text: from __future__ import absolute_import
  import errno
  import logging
  import sys
  import warnings
  
  from socket import error as SocketError, timeout as SocketTimeout
  import socket
  
  try:  # Python 3
      from queue import LifoQueue, Empty, Full
  except ImportError:
      from Queue import LifoQueue, Empty, Full
      # Queue is imported for side effects on MS Windows
      import Queue as _unused_module_Queue  # noqa: unused
  
  
  from .exceptions import (
      ClosedPoolError,
      ProtocolError,
      EmptyPoolError,
      HeaderParsingError,
      HostChangedError,
      LocationValueError,
      MaxRetryError,
      ProxyError,
      ReadTimeoutError,
      SSLError,
      TimeoutError,
      InsecureRequestWarning,
      NewConnectionError,
  )
  from .packages.ssl_match_hostname import CertificateError
  from .packages import six
  from .connection import (
      port_by_scheme,
      DummyConnection,
      HTTPConnection, HTTPSConnection, VerifiedHTTPSConnection,
      HTTPException, BaseSSLError,
  )
  from .request import RequestMethods
  from .response import HTTPResponse
  
  from .util.connection import is_connection_dropped
  from .util.response import assert_header_parsing
  from .util.retry import Retry
  from .util.timeout import Timeout
  from .util.url import get_host, Url
  
  
  xrange = six.moves.xrange
  
  log = logging.getLogger(__name__)
  
  _Default = object()
  
  
  # Pool objects
  class ConnectionPool(object):
      """
      Base class for all connection pools, such as
      :class:`.HTTPConnectionPool` and :class:`.HTTPSConnectionPool`.
      """
  
      scheme = None
      QueueCls = LifoQueue
  
      def __init__(self, host, port=None):
          if not host:
              raise LocationValueError("No host specified.")
  
          self.host = host
          self.port = port
  
      def __str__(self):
          return '%s(host=%r, port=%r)' % (type(self).__name__,
                                           self.host, self.port)
  
      def __enter__(self):
          return self
  
      def __exit__(self, exc_type, exc_val, exc_tb):
          self.close()
          # Return False to re-raise any potential exceptions
          return False
  
      def close():
          """
          Close all pooled connections and disable the pool.
          """
          pass
  
  
  # This is taken from http://hg.python.org/cpython/file/7aaba721ebc0/Lib/socket.py#l252
  _blocking_errnos = set([errno.EAGAIN, errno.EWOULDBLOCK])
  
  
  class HTTPConnectionPool(ConnectionPool, RequestMethods):
      """
      Thread-safe connection pool for one host.
  
      :param host:
          Host used for this HTTP Connection (e.g. "localhost"), passed into
          :class:`httplib.HTTPConnection`.
  
      :param port:
          Port used for this HTTP Connection (None is equivalent to 80), passed
          into :class:`httplib.HTTPConnection`.
  
      :param strict:
          Causes BadStatusLine to be raised if the status line can't be parsed
          as a valid HTTP/1.0 or 1.1 status line, passed into
          :class:`httplib.HTTPConnection`.
  
          .. note::
             Only works in Python 2. This parameter is ignored in Python 3.
  
      :param timeout:
          Socket timeout in seconds for each individual connection. This can
          be a float or integer, which sets the timeout for the HTTP request,
          or an instance of :class:`urllib3.util.Timeout` which gives you more
          fine-grained control over request timeouts. After the constructor has
          been parsed, this is always a `urllib3.util.Timeout` object.
  
      :param maxsize:
          Number of connections to save that can be reused. More than 1 is useful
          in multithreaded situations. If ``block`` is set to False, more
          connections will be created but they will not be saved once they've
          been used.
  
      :param block:
          If set to True, no more than ``maxsize`` connections will be used at
          a time. When no free connections are available, the call will block
          until a connection has been released. This is a useful side effect for
          particular multithreaded situations where one does not want to use more
          than maxsize connections per host to prevent flooding.
  
