text: import errno
  import logging
  import queue
  import sys
  import warnings
  from http.client import HTTPResponse as _HttplibHTTPResponse
  from socket import timeout as SocketTimeout
  from types import TracebackType
  from typing import TYPE_CHECKING, Any, Mapping, Optional, Type, TypeVar, Union, overload
  
  from ._request_methods import RequestMethods
  from .connection import (
      _TYPE_BODY,
      BaseSSLError,
      BrokenPipeError,
      DummyConnection,
      HTTPConnection,
      HTTPException,
      HTTPSConnection,
      ProxyConfig,
      VerifiedHTTPSConnection,
      _wrap_proxy_error,
  )
  from .connection import port_by_scheme as port_by_scheme
  from .exceptions import (
      ClosedPoolError,
      EmptyPoolError,
      FullPoolError,
      HeaderParsingError,
      HostChangedError,
      InsecureRequestWarning,
      LocationValueError,
      MaxRetryError,
      NewConnectionError,
      ProtocolError,
      ProxyError,
      ReadTimeoutError,
      SSLError,
      TimeoutError,
  )
  from .response import BaseHTTPResponse, HTTPResponse
  from .util.connection import is_connection_dropped
  from .util.proxy import connection_requires_http_tunnel
  from .util.request import _TYPE_BODY_POSITION, set_file_position
  from .util.response import assert_header_parsing
  from .util.retry import Retry
  from .util.ssl_match_hostname import CertificateError
  from .util.timeout import _DEFAULT_TIMEOUT, _TYPE_DEFAULT, Timeout
  from .util.url import Url, _encode_target
  from .util.url import _normalize_host as normalize_host
  from .util.url import parse_url
  from .util.util import to_str
  
  if TYPE_CHECKING:
      import ssl
  
      from typing_extensions import Literal
  
  log = logging.getLogger(__name__)
  
  _TYPE_TIMEOUT = Union[Timeout, float, _TYPE_DEFAULT]
  
  _SelfT = TypeVar("_SelfT")
  
  
  # Pool objects
  class ConnectionPool:
      """
      Base class for all connection pools, such as
      :class:`.HTTPConnectionPool` and :class:`.HTTPSConnectionPool`.
  
      .. note::
         ConnectionPool.urlopen() does not normalize or percent-encode target URIs
         which is useful if your target server doesn't support percent-encoded
         target URIs.
      """
  
      scheme: Optional[str] = None
      QueueCls = queue.LifoQueue
  
      def __init__(self, host: str, port: Optional[int] = None) -> None:
          if not host:
              raise LocationValueError("No host specified.")
  
          self.host = _normalize_host(host, scheme=self.scheme)
          self._proxy_host = host.lower()
          self.port = port
  
      def __str__(self) -> str:
          return f"{type(self).__name__}(host={self.host!r}, port={self.port!r})"
  
      def __enter__(self: _SelfT) -> _SelfT:
          return self
  
      def __exit__(
          self,
          exc_type: Optional[Type[BaseException]],
          exc_val: Optional[BaseException],
          exc_tb: Optional[TracebackType],
      ) -> "Literal[False]":
          self.close()
          # Return False to re-raise any potential exceptions
          return False
  
      def close(self) -> None:
          """
          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 = {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:`http.client.HTTPConnection`.
  
      :param port:
          Port used for this HTTP Connection (None is equivalent to 80), passed
          into :class:`http.client.HTTPConnection`.
  
