https_forwarder.py revision 5d1f7b1de12d16ceb2c938c56701a3e8bfa558f7 
1# Copyright 2014 The Chromium Authors. All rights reserved.
2# Use of this source code is governed by a BSD-style license that can be
3# found in the LICENSE file.
4
5"""An https server that forwards requests to another server. This allows a
6server that supports http only to be accessed over https.
7"""
8
9import BaseHTTPServer
10import os
11import SocketServer
12import sys
13import urllib2
14import urlparse
15import testserver_base
16import tlslite.api
17
18
19class RedirectSuppressor(urllib2.HTTPErrorProcessor):
20  """Prevents urllib2 from following http redirects.
21
22  If this class is placed in an urllib2.OpenerDirector's handler chain before
23  the default urllib2.HTTPRedirectHandler, it will terminate the processing of
24  responses containing redirect codes (301, 302, 303, 307) before they reach the
25  default redirect handler.
26  """
27
28  def http_response(self, req, response):
29    return response
30
31  def https_response(self, req, response):
32    return response
33
34
35class RequestForwarder(BaseHTTPServer.BaseHTTPRequestHandler):
36  """Handles requests received by forwarding them to the another server."""
37
38  def do_GET(self):
39    """Forwards GET requests."""
40    self._forward(None)
41
42  def do_POST(self):
43    """Forwards POST requests."""
44    self._forward(self.rfile.read(int(self.headers['Content-Length'])))
45
46  def _forward(self, body):
47    """Forwards a GET or POST request to another server.
48
49    Args:
50      body: The request body. This should be |None| for GET requests.
51    """
52    request_url = urlparse.urlparse(self.path)
53    url = urlparse.urlunparse((self.server.forward_scheme,
54                               self.server.forward_netloc,
55                               self.server.forward_path + request_url[2],
56                               request_url[3],
57                               request_url[4],
58                               request_url[5]))
59
60    headers = dict((key, value) for key, value in dict(self.headers).iteritems()
61                   if key.lower() != 'host')
62    opener = urllib2.build_opener(RedirectSuppressor)
63    forward = opener.open(urllib2.Request(url, body, headers))
64
65    self.send_response(forward.getcode())
66    for key, value in dict(forward.info()).iteritems():
67      self.send_header(key, value)
68    self.end_headers()
69    self.wfile.write(forward.read())
70
71
72class MultiThreadedHTTPSServer(SocketServer.ThreadingMixIn,
73                               tlslite.api.TLSSocketServerMixIn,
74                               testserver_base.ClientRestrictingServerMixIn,
75                               testserver_base.BrokenPipeHandlerMixIn,
76                               testserver_base.StoppableHTTPServer):
77  """A multi-threaded version of testserver.HTTPSServer."""
78
79  def __init__(self, server_address, request_hander_class, pem_cert_and_key):
80    """Initializes the server.
81
82    Args:
83      server_address: Server host and port.
84      request_hander_class: The class that will handle requests to the server.
85      pem_cert_and_key: Path to file containing the https cert and private key.
86    """
87    self.cert_chain = tlslite.api.X509CertChain().parseChain(pem_cert_and_key)
88    # Force using only python implementation - otherwise behavior is different
89    # depending on whether m2crypto Python module is present (error is thrown
90    # when it is). m2crypto uses a C (based on OpenSSL) implementation under
91    # the hood.
92    self.private_key = tlslite.api.parsePEMKey(pem_cert_and_key,
93                                               private=True,
94                                               implementations=['python'])
95
96    testserver_base.StoppableHTTPServer.__init__(self,
97                                                 server_address,
98                                                 request_hander_class)
99
100  def handshake(self, tlsConnection):
101    """Performs the SSL handshake for an https connection.
102
103    Args:
104      tlsConnection: The https connection.
105    Returns:
106      Whether the SSL handshake succeeded.
107    """
108    try:
109      self.tlsConnection = tlsConnection
110      tlsConnection.handshakeServer(certChain=self.cert_chain,
111                                    privateKey=self.private_key)
112      tlsConnection.ignoreAbruptClose = True
113      return True
114    except:
115      return False
116
117
118class ServerRunner(testserver_base.TestServerRunner):
119  """Runner that starts an https server which forwards requests to another
120  server.
121  """
122
123  def create_server(self, server_data):
124    """Performs the SSL handshake for an https connection.
125
126    Args:
127      server_data: Dictionary that holds information about the server.
128    Returns:
129      The started server.
130    """
131    port = self.options.port
132    host = self.options.host
133
134    if not os.path.isfile(self.options.cert_and_key_file):
135      raise testserver_base.OptionError(
136          'Specified server cert file not found: ' +
137          self.options.cert_and_key_file)
138    pem_cert_and_key = open(self.options.cert_and_key_file).read()
139
140    server = MultiThreadedHTTPSServer((host, port),
141                                      RequestForwarder,
142                                      pem_cert_and_key)
143    print 'HTTPS server started on %s:%d...' % (host, server.server_port)
144
145    forward_target = urlparse.urlparse(self.options.forward_target)
146    server.forward_scheme = forward_target[0]
147    server.forward_netloc = forward_target[1]
148    server.forward_path = forward_target[2].rstrip('/')
149    server.forward_host = forward_target.hostname
150    if forward_target.port:
151      server.forward_host += ':' + str(forward_target.port)
152    server_data['port'] = server.server_port
153    return server
154
155  def add_options(self):
156    """Specifies the command-line options understood by the server."""
157    testserver_base.TestServerRunner.add_options(self)
158    self.option_parser.add_option('--https', action='store_true',
159                                  help='Ignored (provided for compatibility '
160                                  'only).')
161    self.option_parser.add_option('--cert-and-key-file', help='The path to the '
162                                  'file containing the certificate and private '
163                                  'key for the server in PEM format.')
164    self.option_parser.add_option('--forward-target', help='The URL prefix to '
165                                  'which requests will be forwarded.')
166
167
168if __name__ == '__main__':
169  sys.exit(ServerRunner().main())
170