      :param headers:
          Headers to include with all requests, unless other headers are given
          explicitly.
  
      :param retries:
          Retry configuration to use by default with requests in this pool.
  
      :param _proxy:
          Parsed proxy URL, should not be used directly, instead, see
          :class:`urllib3.connectionpool.ProxyManager`"
  
      :param _proxy_headers:
          A dictionary with proxy headers, should not be used directly,
          instead, see :class:`urllib3.connectionpool.ProxyManager`"
  
      :param \**conn_kw:
          Additional parameters are used to create fresh :class:`urllib3.connection.HTTPConnection`,
          :class:`urllib3.connection.HTTPSConnection` instances.
      """
  
      scheme = 'http'
      ConnectionCls = HTTPConnection
  
      def __init__(self, host, port=None, strict=False,
                   timeout=Timeout.DEFAULT_TIMEOUT, maxsize=1, block=False,
                   headers=None, retries=None,
                   _proxy=None, _proxy_headers=None,
                   **conn_kw):
          ConnectionPool.__init__(self, host, port)
          RequestMethods.__init__(self, headers)
  
          self.strict = strict
  
          if not isinstance(timeout, Timeout):
              timeout = Timeout.from_float(timeout)
  
          if retries is None:
              retries = Retry.DEFAULT
  
          self.timeout = timeout
          self.retries = retries
  
          self.pool = self.QueueCls(maxsize)
          self.block = block
  
          self.proxy = _proxy
          self.proxy_headers = _proxy_headers or {}
  
          # Fill the queue up so that doing get() on it will block properly
          for _ in xrange(maxsize):
              self.pool.put(None)
  
          # These are mostly for testing and debugging purposes.
          self.num_connections = 0
          self.num_requests = 0
          self.conn_kw = conn_kw
  
          if self.proxy:
              # Enable Nagle's algorithm for proxies, to avoid packet fragmentation.
              # We cannot know if the user has added default socket options, so we cannot replace the
              # list.
              self.conn_kw.setdefault('socket_options', [])
  
      def _new_conn(self):
          """
          Return a fresh :class:`HTTPConnection`.
          """
          self.num_connections += 1
          log.info("Starting new HTTP connection (%d): %s" %
                   (self.num_connections, self.host))
  
          conn = self.ConnectionCls(host=self.host, port=self.port,
                                    timeout=self.timeout.connect_timeout,
                                    strict=self.strict, **self.conn_kw)
          return conn
  
      def _get_conn(self, timeout=None):
          """
          Get a connection. Will return a pooled connection if one is available.
  
          If no connections are available and :prop:`.block` is ``False``, then a
          fresh connection is returned.
  
          :param timeout:
              Seconds to wait before giving up and raising
              :class:`urllib3.exceptions.EmptyPoolError` if the pool is empty and
              :prop:`.block` is ``True``.
          """
          conn = None
          try:
              conn = self.pool.get(block=self.block, timeout=timeout)
  
          except AttributeError:  # self.pool is None
              raise ClosedPoolError(self, "Pool is closed.")
  
          except Empty:
              if self.block:
                  raise EmptyPoolError(self,
                                       "Pool reached maximum size and no more "
                                       "connections are allowed.")
              pass  # Oh well, we'll create a new connection then
  
          # If this is a persistent connection, check if it got disconnected
          if conn and is_connection_dropped(conn):
              log.info("Resetting dropped connection: %s" % self.host)
              conn.close()
              if getattr(conn, 'auto_open', 1) == 0:
                  # This is a proxied connection that has been mutated by
                  # httplib._tunnel() and cannot be reused (since it would
                  # attempt to bypass the proxy)
                  conn = None
  
          return conn or self._new_conn()
  
      def _put_conn(self, conn):
          """
          Put a connection back into the pool.
  
          :param conn:
              Connection object for the current host and port as returned by
              :meth:`._new_conn` or :meth:`._get_conn`.
  