      :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.ProxyManager`
  
      :param _proxy_headers:
          A dictionary with proxy headers, should not be used directly,
          instead, see :class:`urllib3.ProxyManager`
  
      :param \\**conn_kw:
          Additional parameters are used to create fresh :class:`urllib3.connection.HTTPConnection`,
          :class:`urllib3.connection.HTTPSConnection` instances.
      """
  
      scheme = "http"
      ConnectionCls: Type[Union[HTTPConnection, HTTPSConnection]] = HTTPConnection
      ResponseCls = HTTPResponse
  
      def __init__(
          self,
          host: str,
          port: Optional[int] = None,
          timeout: Optional[_TYPE_TIMEOUT] = _DEFAULT_TIMEOUT,
          maxsize: int = 1,
          block: bool = False,
          headers: Optional[Mapping[str, str]] = None,
          retries: Optional[Union[Retry, bool, int]] = None,
          _proxy: Optional[Url] = None,
          _proxy_headers: Optional[Mapping[str, str]] = None,
          _proxy_config: Optional[ProxyConfig] = None,
          **conn_kw: Any,
      ):
          ConnectionPool.__init__(self, host, port)
          RequestMethods.__init__(self, headers)
  
          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: Optional[queue.LifoQueue[Any]] = self.QueueCls(maxsize)
          self.block = block
  
          self.proxy = _proxy
          self.proxy_headers = _proxy_headers or {}
          self.proxy_config = _proxy_config
  
          # Fill the queue up so that doing get() on it will block properly
          for _ in range(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", [])
  
              self.conn_kw["proxy"] = self.proxy
              self.conn_kw["proxy_config"] = self.proxy_config
  
      def _new_conn(self) -> HTTPConnection:
          """
          Return a fresh :class:`HTTPConnection`.
          """
          self.num_connections += 1
          log.debug(
              "Starting new HTTP connection (%d): %s:%s",
              self.num_connections,
              self.host,
              self.port or "80",
          )
  
          conn = self.ConnectionCls(
              host=self.host,
              port=self.port,
              timeout=self.timeout.connect_timeout,
              **self.conn_kw,
          )
          return conn
  
      def _get_conn(self, timeout: Optional[float] = None) -> HTTPConnection:
          """
          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
  
          if self.pool is None:
              raise ClosedPoolError(self, "Pool is closed.")
  
          try:
              conn = self.pool.get(block=self.block, timeout=timeout)
  
          except AttributeError:  # self.pool is None
              raise ClosedPoolError(self, "Pool is closed.") from None  # Defensive:
  
          except queue.Empty:
              if self.block:
                  raise EmptyPoolError(
                      self,
                      "Pool is empty and a new connection can't be opened due to blocking mode.",
                  ) from None
              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.debug("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
                  # http.client._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: Optional[HTTPConnection]) -> None:
          """
          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.
          """
          if self.pool is not None:
              try:
                  self.pool.put(conn, block=False)
                  return  # Everything is dandy, done.
              except AttributeError:
                  # self.pool is None.
                  pass
              except queue.Full:
  
                  # Connection never got put back into the pool, close it.
                  if conn:
                      conn.close()
  
                  if self.block:
                      # This should never happen if you got the conn from self._get_conn
                      raise FullPoolError(
                          self,
                          "Pool reached maximum size and no more connections are allowed.",
                      ) from None
  
                  log.warning(
                      "Connection pool is full, discarding connection: %s. Connection pool size: %s",
                      self.host,
                      self.pool.qsize(),
                  )
  
          # Connection never got put back into the pool, close it.
          if conn:
              conn.close()
  
      def _validate_conn(self, conn: HTTPConnection) -> None:
          """
          Called right before a request is made, after the socket is created.
          """
          pass
  
      def _prepare_proxy(self, conn: HTTPConnection) -> None:
          # Nothing to do for HTTP connections.
          pass
  
      def _get_timeout(self, timeout: _TYPE_TIMEOUT) -> Timeout:
          """Helper that always returns a :class:`urllib3.util.Timeout`"""
          if timeout is _DEFAULT_TIMEOUT:
              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: Union[BaseSSLError, OSError, SocketTimeout],
          url: str,
          timeout_value: Optional[_TYPE_TIMEOUT],
      ) -> None:
          """Is the error actually a timeout? Will raise a ReadTimeout or pass"""
  
          if isinstance(err, SocketTimeout):
              raise ReadTimeoutError(
                  self, url, f"Read timed out. (read timeout={timeout_value})"
              ) from err
  
