diff --git a/synapse/http/proxyagent.py b/synapse/http/proxyagent.py
index e32d3f43e0..ee65a6668b 100644
--- a/synapse/http/proxyagent.py
+++ b/synapse/http/proxyagent.py
@@ -12,9 +12,13 @@
# 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 base64
import logging
import re
+from typing import Optional, Tuple
+from urllib.request import getproxies_environment, proxy_bypass_environment
+import attr
from zope.interface import implementer
from twisted.internet import defer
@@ -22,6 +26,7 @@ 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.http_headers import Headers
from twisted.web.iweb import IAgent
from synapse.http.connectproxyclient import HTTPConnectProxyEndpoint
@@ -31,6 +36,22 @@ logger = logging.getLogger(__name__)
_VALID_URI = re.compile(br"\A[\x21-\x7e]+\Z")
+@attr.s
+class ProxyCredentials:
+ username_password = attr.ib(type=bytes)
+
+ def as_proxy_authorization_value(self) -> bytes:
+ """
+ Return the value for a Proxy-Authorization header (i.e. 'Basic abdef==').
+
+ Returns:
+ A transformation of the authentication string the encoded value for
+ a Proxy-Authorization header.
+ """
+ # Encode as base64 and prepend the authorization type
+ return b"Basic " + base64.encodebytes(self.username_password)
+
+
@implementer(IAgent)
class ProxyAgent(_AgentBase):
"""An Agent implementation which will use an HTTP proxy if one was requested
@@ -39,6 +60,10 @@ class ProxyAgent(_AgentBase):
reactor: twisted reactor to place outgoing
connections.
+ proxy_reactor: twisted reactor to use for connections to the proxy server
+ reactor might have some blacklisting applied (i.e. for DNS queries),
+ but we need unblocked access to the proxy.
+
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
@@ -54,34 +79,56 @@ class ProxyAgent(_AgentBase):
pool (HTTPConnectionPool|None): connection pool to be used. If None, a
non-persistent pool instance will be created.
+
+ use_proxy (bool): Whether proxy settings should be discovered and used
+ from conventional environment variables.
"""
def __init__(
self,
reactor,
+ proxy_reactor=None,
contextFactory=BrowserLikePolicyForHTTPS(),
connectTimeout=None,
bindAddress=None,
pool=None,
- http_proxy=None,
- https_proxy=None,
+ use_proxy=False,
):
_AgentBase.__init__(self, reactor, pool)
+ if proxy_reactor is None:
+ self.proxy_reactor = reactor
+ else:
+ self.proxy_reactor = proxy_reactor
+
self._endpoint_kwargs = {}
if connectTimeout is not None:
self._endpoint_kwargs["timeout"] = connectTimeout
if bindAddress is not None:
self._endpoint_kwargs["bindAddress"] = bindAddress
+ http_proxy = None
+ https_proxy = None
+ no_proxy = None
+ if use_proxy:
+ proxies = getproxies_environment()
+ http_proxy = proxies["http"].encode() if "http" in proxies else None
+ https_proxy = proxies["https"].encode() if "https" in proxies else None
+ no_proxy = proxies["no"] if "no" in proxies else None
+
+ # Parse credentials from https proxy connection string if present
+ self.https_proxy_creds, https_proxy = parse_username_password(https_proxy)
+
self.http_proxy_endpoint = _http_proxy_endpoint(
- http_proxy, reactor, **self._endpoint_kwargs
+ http_proxy, self.proxy_reactor, **self._endpoint_kwargs
)
self.https_proxy_endpoint = _http_proxy_endpoint(
- https_proxy, reactor, **self._endpoint_kwargs
+ https_proxy, self.proxy_reactor, **self._endpoint_kwargs
)
+ self.no_proxy = no_proxy
+
self._policy_for_https = contextFactory
self._reactor = reactor
@@ -129,18 +176,43 @@ class ProxyAgent(_AgentBase):
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:
+ should_skip_proxy = False
+ if self.no_proxy is not None:
+ should_skip_proxy = proxy_bypass_environment(
+ parsed_uri.host.decode(), proxies={"no": self.no_proxy},
+ )
+
+ if (
+ parsed_uri.scheme == b"http"
+ and self.http_proxy_endpoint
+ and not should_skip_proxy
+ ):
# 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:
+ elif (
+ parsed_uri.scheme == b"https"
+ and self.https_proxy_endpoint
+ and not should_skip_proxy
+ ):
+ connect_headers = Headers()
+
+ # Determine whether we need to set Proxy-Authorization headers
+ if self.https_proxy_creds:
+ # Set a Proxy-Authorization header
+ connect_headers.addRawHeader(
+ b"Proxy-Authorization",
+ self.https_proxy_creds.as_proxy_authorization_value(),
+ )
+
endpoint = HTTPConnectProxyEndpoint(
- self._reactor,
+ self.proxy_reactor,
self.https_proxy_endpoint,
parsed_uri.host,
parsed_uri.port,
+ headers=connect_headers,
)
else:
# not using a proxy
@@ -169,12 +241,16 @@ class ProxyAgent(_AgentBase):
)
-def _http_proxy_endpoint(proxy, reactor, **kwargs):
+def _http_proxy_endpoint(proxy: Optional[bytes], reactor, **kwargs):
"""Parses an http proxy setting and returns an endpoint for the proxy
Args:
- proxy (bytes|None): the proxy setting
+ proxy: the proxy setting in the form: [<username>:<password>@]<host>[:<port>]
+ Note that compared to other apps, this function currently lacks support
+ for specifying a protocol schema (i.e. protocol://...).
+
reactor: reactor to be used to connect to the proxy
+
kwargs: other args to be passed to HostnameEndpoint
Returns:
@@ -184,16 +260,43 @@ def _http_proxy_endpoint(proxy, reactor, **kwargs):
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.
-
+ # Parse the connection string
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...
+def parse_username_password(proxy: bytes) -> Tuple[Optional[ProxyCredentials], bytes]:
+ """
+ Parses the username and password from a proxy declaration e.g
+ username:password@hostname:port.
+
+ Args:
+ proxy: The proxy connection string.
+
+ Returns
+ An instance of ProxyCredentials and the proxy connection string with any credentials
+ stripped, i.e u:p@host:port -> host:port. If no credentials were found, the
+ ProxyCredentials instance is replaced with None.
+ """
+ if proxy and b"@" in proxy:
+ # We use rsplit here as the password could contain an @ character
+ credentials, proxy_without_credentials = proxy.rsplit(b"@", 1)
+ return ProxyCredentials(credentials), proxy_without_credentials
+
+ return None, proxy
+
+
+def parse_host_port(hostport: bytes, default_port: int = None) -> Tuple[bytes, int]:
+ """
+ Parse the hostname and port from a proxy connection byte string.
+
+ Args:
+ hostport: The proxy connection string. Must be in the form 'host[:port]'.
+ default_port: The default port to return if one is not found in `hostport`.
+
+ Returns:
+ A tuple containing the hostname and port. Uses `default_port` if one was not found.
+ """
if b":" in hostport:
host, port = hostport.rsplit(b":", 1)
try:
|