          If the pool is already full, the connection is closed and discarded
          because we exceeded maxsize. If connections are discarded frequently,
          then maxsize should be increased.
  
          If the pool is closed, then the connection will be closed and discarded.
          """
          try:
              self.pool.put(conn, block=False)
              return  # Everything is dandy, done.
          except AttributeError:
              # self.pool is None.
              pass
          except Full:
              # This should never happen if self.block == True
              log.warning(
                  "Connection pool is full, discarding connection: %s" %
                  self.host)
  
          # Connection never got put back into the pool, close it.
          if conn:
              conn.close()
  
      def _validate_conn(self, conn):
          """
          Called right before a request is made, after the socket is created.
          """
          pass
  
      def _prepare_proxy(self, conn):
          # Nothing to do for HTTP connections.
          pass
  
      def _get_timeout(self, timeout):
          """ Helper that always returns a :class:`urllib3.util.Timeout` """
          if timeout is _Default:
              return self.timeout.clone()
  
          if isinstance(timeout, Timeout):
              return timeout.clone()
          else:
              # User passed us an int/float. This is for backwards compatibility,
              # can be removed later
              return Timeout.from_float(timeout)
  
      def _raise_timeout(self, err, url, timeout_value):
          """Is the error actually a timeout? Will raise a ReadTimeout or pass"""
  
          if isinstance(err, SocketTimeout):
              raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value)
  
          # See the above comment about EAGAIN in Python 3. In Python 2 we have
          # to specifically catch it and throw the timeout error
          if hasattr(err, 'errno') and err.errno in _blocking_errnos:
              raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value)
  
          # Catch possible read timeouts thrown as SSL errors. If not the
          # case, rethrow the original. We need to do this because of:
          # http://bugs.python.org/issue10272
          if 'timed out' in str(err) or 'did not complete (read)' in str(err):  # Python 2.6
              raise ReadTimeoutError(self, url, "Read timed out. (read timeout=%s)" % timeout_value)
  
      def _make_request(self, conn, method, url, timeout=_Default,
                        **httplib_request_kw):
          """
          Perform a request on a given urllib connection object taken from our
          pool.
  
          :param conn:
              a connection from one of our connection pools
  
          :param timeout:
              Socket timeout in seconds for the request. This can be a
              float or integer, which will set the same timeout value for
              the socket connect and the socket read, or an instance of
              :class:`urllib3.util.Timeout`, which gives you more fine-grained
              control over your timeouts.
          """
          self.num_requests += 1
  
          timeout_obj = self._get_timeout(timeout)
          timeout_obj.start_connect()
          conn.timeout = timeout_obj.connect_timeout
  
          # Trigger any extra validation we need to do.
          try:
              self._validate_conn(conn)
          except (SocketTimeout, BaseSSLError) as e:
              # Py2 raises this as a BaseSSLError, Py3 raises it as socket timeout.
              self._raise_timeout(err=e, url=url, timeout_value=conn.timeout)
              raise
  
          # conn.request() calls httplib.*.request, not the method in
          # urllib3.request. It also calls makefile (recv) on the socket.
          conn.request(method, url, **httplib_request_kw)
  
          # Reset the timeout for the recv() on the socket
          read_timeout = timeout_obj.read_timeout
  
          # App Engine doesn't have a sock attr
          if getattr(conn, 'sock', None):
              # In Python 3 socket.py will catch EAGAIN and return None when you
              # try and read into the file pointer created by http.client, which
              # instead raises a BadStatusLine exception. Instead of catching
              # the exception and assuming all BadStatusLine exceptions are read
              # timeouts, check for a zero timeout before making the request.
              if read_timeout == 0:
                  raise ReadTimeoutError(
                      self, url, "Read timed out. (read timeout=%s)" % read_timeout)
              if read_timeout is Timeout.DEFAULT_TIMEOUT:
                  conn.sock.settimeout(socket.getdefaulttimeout())
              else:  # None or a value
                  conn.sock.settimeout(read_timeout)
  