          # See the above comment about EAGAIN in Python 3.
          if hasattr(err, "errno") and err.errno in _blocking_errnos:
              raise ReadTimeoutError(
                  self, url, f"Read timed out. (read timeout={timeout_value})"
              ) from err
  
      def _make_request(
          self,
          conn: HTTPConnection,
          method: str,
          url: str,
          timeout: _TYPE_TIMEOUT = _DEFAULT_TIMEOUT,
          chunked: bool = False,
          **httplib_request_kw: Any,
      ) -> _HttplibHTTPResponse:
          """
          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  # type: ignore[assignment]
  
          try:
              # Trigger any extra validation we need to do.
              try:
                  self._validate_conn(conn)
              except (SocketTimeout, BaseSSLError) as e:
                  self._raise_timeout(err=e, url=url, timeout_value=conn.timeout)
                  raise
  
          # _validate_conn() starts the connection to an HTTPS proxy
          # so we need to wrap errors with 'ProxyError' here too.
          except (
              OSError,
              NewConnectionError,
              TimeoutError,
              BaseSSLError,
              CertificateError,
              SSLError,
          ) as e:
              new_e: Exception = e
              if isinstance(e, (BaseSSLError, CertificateError)):
                  new_e = SSLError(e)
              if isinstance(
                  new_e, (OSError, NewConnectionError, TimeoutError, SSLError)
              ) and (conn and conn._connecting_to_proxy):
                  new_e = _wrap_proxy_error(new_e)
              raise new_e
  
          # conn.request() calls http.client.*.request, not the method in
          # urllib3.request. It also calls makefile (recv) on the socket.
          try:
              if chunked:
                  conn.request_chunked(method, url, **httplib_request_kw)
              else:
                  conn.request(method, url, **httplib_request_kw)
  
          # We are swallowing BrokenPipeError (errno.EPIPE) since the server is
          # legitimately able to close the connection after sending a valid response.
          # With this behaviour, the received response is still readable.
          except BrokenPipeError:
              pass
          except OSError as e:
              # MacOS/Linux
              # EPROTOTYPE is needed on macOS
              # https://erickt.github.io/blog/2014/11/19/adventures-in-debugging-a-potential-osx-kernel-bug/
              if e.errno != errno.EPROTOTYPE:
                  raise
  
          # Reset the timeout for the recv() on the socket
          read_timeout = timeout_obj.read_timeout
  
          if conn.sock:
              # 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, f"Read timed out. (read timeout={read_timeout})"
                  )
              conn.sock.settimeout(read_timeout)
  
          # Receive the response from the server
          try:
              httplib_response = conn.getresponse()
          except (BaseSSLError, OSError) as e:
              self._raise_timeout(err=e, url=url, timeout_value=read_timeout)
              raise
  
          log.debug(
              '%s://%s:%s "%s %s %s" %s %s',
              self.scheme,
              self.host,
              self.port,
              method,
              url,
              # HTTP version
              conn._http_vsn_str,  # type: ignore[attr-defined]
              httplib_response.status,
              httplib_response.length,
          )
  
          try:
              assert_header_parsing(httplib_response.msg)
          except (HeaderParsingError, TypeError) as hpe:
              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: str) -> str:
          return Url(scheme=self.scheme, host=self.host, port=self.port, path=path).url
  
      def close(self) -> None:
          """
          Close all pooled connections and disable the pool.
          """
          if self.pool is None:
              return
          # 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 queue.Empty:
              pass  # Done.
  
      def is_same_host(self, url: str) -> bool:
          """
          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, *_ = parse_url(url)
          scheme = scheme or "http"
          if host is not None:
              host = _normalize_host(host, scheme=scheme)
  
          # 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(  # type: ignore[override]
          self,
          method: str,
          url: str,
          body: Optional[_TYPE_BODY] = None,
          headers: Optional[Mapping[str, str]] = None,
          retries: Optional[Union[Retry, bool, int]] = None,
          redirect: bool = True,
          assert_same_host: bool = True,
          timeout: _TYPE_TIMEOUT = _DEFAULT_TIMEOUT,
          pool_timeout: Optional[int] = None,
          release_conn: Optional[bool] = None,
          chunked: bool = False,
          body_pos: Optional[_TYPE_BODY_POSITION] = None,
          **response_kw: Any,
      ) -> BaseHTTPResponse:
          """
          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 url:
              The URL to perform the request on.
  
