# -*- coding: utf-8 -*- # Copyright 2019 The Matrix.org Foundation C.I.C. # # Licensed under the Apache License, Version 2.0 (the "License"); # you may not use this file except in compliance with the License. # You may obtain a copy of the License at # # http://www.apache.org/licenses/LICENSE-2.0 # # Unless required by applicable law or agreed to in writing, software # distributed under the License is distributed on an "AS IS" BASIS, # WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. # See the License for the specific language governing permissions and # limitations under the License. import logging import re from zope.interface import implementer from twisted.internet import defer from twisted.internet.endpoints import HostnameEndpoint, wrapClientTLS from twisted.python.failure import Failure from twisted.web.client import URI, BrowserLikePolicyForHTTPS, _AgentBase from twisted.web.error import SchemeNotSupported from twisted.web.iweb import IAgent from synapse.http.connectproxyclient import HTTPConnectProxyEndpoint logger = logging.getLogger(__name__) _VALID_URI = re.compile(br"\A[\x21-\x7e]+\Z") @implementer(IAgent) class ProxyAgent(_AgentBase): """An Agent implementation which will use an HTTP proxy if one was requested Args: reactor: twisted reactor to place outgoing connections. contextFactory (IPolicyForHTTPS): A factory for TLS contexts, to control the verification parameters of OpenSSL. The default is to use a `BrowserLikePolicyForHTTPS`, so unless you have special requirements you can leave this as-is. connectTimeout (float): The amount of time that this Agent will wait for the peer to accept a connection. bindAddress (bytes): The local address for client sockets to bind to. pool (HTTPConnectionPool|None): connection pool to be used. If None, a non-persistent pool instance will be created. """ def __init__( self, reactor, contextFactory=BrowserLikePolicyForHTTPS(), connectTimeout=None, bindAddress=None, pool=None, http_proxy=None, https_proxy=None, ): _AgentBase.__init__(self, reactor, pool) self._endpoint_kwargs = {} if connectTimeout is not None: self._endpoint_kwargs["timeout"] = connectTimeout if bindAddress is not None: self._endpoint_kwargs["bindAddress"] = bindAddress self.http_proxy_endpoint = _http_proxy_endpoint( http_proxy, reactor, **self._endpoint_kwargs ) self.https_proxy_endpoint = _http_proxy_endpoint( https_proxy, reactor, **self._endpoint_kwargs ) self._policy_for_https = contextFactory self._reactor = reactor def request(self, method, uri, headers=None, bodyProducer=None): """ Issue a request to the server indicated by the given uri. Supports `http` and `https` schemes. An existing connection from the connection pool may be used or a new one may be created. See also: twisted.web.iweb.IAgent.request Args: method (bytes): The request method to use, such as `GET`, `POST`, etc uri (bytes): The location of the resource to request. headers (Headers|None): Extra headers to send with the request bodyProducer (IBodyProducer|None): An object which can generate bytes to make up the body of this request (for example, the properly encoded contents of a file for a file upload). Or, None if the request is to have no body. Returns: Deferred[IResponse]: completes when the header of the response has been received (regardless of the response status code). """ uri = uri.strip() if not _VALID_URI.match(uri): raise ValueError("Invalid URI {!r}".format(uri)) parsed_uri = URI.fromBytes(uri) pool_key = (parsed_uri.scheme, parsed_uri.host, parsed_uri.port) request_path = parsed_uri.originForm if parsed_uri.scheme == b"http" and self.http_proxy_endpoint: # Cache *all* connections under the same key, since we are only # connecting to a single destination, the proxy: pool_key = ("http-proxy", self.http_proxy_endpoint) endpoint = self.http_proxy_endpoint request_path = uri elif parsed_uri.scheme == b"https" and self.https_proxy_endpoint: endpoint = HTTPConnectProxyEndpoint( self._reactor, self.https_proxy_endpoint, parsed_uri.host, parsed_uri.port, ) else: # not using a proxy endpoint = HostnameEndpoint( self._reactor, parsed_uri.host, parsed_uri.port, **self._endpoint_kwargs ) logger.debug("Requesting %s via %s", uri, endpoint) if parsed_uri.scheme == b"https": tls_connection_creator = self._policy_for_https.creatorForNetloc( parsed_uri.host, parsed_uri.port ) endpoint = wrapClientTLS(tls_connection_creator, endpoint) elif parsed_uri.scheme == b"http": pass else: return defer.fail( Failure( SchemeNotSupported("Unsupported scheme: %r" % (parsed_uri.scheme,)) ) ) return self._requestWithEndpoint( pool_key, endpoint, method, parsed_uri, headers, bodyProducer, request_path ) def _http_proxy_endpoint(proxy, reactor, **kwargs): """Parses an http proxy setting and returns an endpoint for the proxy Args: proxy (bytes|None): the proxy setting reactor: reactor to be used to connect to the proxy kwargs: other args to be passed to HostnameEndpoint Returns: interfaces.IStreamClientEndpoint|None: endpoint to use to connect to the proxy, or None """ if proxy is None: return None # currently we only support hostname:port. Some apps also support # protocol://[:port], which allows a way of requiring a TLS connection to the # proxy. host, port = parse_host_port(proxy, default_port=1080) return HostnameEndpoint(reactor, host, port, **kwargs) def parse_host_port(hostport, default_port=None): # could have sworn we had one of these somewhere else... if b":" in hostport: host, port = hostport.rsplit(b":", 1) try: port = int(port) return host, port except ValueError: # the thing after the : wasn't a valid port; presumably this is an # IPv6 address. pass return hostport, default_port