          # Receive the response from the server
          try:
              try:  # Python 2.7, use buffering of HTTP responses
                  httplib_response = conn.getresponse(buffering=True)
              except TypeError:  # Python 2.6 and older
                  httplib_response = conn.getresponse()
          except (SocketTimeout, BaseSSLError, SocketError) as e:
              self._raise_timeout(err=e, url=url, timeout_value=read_timeout)
              raise
  
          # AppEngine doesn't have a version attr.
          http_version = getattr(conn, '_http_vsn_str', 'HTTP/?')
          log.debug("\"%s %s %s\" %s %s" % (method, url, http_version,
                                            httplib_response.status,
                                            httplib_response.length))
  
          try:
              assert_header_parsing(httplib_response.msg)
          except HeaderParsingError as hpe:  # Platform-specific: Python 3
              log.warning(
                  'Failed to parse headers (url=%s): %s',
                  self._absolute_url(url), hpe, exc_info=True)
  
          return httplib_response
  
      def _absolute_url(self, path):
          return Url(scheme=self.scheme, host=self.host, port=self.port, path=path).url
  
      def close(self):
          """
          Close all pooled connections and disable the pool.
          """
          # Disable access to the pool
          old_pool, self.pool = self.pool, None
  
          try:
              while True:
                  conn = old_pool.get(block=False)
                  if conn:
                      conn.close()
  
          except Empty:
              pass  # Done.
  
      def is_same_host(self, url):
          """
          Check if the given ``url`` is a member of the same host as this
          connection pool.
          """
          if url.startswith('/'):
              return True
  
          # TODO: Add optional support for socket.gethostbyname checking.
          scheme, host, port = get_host(url)
  
          # Use explicit default port for comparison when none is given
          if self.port and not port:
              port = port_by_scheme.get(scheme)
          elif not self.port and port == port_by_scheme.get(scheme):
              port = None
  
          return (scheme, host, port) == (self.scheme, self.host, self.port)
  
      def urlopen(self, method, url, body=None, headers=None, retries=None,
                  redirect=True, assert_same_host=True, timeout=_Default,
                  pool_timeout=None, release_conn=None, **response_kw):
          """
          Get a connection from the pool and perform an HTTP request. This is the
          lowest level call for making a request, so you'll need to specify all
          the raw details.
  
          .. note::
  
             More commonly, it's appropriate to use a convenience method provided
             by :class:`.RequestMethods`, such as :meth:`request`.
  
          .. note::
  
             `release_conn` will only behave as expected if
             `preload_content=False` because we want to make
             `preload_content=False` the default behaviour someday soon without
             breaking backwards compatibility.
  
          :param method:
              HTTP request method (such as GET, POST, PUT, etc.)
  
          :param body:
              Data to send in the request body (useful for creating
              POST requests, see HTTPConnectionPool.post_url for
              more convenience).
  
          :param headers:
              Dictionary of custom headers to send, such as User-Agent,
              If-None-Match, etc. If None, pool headers are used. If provided,
              these headers completely replace any pool-specific headers.
  
          :param retries:
              Configure the number of retries to allow before raising a
              :class:`~urllib3.exceptions.MaxRetryError` exception.
  
              Pass ``None`` to retry until you receive a response. Pass a
              :class:`~urllib3.util.retry.Retry` object for fine-grained control
              over different types of retries.
              Pass an integer number to retry connection errors that many times,
              but no other types of errors. Pass zero to never retry.
  
              If ``False``, then retries are disabled and any exception is raised
              immediately. Also, instead of raising a MaxRetryError on redirects,
              the redirect response will be returned.
  
          :type retries: :class:`~urllib3.util.retry.Retry`, False, or an int.
  
          :param redirect:
              If True, automatically handle redirects (status codes 301, 302,
              303, 307, 308). Each redirect counts as a retry. Disabling retries
              will disable redirect, too.
  