          :param body:
              Data to send in the request body, either :class:`str`, :class:`bytes`,
              an iterable of :class:`str`/:class:`bytes`, or a file-like object.
  
          :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 chunked:
              If True, urllib3 will send the body using chunked transfer
              encoding. Otherwise, urllib3 will send the body using the standard
              content-length form. Defaults to False.
  
          :param int body_pos:
              Position to seek to in file-like body in the event of a retry or
              redirect. Typically this won't need to be set because urllib3 will
              auto-populate the value when needed.
  
          :param \\**response_kw:
              Additional parameters are passed to
              :meth:`urllib3.response.HTTPResponse.from_httplib`
          """
  
          parsed_url = parse_url(url)
          destination_scheme = parsed_url.scheme
  
          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)
  
          # Ensure that the URL we're connecting to is properly encoded
          if url.startswith("/"):
              url = to_str(_encode_target(url))
          else:
              url = to_str(parsed_url.url)
  
          conn = None
  
          # Track whether `conn` needs to be released before
          # returning/raising/recursing. Update this variable if necessary, and
          # leave `release_conn` constant throughout the function. That way, if
          # the function recurses, the original value of `release_conn` will be
          # passed down into the recursive call, and its value will be respected.
          #
          # See issue #651 [1] for details.
          #
          # [1] <https://github.com/urllib3/urllib3/issues/651>
          release_this_conn = release_conn
  
          http_tunnel_required = connection_requires_http_tunnel(
              self.proxy, self.proxy_config, destination_scheme
          )
  
          # Merge the proxy headers. Only done when not using HTTP CONNECT. We
          # have to copy the headers dict so we can safely change it without those
          # changes being reflected in anyone else's copy.
          if not http_tunnel_required:
              headers = headers.copy()  # type: ignore[attr-defined]
              headers.update(self.proxy_headers)  # type: ignore[union-attr]
  
          # Must keep the exception bound to a separate variable or else Python 3
          # complains about UnboundLocalError.
          err = None
  
          # Keep track of whether we cleanly exited the except block. This
          # ensures we do proper cleanup in finally.
          clean_exit = False
  
          # Rewind body position, if needed. Record current position
          # for future rewinds in the event of a redirect/retry.
          body_pos = set_file_position(body, body_pos)
  
          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  # type: ignore[assignment]
  
              is_new_proxy_conn = self.proxy is not None and not getattr(
                  conn, "sock", None
              )
              if is_new_proxy_conn:
                  assert isinstance(self.proxy, Url)
                  conn._connecting_to_proxy = True
                  if http_tunnel_required:
                      try:
                          self._prepare_proxy(conn)
                      except (BaseSSLError, OSError, SocketTimeout) as e:
                          self._raise_timeout(
                              err=e, url=self.proxy.url, timeout_value=conn.timeout
                          )
                          raise
  
              # Make the request on the httplib connection object.
              httplib_response = self._make_request(
                  conn,
                  method,
                  url,
                  timeout=timeout_obj,
                  body=body,
                  headers=headers,
                  chunked=chunked,
              )
  
              # If we're going to release the connection in ``finally:``, then
              # the response 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 = conn if not release_conn else None
  
              # Pass method to Response for length checking
              response_kw["request_method"] = method
  
              # Import httplib's response into our own wrapper object
              response = self.ResponseCls.from_httplib(
                  httplib_response,
                  pool=self,
                  connection=response_conn,
                  retries=retries,
                  **response_kw,
              )
  
