text: # -*- coding: utf-8 -*-
  
  """
  requests.adapters
  ~~~~~~~~~~~~~~~~~
  
  This module contains the transport adapters that Requests uses to define
  and maintain connections.
  """
  
  import os.path
  import socket
  
  from pip._vendor.urllib3.poolmanager import PoolManager, proxy_from_url
  from pip._vendor.urllib3.response import HTTPResponse
  from pip._vendor.urllib3.util import Timeout as TimeoutSauce
  from pip._vendor.urllib3.util.retry import Retry
  from pip._vendor.urllib3.exceptions import ClosedPoolError
  from pip._vendor.urllib3.exceptions import ConnectTimeoutError
  from pip._vendor.urllib3.exceptions import HTTPError as _HTTPError
  from pip._vendor.urllib3.exceptions import MaxRetryError
  from pip._vendor.urllib3.exceptions import NewConnectionError
  from pip._vendor.urllib3.exceptions import ProxyError as _ProxyError
  from pip._vendor.urllib3.exceptions import ProtocolError
  from pip._vendor.urllib3.exceptions import ReadTimeoutError
  from pip._vendor.urllib3.exceptions import SSLError as _SSLError
  from pip._vendor.urllib3.exceptions import ResponseError
  
  from .models import Response
  from .compat import urlparse, basestring
  from .utils import (DEFAULT_CA_BUNDLE_PATH, get_encoding_from_headers,
                      prepend_scheme_if_needed, get_auth_from_url, urldefragauth,
                      select_proxy)
  from .structures import CaseInsensitiveDict
  from .cookies import extract_cookies_to_jar
  from .exceptions import (ConnectionError, ConnectTimeout, ReadTimeout, SSLError,
                           ProxyError, RetryError, InvalidSchema)
  from .auth import _basic_auth_str
  
  try:
      from pip._vendor.urllib3.contrib.socks import SOCKSProxyManager
  except ImportError:
      def SOCKSProxyManager(*args, **kwargs):
          raise InvalidSchema("Missing dependencies for SOCKS support.")
  
  DEFAULT_POOLBLOCK = False
  DEFAULT_POOLSIZE = 10
  DEFAULT_RETRIES = 0
  DEFAULT_POOL_TIMEOUT = None
  
  
  class BaseAdapter(object):
      """The Base Transport Adapter"""
  
      def __init__(self):
          super(BaseAdapter, self).__init__()
  
      def send(self, request, stream=False, timeout=None, verify=True,
               cert=None, proxies=None):
          """Sends PreparedRequest object. Returns Response object.
  
          :param request: The :class:`PreparedRequest <PreparedRequest>` being sent.
          :param stream: (optional) Whether to stream the request content.
          :param timeout: (optional) How long to wait for the server to send
              data before giving up, as a float, or a :ref:`(connect timeout,
              read timeout) <timeouts>` tuple.
          :type timeout: float or tuple
          :param verify: (optional) Either a boolean, in which case it controls whether we verify
              the server's TLS certificate, or a string, in which case it must be a path
              to a CA bundle to use
          :param cert: (optional) Any user-provided SSL certificate to be trusted.
          :param proxies: (optional) The proxies dictionary to apply to the request.
          """
          raise NotImplementedError
  
      def close(self):
          """Cleans up adapter specific items."""
          raise NotImplementedError
  
  
  class HTTPAdapter(BaseAdapter):
      """The built-in HTTP Adapter for urllib3.
  
      Provides a general-case interface for Requests sessions to contact HTTP and
      HTTPS urls by implementing the Transport Adapter interface. This class will
      usually be created by the :class:`Session <Session>` class under the
      covers.
  
      :param pool_connections: The number of urllib3 connection pools to cache.
      :param pool_maxsize: The maximum number of connections to save in the pool.
      :param max_retries: The maximum number of retries each connection
          should attempt. Note, this applies only to failed DNS lookups, socket
          connections and connection timeouts, never to requests where data has
          made it to the server. By default, Requests does not retry failed
          connections. If you need granular control over the conditions under
          which we retry a request, import urllib3's ``Retry`` class and pass
          that instead.
      :param pool_block: Whether the connection pool should block for connections.