          :param assert_same_host:
              If ``True``, will make sure that the host of the pool requests is
              consistent else will raise HostChangedError. When False, you can
              use the pool on an HTTP proxy and request foreign hosts.
  
          :param timeout:
              If specified, overrides the default timeout for this one
              request. It may be a float (in seconds) or an instance of
              :class:`urllib3.util.Timeout`.
  
          :param pool_timeout:
              If set and the pool is set to block=True, then this method will
              block for ``pool_timeout`` seconds and raise EmptyPoolError if no
              connection is available within the time period.
  
          :param release_conn:
              If False, then the urlopen call will not release the connection
              back into the pool once a response is received (but will release if
              you read the entire contents of the response such as when
              `preload_content=True`). This is useful if you're not preloading
              the response's content immediately. You will need to call
              ``r.release_conn()`` on the response ``r`` to return the connection
              back into the pool. If None, it takes the value of
              ``response_kw.get('preload_content', True)``.
  
          :param \**response_kw:
              Additional parameters are passed to
              :meth:`urllib3.response.HTTPResponse.from_httplib`
          """
          if headers is None:
              headers = self.headers
  
          if not isinstance(retries, Retry):
              retries = Retry.from_int(retries, redirect=redirect, default=self.retries)
  
          if release_conn is None:
              release_conn = response_kw.get('preload_content', True)
  
          # Check host
          if assert_same_host and not self.is_same_host(url):
              raise HostChangedError(self, url, retries)
  
          conn = None
  
          # Merge the proxy headers. Only do this in HTTP. We have to copy the
          # headers dict so we can safely change it without those changes being
          # reflected in anyone else's copy.
          if self.scheme == 'http':
              headers = headers.copy()
              headers.update(self.proxy_headers)
  
          # Must keep the exception bound to a separate variable or else Python 3
          # complains about UnboundLocalError.
          err = None
  
          try:
              # Request a connection from the queue.
              timeout_obj = self._get_timeout(timeout)
              conn = self._get_conn(timeout=pool_timeout)
  
              conn.timeout = timeout_obj.connect_timeout
  
              is_new_proxy_conn = self.proxy is not None and not getattr(conn, 'sock', None)
              if is_new_proxy_conn:
                  self._prepare_proxy(conn)
  
              # Make the request on the httplib connection object.
              httplib_response = self._make_request(conn, method, url,
                                                    timeout=timeout_obj,
                                                    body=body, headers=headers)
  
              # If we're going to release the connection in ``finally:``, then
              # the request doesn't need to know about the connection. Otherwise
              # it will also try to release it and we'll have a double-release
              # mess.
              response_conn = not release_conn and conn
  
              # Import httplib's response into our own wrapper object
              response = HTTPResponse.from_httplib(httplib_response,
                                                   pool=self,
                                                   connection=response_conn,
                                                   **response_kw)
  
              # else:
              #     The connection will be put back into the pool when
              #     ``response.release_conn()`` is called (implicitly by
              #     ``response.read()``)
  
          except Empty:
              # Timed out by queue.
              raise EmptyPoolError(self, "No pool connections are available.")
  
          except (BaseSSLError, CertificateError) as e:
              # Close the connection. If a connection is reused on which there
              # was a Certificate error, the next request will certainly raise
              # another Certificate error.
              conn = conn and conn.close()
              release_conn = True
              raise SSLError(e)
  
          except SSLError:
              # Treat SSLError separately from BaseSSLError to preserve
              # traceback.
              conn = conn and conn.close()
              release_conn = True
              raise
  
          except (TimeoutError, HTTPException, SocketError, ProtocolError) as e:
              # Discard the connection for these exceptions. It will be
              # be replaced during the next _get_conn() call.
              conn = conn and conn.close()
              release_conn = True
  
              if isinstance(e, (SocketError, NewConnectionError)) and self.proxy:
                  e = ProxyError('Cannot connect to proxy.', e)
              elif isinstance(e, (SocketError, HTTPException)):
                  e = ProtocolError('Connection aborted.', e)
  
              retries = retries.increment(method, url, error=e, _pool=self,
                                          _stacktrace=sys.exc_info()[2])
              retries.sleep()
  