              # Everything went great!
              clean_exit = True
  
          except EmptyPoolError:
              # Didn't get a connection from the pool, no need to clean up
              clean_exit = True
              release_this_conn = False
              raise
  
          except (
              TimeoutError,
              HTTPException,
              OSError,
              ProtocolError,
              BaseSSLError,
              SSLError,
              CertificateError,
              ProxyError,
          ) as e:
              # Discard the connection for these exceptions. It will be
              # replaced during the next _get_conn() call.
              clean_exit = False
              new_e: Exception = e
              if isinstance(e, (BaseSSLError, CertificateError)):
                  new_e = SSLError(e)
              if isinstance(
                  new_e,
                  (
                      OSError,
                      NewConnectionError,
                      TimeoutError,
                      SSLError,
                      HTTPException,
                  ),
              ) and (conn and conn._connecting_to_proxy):
                  new_e = _wrap_proxy_error(new_e)
              elif isinstance(new_e, (OSError, HTTPException)):
                  new_e = ProtocolError("Connection aborted.", new_e)
  
              retries = retries.increment(
                  method, url, error=new_e, _pool=self, _stacktrace=sys.exc_info()[2]
              )
              retries.sleep()
  
              # Keep track of the error for the retry warning.
              err = e
  
          finally:
              if not clean_exit:
                  # We hit some kind of exception, handled or otherwise. We need
                  # to throw the connection away unless explicitly told not to.
                  # Close the connection, set the variable to None, and make sure
                  # we put the None back in the pool to avoid leaking it.
                  if conn:
                      conn.close()
                      conn = None
                  release_this_conn = True
  
              if release_this_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,
                  chunked=chunked,
                  body_pos=body_pos,
                  **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:
                      response.drain_conn()
                      raise
                  return response
  
              response.drain_conn()
              retries.sleep_for_retry(response)
              log.debug("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,
                  chunked=chunked,
                  body_pos=body_pos,
                  **response_kw,
              )
  
          # Check if we should retry the HTTP response.
          has_retry_after = bool(response.getheader("Retry-After"))
          if retries.is_retry(method, response.status, has_retry_after):
              try:
                  retries = retries.increment(method, url, response=response, _pool=self)
              except MaxRetryError:
                  if retries.raise_on_status:
                      response.drain_conn()
                      raise
                  return response
  
              response.drain_conn()
              retries.sleep(response)
              log.debug("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,
                  chunked=chunked,
                  body_pos=body_pos,
                  **response_kw,
              )
  
          return response
  
  
  class HTTPSConnectionPool(HTTPConnectionPool):
      """
      Same as :class:`.HTTPConnectionPool`, but HTTPS.
  
      :class:`.HTTPSConnection` 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``, ``ssl_version``, ``key_password`` 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: str,
          port: Optional[int] = None,
          timeout: Optional[_TYPE_TIMEOUT] = _DEFAULT_TIMEOUT,
          maxsize: int = 1,
          block: bool = False,
          headers: Optional[Mapping[str, str]] = None,
          retries: Optional[Union[Retry, bool, int]] = None,
          _proxy: Optional[Url] = None,
          _proxy_headers: Optional[Mapping[str, str]] = None,
          key_file: Optional[str] = None,
          cert_file: Optional[str] = None,
          cert_reqs: Optional[Union[int, str]] = None,
          key_password: Optional[str] = None,
          ca_certs: Optional[str] = None,
          ssl_version: Optional[Union[int, str]] = None,
          ssl_minimum_version: Optional["ssl.TLSVersion"] = None,
          ssl_maximum_version: Optional["ssl.TLSVersion"] = None,
          assert_hostname: Optional[Union[str, "Literal[False]"]] = None,
          assert_fingerprint: Optional[str] = None,
          ca_cert_dir: Optional[str] = None,
          **conn_kw: Any,
      ) -> None:
  
          super().__init__(
              host,
              port,
              timeout,
              maxsize,
              block,
              headers,
              retries,
              _proxy,
              _proxy_headers,
              **conn_kw,
          )
  
