_challenge(request_handler)
        else:
            auth_dict = self._create_auth_dict(request_handler.headers['Proxy-Authorization'])
            if auth_dict["username"] in self._users:
                password = self._users[ auth_dict["username"] ]
            else:
                return self._return_auth_challenge(request_handler)
            auth_validated = False

            if password == auth_dict["password"]:
            	auth_validated = True

            if not auth_validated:
                return self._return_auth_challenge(request_handler)
            return True

class ProxyHTTPRequestHandler(BaseHTTPServer.BaseHTTPRequestHandler):

	basic_auth_handler = BasicAuthHandler()

	def doCommon(self):
		(scm, netloc, path, params, query, fragment) = urlparse.urlparse(self.path, 'http')
		self.short_path = path

		if self.basic_auth_handler.handle_request(self):
			req = Request(self)
			req.delHeaders("accept-encoding", "host", "proxy-connection")
			
			res = req.getResponse()
			res.delHeader("transfer-encoding")
			res.toClient()
		
	def do_GET(self):
		self.doCommon()

	def do_POST(self):
		self.doCommon()

class Request:
	def __init__(self, proxy):

		self.proxy = proxy
		self.host = proxy.headers.getheader("host")
		self.command = proxy.command
		self.path = proxy.path
		self.headers = proxy.headers.dict
		self.conn = httplib.HTTPConnection(self.host)
		
		if self.command == "POST":
			self.body = self.proxy.rfile.read(\
				int(self.proxy.headers.getheader("content-length")) )
		else:
			self.body = None
	
	def getHeader(self, k):
		if self.headers.has_key(k):
			return self.headers[k]
		else:
			return None
		
	def setHeader(self, k, v):
		self.headers[k] = v
	
	def setHeaders(self, dict):
		for i in dict.items():
			self.setHeader(i[0], i[1])
	
	def delHeader(self, k):
		if self.headers.has_key(k):
			del self.headers[k]
			
	def delHeaders(self, *list):
		for l in list:
			self.delHeader(l)
	
	def bodyDecode(self):
		m = MapList()
		for b in self.body.split("&"):
			for p in b.split("="):
				if p != "":
					m.add(urllib.unquote_plus(p[0]),
						urllib.unquote_plus(p[1]))
		return m
						
	def bodyEncode(self, mapList):
		body = ""
		for k in mapList.keys():
			for l in mapList.getList(k):
				body += "%s=%s&" % (urllib.quote_plus(k),
									urllib.quote_plus(l))
		if body == "":
			self.body = None
		else:
			self.body = body[:-1]
	
	def getResponse(self):
		if self.body:
			self.headers["content-length"] = str(len(self.body))
			self.conn.request("POST", self.path, self.body, self.headers)
		else:
			self.conn.request("GET", self.path, headers=self.headers)
			
		return Response(self.proxy, self.conn.getresponse())
			
class Response:
	def __init__(self, proxy, server):
		self.proxy = proxy
		self.server = server
		self.status = server.status
		self.body = server.read()
		
		self.headers = MapList()
		for l in server.getheaders():
			self.headers.add(l[0], l[1])

	def getHeader(self, k, index=-1):
		if self.headers.hasKey(k, index):
			return self.headers.get(k, index)
		else:
			return None
		
	def setHeader(self, k, v, index=-1):
		self.headers.set(k, v, index)
		
	def addHeader(self, k, v):
		self.headers.add(k, v)
	
	def addHeaders(self, dict):
		for i in dict.items():
			self.setHeader(i[0], i[1])
	
	def delHeader(self, k):
		if self.headers.hasKey(k):
			self.headers.delMap(k)
			
	def delHeaders(self, *list):
		for l in list:
			self.delHeader(l)
			
	def toClient(self):
		self.proxy.send_response(self.status)
		for k in self.headers.keys():
			for l in self.headers.getList(k):
				self.proxy.send_header(k, l)
		self.proxy.end_headers()
		self.proxy.wfile.write(self.body)

class MapList:
	def __init__(self):
		self.map = {}
	
	def __str__(self):
		return str(self.map)
		
	def add(self, k, v):
		if self.map.has_key(k):
			self.map[k].append(v)
		else:
			self.map[k] = [v]
			
	def set(self, k, v, index=-1):
		if self.map.has_key(k):
			self.map[k][index] = v
		else:
			self.map[k] = [v]
			
	def get(self,k, index=-1):
		return self.map[k][index]
		
	def getList(self,k):
		return self.map[k]
		
	def delMap(self, k):
		if self.map.has_key(k):
			del self.map[k]
			
	def delList(self, k, index=-1):
		if self.map.has_key(k):
			del self.map[k][index]
		
	def hasKey(self, k, index=-1):
		if self.map.has_key(k):
			l = self.map[k]
			if index < 0:
				index += 1
			if len(l) > abs(index):
				return True
		return False

	def keys(self):
		return self.map.keys()
		
	def mapSize(self):
		return len(self.map)
		
	def listSize(self, k):
		if self.map.has_key(k):
			return len(self.map[k])
		else:
			return 0
	
	def size(self):
		size = 0
		for i in self.map.items():
			size += len(i[1])
		return size
	

class ThreadingHTTPServer(SocketServer.ThreadingTCPServer, BaseHTTPServer.HTTPServer):
	pass
		
def test(HandlerClass = ProxyHTTPRequestHandler,
		ServerClass = ThreadingHTTPServer):

	ProxyHTTPRequestHandler.basic_auth_handler.set_users({'jenny':'supersecret'})
	ProxyHTTPRequestHandler.basic_auth_handler.set_realm('lugh.localdomain')
	BaseHTTPServer.test(HandlerClass, ServerClass)
	
if __name__ == '__main__':
	test()