              # Keep track of the error for the retry warning.
              err = e
  
          finally:
              if release_conn:
                  # Put the connection back to be reused. If the connection is
                  # expired then it will be None, which will get replaced with a
                  # fresh connection during _get_conn.
                  self._put_conn(conn)
  
          if not conn:
              # Try again
              log.warning("Retrying (%r) after connection "
                          "broken by '%r': %s" % (retries, err, url))
              return self.urlopen(method, url, body, headers, retries,
                                  redirect, assert_same_host,
                                  timeout=timeout, pool_timeout=pool_timeout,
                                  release_conn=release_conn, **response_kw)
  
          # Handle redirect?
          redirect_location = redirect and response.get_redirect_location()
          if redirect_location:
              if response.status == 303:
                  method = 'GET'
  
              try:
                  retries = retries.increment(method, url, response=response, _pool=self)
              except MaxRetryError:
                  if retries.raise_on_redirect:
                      # Release the connection for this response, since we're not
                      # returning it to be released manually.
                      response.release_conn()
                      raise
                  return response
  
              log.info("Redirecting %s -> %s" % (url, redirect_location))
              return self.urlopen(
                  method, redirect_location, body, headers,
                  retries=retries, redirect=redirect,
                  assert_same_host=assert_same_host,
                  timeout=timeout, pool_timeout=pool_timeout,
                  release_conn=release_conn, **response_kw)
  
          # Check if we should retry the HTTP response.
          if retries.is_forced_retry(method, status_code=response.status):
              retries = retries.increment(method, url, response=response, _pool=self)
              retries.sleep()
              log.info("Forced retry: %s" % url)
              return self.urlopen(
                  method, url, body, headers,
                  retries=retries, redirect=redirect,
                  assert_same_host=assert_same_host,
                  timeout=timeout, pool_timeout=pool_timeout,
                  release_conn=release_conn, **response_kw)
  
          return response
  
  
  class HTTPSConnectionPool(HTTPConnectionPool):
      """
      Same as :class:`.HTTPConnectionPool`, but HTTPS.
  
      When Python is compiled with the :mod:`ssl` module, then
      :class:`.VerifiedHTTPSConnection` is used, which *can* verify certificates,
      instead of :class:`.HTTPSConnection`.
  
      :class:`.VerifiedHTTPSConnection` uses one of ``assert_fingerprint``,
      ``assert_hostname`` and ``host`` in this order to verify connections.
      If ``assert_hostname`` is False, no verification is done.
  
      The ``key_file``, ``cert_file``, ``cert_reqs``, ``ca_certs``,
      ``ca_cert_dir``, and ``ssl_version`` are only used if :mod:`ssl` is
      available and are fed into :meth:`urllib3.util.ssl_wrap_socket` to upgrade
      the connection socket into an SSL socket.
      """
  
      scheme = 'https'
      ConnectionCls = HTTPSConnection
  
      def __init__(self, host, port=None,
                   strict=False, timeout=Timeout.DEFAULT_TIMEOUT, maxsize=1,
                   block=False, headers=None, retries=None,
                   _proxy=None, _proxy_headers=None,
                   key_file=None, cert_file=None, cert_reqs=None,
                   ca_certs=None, ssl_version=None,
                   assert_hostname=None, assert_fingerprint=None,
                   ca_cert_dir=None, **conn_kw):
  