          self.key_file = key_file
          self.cert_file = cert_file
          self.cert_reqs = cert_reqs
          self.key_password = key_password
          self.ca_certs = ca_certs
          self.ca_cert_dir = ca_cert_dir
          self.ssl_version = ssl_version
          self.ssl_minimum_version = ssl_minimum_version
          self.ssl_maximum_version = ssl_maximum_version
          self.assert_hostname = assert_hostname
          self.assert_fingerprint = assert_fingerprint
  
      def _prepare_conn(self, conn: HTTPSConnection) -> HTTPConnection:
          """
          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,
                  key_password=self.key_password,
                  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
              conn.ssl_minimum_version = self.ssl_minimum_version
              conn.ssl_maximum_version = self.ssl_maximum_version
  
          return conn
  
      def _prepare_proxy(self, conn: HTTPSConnection) -> None:  # type: ignore[override]
          """
          Establishes a tunnel connection through HTTP CONNECT.
  
          Tunnel connection is established early because otherwise httplib would
          improperly set Host: header to proxy's IP:port.
          """
          conn.set_tunnel(self._proxy_host, self.port, self.proxy_headers)
  
          if self.proxy and self.proxy.scheme == "https":
              conn.tls_in_tls_required = True
  
          conn.connect()
  
      def _new_conn(self) -> HTTPConnection:
          """
          Return a fresh :class:`urllib3.connection.HTTPConnection`.
          """
          self.num_connections += 1
          log.debug(
              "Starting new HTTPS connection (%d): %s:%s",
              self.num_connections,
              self.host,
              self.port or "443",
          )
  
          if not self.ConnectionCls or self.ConnectionCls is DummyConnection:  # type: ignore[comparison-overlap]
              raise SSLError(
                  "Can't connect to HTTPS URL because the SSL module is not available."
              )
  
          actual_host: str = self.host
          actual_port = self.port
          if self.proxy is not None and self.proxy.host 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,
              cert_file=self.cert_file,
              key_file=self.key_file,
              key_password=self.key_password,
              **self.conn_kw,
          )
  
          return self._prepare_conn(conn)
  
      def _validate_conn(self, conn: HTTPConnection) -> None:
          """
          Called right before a request is made, after the socket is created.
          """
          super()._validate_conn(conn)
  
          # Force connect early to allow us to validate the connection.
          if not conn.sock:
              conn.connect()
  
          if not conn.is_verified:
              warnings.warn(
                  (
                      f"Unverified HTTPS request is being made to host '{conn.host}'. "
                      "Adding certificate verification is strongly advised. See: "
                      "https://urllib3.readthedocs.io/en/latest/advanced-usage.html"
                      "#tls-warnings"
                  ),
                  InsecureRequestWarning,
              )
  
  
  def connection_from_url(url: str, **kw: Any) -> HTTPConnectionPool:
      """
      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, *_ = parse_url(url)
      scheme = scheme or "http"
      port = port or port_by_scheme.get(scheme, 80)
      if scheme == "https":
          return HTTPSConnectionPool(host, port=port, **kw)  # type: ignore[arg-type]
      else:
          return HTTPConnectionPool(host, port=port, **kw)  # type: ignore[arg-type]
  
  
  @overload
  def _normalize_host(host: None, scheme: Optional[str]) -> None:
      ...
  
  
  @overload
  def _normalize_host(host: str, scheme: Optional[str]) -> str:
      ...
  
  
  def _normalize_host(host: Optional[str], scheme: Optional[str]) -> Optional[str]:
      """
      Normalize hosts for comparisons and use with sockets.
      """
  
      host = normalize_host(host, scheme)
  
      # httplib doesn't like it when we include brackets in IPv6 addresses
      # Specifically, if we include brackets but also pass the port then
      # httplib crazily doubles up the square brackets on the Host header.
      # Instead, we need to make sure we never pass ``None`` as the port.
      # However, for backward compatibility reasons we can't actually
      # *assert* that.  See http://bugs.python.org/issue28539
      if host and host.startswith("[") and host.endswith("]"):
          host = host[1:-1]
      return host
  