  
      Usage::
  
        >>> import requests
        >>> s = requests.Session()
        >>> a = requests.adapters.HTTPAdapter(max_retries=3)
        >>> s.mount('http://', a)
      """
      __attrs__ = ['max_retries', 'config', '_pool_connections', '_pool_maxsize',
                   '_pool_block']
  
      def __init__(self, pool_connections=DEFAULT_POOLSIZE,
                   pool_maxsize=DEFAULT_POOLSIZE, max_retries=DEFAULT_RETRIES,
                   pool_block=DEFAULT_POOLBLOCK):
          if max_retries == DEFAULT_RETRIES:
              self.max_retries = Retry(0, read=False)
          else:
              self.max_retries = Retry.from_int(max_retries)
          self.config = {}
          self.proxy_manager = {}
  
          super(HTTPAdapter, self).__init__()
  
          self._pool_connections = pool_connections
          self._pool_maxsize = pool_maxsize
          self._pool_block = pool_block
  
          self.init_poolmanager(pool_connections, pool_maxsize, block=pool_block)
  
      def __getstate__(self):
          return dict((attr, getattr(self, attr, None)) for attr in
                      self.__attrs__)
  
      def __setstate__(self, state):
          # Can't handle by adding 'proxy_manager' to self.__attrs__ because
          # self.poolmanager uses a lambda function, which isn't pickleable.
          self.proxy_manager = {}
          self.config = {}
  
          for attr, value in state.items():
              setattr(self, attr, value)
  
          self.init_poolmanager(self._pool_connections, self._pool_maxsize,
                                block=self._pool_block)
  
      def init_poolmanager(self, connections, maxsize, block=DEFAULT_POOLBLOCK, **pool_kwargs):
          """Initializes a urllib3 PoolManager.
  
          This method should not be called from user code, and is only
          exposed for use when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          :param connections: The number of urllib3 connection pools to cache.
          :param maxsize: The maximum number of connections to save in the pool.
          :param block: Block when no free connections are available.
          :param pool_kwargs: Extra keyword arguments used to initialize the Pool Manager.
          """
          # save these values for pickling
          self._pool_connections = connections
          self._pool_maxsize = maxsize
          self._pool_block = block
  
          self.poolmanager = PoolManager(num_pools=connections, maxsize=maxsize,
                                         block=block, strict=True, **pool_kwargs)
  
      def proxy_manager_for(self, proxy, **proxy_kwargs):
          """Return urllib3 ProxyManager for the given proxy.
  
          This method should not be called from user code, and is only
          exposed for use when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          :param proxy: The proxy to return a urllib3 ProxyManager for.
          :param proxy_kwargs: Extra keyword arguments used to configure the Proxy Manager.
          :returns: ProxyManager
          :rtype: urllib3.ProxyManager
          """
          if proxy in self.proxy_manager:
              manager = self.proxy_manager[proxy]
          elif proxy.lower().startswith('socks'):
              username, password = get_auth_from_url(proxy)
              manager = self.proxy_manager[proxy] = SOCKSProxyManager(
                  proxy,
                  username=username,
                  password=password,
                  num_pools=self._pool_connections,
                  maxsize=self._pool_maxsize,
                  block=self._pool_block,
                  **proxy_kwargs
              )
          else:
              proxy_headers = self.proxy_headers(proxy)
              manager = self.proxy_manager[proxy] = proxy_from_url(
                  proxy,
                  proxy_headers=proxy_headers,
                  num_pools=self._pool_connections,
                  maxsize=self._pool_maxsize,
                  block=self._pool_block,
                  **proxy_kwargs)
  
          return manager
  
      def cert_verify(self, conn, url, verify, cert):
          """Verify a SSL certificate. This method should not be called from user
          code, and is only exposed for use when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          :param conn: The urllib3 connection object associated with the cert.
          :param url: The requested URL.
          :param verify: Either a boolean, in which case it controls whether we verify
              the server's TLS certificate, or a string, in which case it must be a path
              to a CA bundle to use
          :param cert: The SSL certificate to verify.
          """
          if url.lower().startswith('https') and verify:
  
              cert_loc = None
  
              # Allow self-specified cert location.
              if verify is not True:
                  cert_loc = verify
  
              if not cert_loc:
                  cert_loc = DEFAULT_CA_BUNDLE_PATH
  
              if not cert_loc or not os.path.exists(cert_loc):
                  raise IOError("Could not find a suitable TLS CA certificate bundle, "
                                "invalid path: {0}".format(cert_loc))
  
              conn.cert_reqs = 'CERT_REQUIRED'
  
              if not os.path.isdir(cert_loc):
                  conn.ca_certs = cert_loc
              else:
                  conn.ca_cert_dir = cert_loc
          else:
              conn.cert_reqs = 'CERT_NONE'
              conn.ca_certs = None
              conn.ca_cert_dir = None
  
          if cert:
              if not isinstance(cert, basestring):
                  conn.cert_file = cert[0]
                  conn.key_file = cert[1]
              else:
                  conn.cert_file = cert
                  conn.key_file = None
              if conn.cert_file and not os.path.exists(conn.cert_file):
                  raise IOError("Could not find the TLS certificate file, "
                                "invalid path: {0}".format(conn.cert_file))
              if conn.key_file and not os.path.exists(conn.key_file):
                  raise IOError("Could not find the TLS key file, "
                                "invalid path: {0}".format(conn.key_file))
  
      def build_response(self, req, resp):
          """Builds a :class:`Response <requests.Response>` object from a urllib3
          response. This should not be called from user code, and is only exposed
          for use when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`
  
          :param req: The :class:`PreparedRequest <PreparedRequest>` used to generate the response.
