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Diffstat (limited to 'synapse/http/proxyagent.py')
| -rw-r--r-- | synapse/http/proxyagent.py | 195 |
1 files changed, 195 insertions, 0 deletions
diff --git a/synapse/http/proxyagent.py b/synapse/http/proxyagent.py new file mode 100644 index 0000000000..332da02a8d --- /dev/null +++ b/synapse/http/proxyagent.py @@ -0,0 +1,195 @@ +# -*- 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://<host>[: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 |