          HTTPConnectionPool.__init__(self, host, port, strict, timeout, maxsize,
                                      block, headers, retries, _proxy, _proxy_headers,
                                      **conn_kw)
  
          if ca_certs and cert_reqs is None:
              cert_reqs = 'CERT_REQUIRED'
  
          self.key_file = key_file
          self.cert_file = cert_file
          self.cert_reqs = cert_reqs
          self.ca_certs = ca_certs
          self.ca_cert_dir = ca_cert_dir
          self.ssl_version = ssl_version
          self.assert_hostname = assert_hostname
          self.assert_fingerprint = assert_fingerprint
  
      def _prepare_conn(self, conn):
          """
          Prepare the ``connection`` for :meth:`urllib3.util.ssl_wrap_socket`
          and establish the tunnel if proxy is used.
          """
  
          if isinstance(conn, VerifiedHTTPSConnection):
              conn.set_cert(key_file=self.key_file,
                            cert_file=self.cert_file,
                            cert_reqs=self.cert_reqs,
                            ca_certs=self.ca_certs,
                            ca_cert_dir=self.ca_cert_dir,
                            assert_hostname=self.assert_hostname,
                            assert_fingerprint=self.assert_fingerprint)
              conn.ssl_version = self.ssl_version
  
          return conn
  
      def _prepare_proxy(self, conn):
          """
          Establish tunnel connection early, because otherwise httplib
          would improperly set Host: header to proxy's IP:port.
          """
          # Python 2.7+
          try:
              set_tunnel = conn.set_tunnel
          except AttributeError:  # Platform-specific: Python 2.6
              set_tunnel = conn._set_tunnel
  
          if sys.version_info <= (2, 6, 4) and not self.proxy_headers:   # Python 2.6.4 and older
              set_tunnel(self.host, self.port)
          else:
              set_tunnel(self.host, self.port, self.proxy_headers)
  
          conn.connect()
  
      def _new_conn(self):
          """
          Return a fresh :class:`httplib.HTTPSConnection`.
          """
          self.num_connections += 1
          log.info("Starting new HTTPS connection (%d): %s"
                   % (self.num_connections, self.host))
  
          if not self.ConnectionCls or self.ConnectionCls is DummyConnection:
              raise SSLError("Can't connect to HTTPS URL because the SSL "
                             "module is not available.")
  
          actual_host = self.host
          actual_port = self.port
          if self.proxy is not None:
              actual_host = self.proxy.host
              actual_port = self.proxy.port
  
          conn = self.ConnectionCls(host=actual_host, port=actual_port,
                                    timeout=self.timeout.connect_timeout,
                                    strict=self.strict, **self.conn_kw)
  
          return self._prepare_conn(conn)
  
      def _validate_conn(self, conn):
          """
          Called right before a request is made, after the socket is created.
          """
          super(HTTPSConnectionPool, self)._validate_conn(conn)
  
          # Force connect early to allow us to validate the connection.
          if not getattr(conn, 'sock', None):  # AppEngine might not have  `.sock`
              conn.connect()
  
          if not conn.is_verified:
              warnings.warn((
                  'Unverified HTTPS request is being made. '
                  'Adding certificate verification is strongly advised. See: '
                  'https://urllib3.readthedocs.org/en/latest/security.html'),
                  InsecureRequestWarning)
  
  
  def connection_from_url(url, **kw):
      """
      Given a url, return an :class:`.ConnectionPool` instance of its host.
  
      This is a shortcut for not having to parse out the scheme, host, and port
      of the url before creating an :class:`.ConnectionPool` instance.
  
      :param url:
          Absolute URL string that must include the scheme. Port is optional.
  
      :param \**kw:
          Passes additional parameters to the constructor of the appropriate
          :class:`.ConnectionPool`. Useful for specifying things like
          timeout, maxsize, headers, etc.
  
      Example::
  
          >>> conn = connection_from_url('http://google.com/')
          >>> r = conn.request('GET', '/')
      """
      scheme, host, port = get_host(url)
      if scheme == 'https':
          return HTTPSConnectionPool(host, port=port, **kw)
      else:
          return HTTPConnectionPool(host, port=port, **kw)
  