          :param resp: The urllib3 response object.
          :rtype: requests.Response
          """
          response = Response()
  
          # Fallback to None if there's no status_code, for whatever reason.
          response.status_code = getattr(resp, 'status', None)
  
          # Make headers case-insensitive.
          response.headers = CaseInsensitiveDict(getattr(resp, 'headers', {}))
  
          # Set encoding.
          response.encoding = get_encoding_from_headers(response.headers)
          response.raw = resp
          response.reason = response.raw.reason
  
          if isinstance(req.url, bytes):
              response.url = req.url.decode('utf-8')
          else:
              response.url = req.url
  
          # Add new cookies from the server.
          extract_cookies_to_jar(response.cookies, req, resp)
  
          # Give the Response some context.
          response.request = req
          response.connection = self
  
          return response
  
      def get_connection(self, url, proxies=None):
          """Returns a urllib3 connection for the given URL. This should not be
          called from user code, and is only exposed for use when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          :param url: The URL to connect to.
          :param proxies: (optional) A Requests-style dictionary of proxies used on this request.
          :rtype: urllib3.ConnectionPool
          """
          proxy = select_proxy(url, proxies)
  
          if proxy:
              proxy = prepend_scheme_if_needed(proxy, 'http')
              proxy_manager = self.proxy_manager_for(proxy)
              conn = proxy_manager.connection_from_url(url)
          else:
              # Only scheme should be lower case
              parsed = urlparse(url)
              url = parsed.geturl()
              conn = self.poolmanager.connection_from_url(url)
  
          return conn
  
      def close(self):
          """Disposes of any internal state.
  
          Currently, this closes the PoolManager and any active ProxyManager,
          which closes any pooled connections.
          """
          self.poolmanager.clear()
          for proxy in self.proxy_manager.values():
              proxy.clear()
  
      def request_url(self, request, proxies):
          """Obtain the url to use when making the final request.
  
          If the message is being sent through a HTTP proxy, the full URL has to
          be used. Otherwise, we should only use the path portion of the URL.
  
          This should not be called from user code, and is only exposed for use
          when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          :param request: The :class:`PreparedRequest <PreparedRequest>` being sent.
          :param proxies: A dictionary of schemes or schemes and hosts to proxy URLs.
          :rtype: str
          """
          proxy = select_proxy(request.url, proxies)
          scheme = urlparse(request.url).scheme
  
          is_proxied_http_request = (proxy and scheme != 'https')
          using_socks_proxy = False
          if proxy:
              proxy_scheme = urlparse(proxy).scheme.lower()
              using_socks_proxy = proxy_scheme.startswith('socks')
  
          url = request.path_url
          if is_proxied_http_request and not using_socks_proxy:
              url = urldefragauth(request.url)
  
          return url
  
      def add_headers(self, request, **kwargs):
          """Add any headers needed by the connection. As of v2.0 this does
          nothing by default, but is left for overriding by users that subclass
          the :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          This should not be called from user code, and is only exposed for use
          when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          :param request: The :class:`PreparedRequest <PreparedRequest>` to add headers to.
          :param kwargs: The keyword arguments from the call to send().
          """
          pass
  
      def proxy_headers(self, proxy):
          """Returns a dictionary of the headers to add to any request sent
          through a proxy. This works with urllib3 magic to ensure that they are
          correctly sent to the proxy, rather than in a tunnelled request if
          CONNECT is being used.
  
          This should not be called from user code, and is only exposed for use
          when subclassing the
          :class:`HTTPAdapter <requests.adapters.HTTPAdapter>`.
  
          :param proxies: The url of the proxy being used for this request.
          :rtype: dict
          """
          headers = {}
          username, password = get_auth_from_url(proxy)
  
          if username:
              headers['Proxy-Authorization'] = _basic_auth_str(username,
                                                               password)
  
          return headers
  
      def send(self, request, stream=False, timeout=None, verify=True, cert=None, proxies=None):
          """Sends PreparedRequest object. Returns Response object.
