Add google-endpoints to third_party/.

third_party/google-endpoints/urllib3/contrib/socks.py

Index: third_party/google-endpoints/urllib3/contrib/socks.py
diff --git a/third_party/google-endpoints/urllib3/contrib/socks.py b/third_party/google-endpoints/urllib3/contrib/socks.py
new file mode 100644
index 0000000000000000000000000000000000000000..39e92fde19b1332a7c90f6b6afe2a69601e9a66d
--- /dev/null
+++ b/third_party/google-endpoints/urllib3/contrib/socks.py
@@ -0,0 +1,188 @@
+# -*- coding: utf-8 -*-
+"""
+This module contains provisional support for SOCKS proxies from within
+urllib3. This module supports SOCKS4 (specifically the SOCKS4A variant) and
+SOCKS5. To enable its functionality, either install PySocks or install this
+module with the ``socks`` extra.
+
+The SOCKS implementation supports the full range of urllib3 features. It also
+supports the following SOCKS features:
+
+- SOCKS4
+- SOCKS4a
+- SOCKS5
+- Usernames and passwords for the SOCKS proxy
+
+Known Limitations:
+
+- Currently PySocks does not support contacting remote websites via literal
+  IPv6 addresses. Any such connection attempt will fail. You must use a domain
+  name.
+- Currently PySocks does not support IPv6 connections to the SOCKS proxy. Any
+  such connection attempt will fail.
+"""
+from __future__ import absolute_import
+
+try:
+    import socks
+except ImportError:
+    import warnings
+    from ..exceptions import DependencyWarning
+
+    warnings.warn((
+        'SOCKS support in urllib3 requires the installation of optional '
+        'dependencies: specifically, PySocks.  For more information, see '
+        'https://urllib3.readthedocs.io/en/latest/contrib.html#socks-proxies'
+        ),
+        DependencyWarning
+    )
+    raise
+
+from socket import error as SocketError, timeout as SocketTimeout
+
+from ..connection import (
+    HTTPConnection, HTTPSConnection
+)
+from ..connectionpool import (
+    HTTPConnectionPool, HTTPSConnectionPool
+)
+from ..exceptions import ConnectTimeoutError, NewConnectionError
+from ..poolmanager import PoolManager
+from ..util.url import parse_url
+
+try:
+    import ssl
+except ImportError:
+    ssl = None
+
+
+class SOCKSConnection(HTTPConnection):
+    """
+    A plain-text HTTP connection that connects via a SOCKS proxy.
+    """
+    def __init__(self, *args, **kwargs):
+        self._socks_options = kwargs.pop('_socks_options')
+        super(SOCKSConnection, self).__init__(*args, **kwargs)
+
+    def _new_conn(self):
+        """
+        Establish a new connection via the SOCKS proxy.
+        """
+        extra_kw = {}
+        if self.source_address:
+            extra_kw['source_address'] = self.source_address
+
+        if self.socket_options:
+            extra_kw['socket_options'] = self.socket_options
+
+        try:
+            conn = socks.create_connection(
+                (self.host, self.port),
+                proxy_type=self._socks_options['socks_version'],
+                proxy_addr=self._socks_options['proxy_host'],
+                proxy_port=self._socks_options['proxy_port'],
+                proxy_username=self._socks_options['username'],
+                proxy_password=self._socks_options['password'],
+                proxy_rdns=self._socks_options['rdns'],
+                timeout=self.timeout,
+                **extra_kw
+            )
+
+        except SocketTimeout as e:
+            raise ConnectTimeoutError(
+                self, "Connection to %s timed out. (connect timeout=%s)" %
+                (self.host, self.timeout))
+
+        except socks.ProxyError as e:
+            # This is fragile as hell, but it seems to be the only way to raise
+            # useful errors here.
+            if e.socket_err:
+                error = e.socket_err
+                if isinstance(error, SocketTimeout):
+                    raise ConnectTimeoutError(
+                        self,
+                        "Connection to %s timed out. (connect timeout=%s)" %
+                        (self.host, self.timeout)
+                    )
+                else:
+                    raise NewConnectionError(
+                        self,
+                        "Failed to establish a new connection: %s" % error
+                    )
+            else:
+                raise NewConnectionError(
+                    self,
+                    "Failed to establish a new connection: %s" % e
+                )
+
+        except SocketError as e:  # Defensive: PySocks should catch all these.
+            raise NewConnectionError(
+                self, "Failed to establish a new connection: %s" % e)
+
+        return conn
+
+
+# We don't need to duplicate the Verified/Unverified distinction from
+# urllib3/connection.py here because the HTTPSConnection will already have been
+# correctly set to either the Verified or Unverified form by that module. This
+# means the SOCKSHTTPSConnection will automatically be the correct type.
+class SOCKSHTTPSConnection(SOCKSConnection, HTTPSConnection):
+    pass
+
+
+class SOCKSHTTPConnectionPool(HTTPConnectionPool):
+    ConnectionCls = SOCKSConnection
+
+
+class SOCKSHTTPSConnectionPool(HTTPSConnectionPool):
+    ConnectionCls = SOCKSHTTPSConnection
+
+
+class SOCKSProxyManager(PoolManager):
+    """
+    A version of the urllib3 ProxyManager that routes connections via the
+    defined SOCKS proxy.
+    """
+    pool_classes_by_scheme = {
+        'http': SOCKSHTTPConnectionPool,
+        'https': SOCKSHTTPSConnectionPool,
+    }
+
+    def __init__(self, proxy_url, username=None, password=None,
+                 num_pools=10, headers=None, **connection_pool_kw):
+        parsed = parse_url(proxy_url)
+
+        if parsed.scheme == 'socks5':
+            socks_version = socks.PROXY_TYPE_SOCKS5
+            rdns = False
+        elif parsed.scheme == 'socks5h':
+            socks_version = socks.PROXY_TYPE_SOCKS5
+            rdns = True
+        elif parsed.scheme == 'socks4':
+            socks_version = socks.PROXY_TYPE_SOCKS4
+            rdns = False
+        elif parsed.scheme == 'socks4a':
+            socks_version = socks.PROXY_TYPE_SOCKS4
+            rdns = True
+        else:
+            raise ValueError(
+                "Unable to determine SOCKS version from %s" % proxy_url
+            )
+
+        self.proxy_url = proxy_url
+
+        socks_options = {
+            'socks_version': socks_version,
+            'proxy_host': parsed.host,
+            'proxy_port': parsed.port,
+            'username': username,
+            'password': password,
+            'rdns': rdns
+        }
+        connection_pool_kw['_socks_options'] = socks_options
+
+        super(SOCKSProxyManager, self).__init__(
+            num_pools, headers, **connection_pool_kw
+        )
+
+        self.pool_classes_by_scheme = SOCKSProxyManager.pool_classes_by_scheme