  
          :param request: The :class:`PreparedRequest <PreparedRequest>` being sent.
          :param stream: (optional) Whether to stream the request content.
          :param timeout: (optional) How long to wait for the server to send
              data before giving up, as a float, or a :ref:`(connect timeout,
              read timeout) <timeouts>` tuple.
          :type timeout: float or tuple or urllib3 Timeout object
          :param verify: (optional) Either a boolean, in which case it controls whether
              we verify the server's TLS certificate, or a string, in which case it
              must be a path to a CA bundle to use
          :param cert: (optional) Any user-provided SSL certificate to be trusted.
          :param proxies: (optional) The proxies dictionary to apply to the request.
          :rtype: requests.Response
          """
  
          conn = self.get_connection(request.url, proxies)
  
          self.cert_verify(conn, request.url, verify, cert)
          url = self.request_url(request, proxies)
          self.add_headers(request)
  
          chunked = not (request.body is None or 'Content-Length' in request.headers)
  
          if isinstance(timeout, tuple):
              try:
                  connect, read = timeout
                  timeout = TimeoutSauce(connect=connect, read=read)
              except ValueError as e:
                  # this may raise a string formatting error.
                  err = ("Invalid timeout {0}. Pass a (connect, read) "
                         "timeout tuple, or a single float to set "
                         "both timeouts to the same value".format(timeout))
                  raise ValueError(err)
          elif isinstance(timeout, TimeoutSauce):
              pass
          else:
              timeout = TimeoutSauce(connect=timeout, read=timeout)
  
          try:
              if not chunked:
                  resp = conn.urlopen(
                      method=request.method,
                      url=url,
                      body=request.body,
                      headers=request.headers,
                      redirect=False,
                      assert_same_host=False,
                      preload_content=False,
                      decode_content=False,
                      retries=self.max_retries,
                      timeout=timeout
                  )
  
              # Send the request.
              else:
                  if hasattr(conn, 'proxy_pool'):
                      conn = conn.proxy_pool
  
                  low_conn = conn._get_conn(timeout=DEFAULT_POOL_TIMEOUT)
  
                  try:
                      low_conn.putrequest(request.method,
                                          url,
                                          skip_accept_encoding=True)
  
                      for header, value in request.headers.items():
                          low_conn.putheader(header, value)
  
                      low_conn.endheaders()
  
                      for i in request.body:
                          low_conn.send(hex(len(i))[2:].encode('utf-8'))
                          low_conn.send(b'\r\n')
                          low_conn.send(i)
                          low_conn.send(b'\r\n')
                      low_conn.send(b'0\r\n\r\n')
  
                      # Receive the response from the server
                      try:
                          # For Python 2.7+ versions, use buffering of HTTP
                          # responses
                          r = low_conn.getresponse(buffering=True)
                      except TypeError:
                          # For compatibility with Python 2.6 versions and back
                          r = low_conn.getresponse()
  
                      resp = HTTPResponse.from_httplib(
                          r,
                          pool=conn,
                          connection=low_conn,
                          preload_content=False,
                          decode_content=False
                      )
                  except:
                      # If we hit any problems here, clean up the connection.
                      # Then, reraise so that we can handle the actual exception.
                      low_conn.close()
                      raise
  
          except (ProtocolError, socket.error) as err:
              raise ConnectionError(err, request=request)
  
          except MaxRetryError as e:
              if isinstance(e.reason, ConnectTimeoutError):
                  # TODO: Remove this in 3.0.0: see #2811
                  if not isinstance(e.reason, NewConnectionError):
                      raise ConnectTimeout(e, request=request)
  
              if isinstance(e.reason, ResponseError):
                  raise RetryError(e, request=request)
  
              if isinstance(e.reason, _ProxyError):
                  raise ProxyError(e, request=request)
  
              if isinstance(e.reason, _SSLError):
                  # This branch is for urllib3 v1.22 and later.
                  raise SSLError(e, request=request)
  
              raise ConnectionError(e, request=request)
  
          except ClosedPoolError as e:
              raise ConnectionError(e, request=request)
  
          except _ProxyError as e:
              raise ProxyError(e)
  
          except (_SSLError, _HTTPError) as e:
              if isinstance(e, _SSLError):
                  # This branch is for urllib3 versions earlier than v1.22
                  raise SSLError(e, request=request)
              elif isinstance(e, ReadTimeoutError):
                  raise ReadTimeout(e, request=request)
              else:
                  raise
  
          return self.build_response(request, resp)
  