HTTPAdapter Class — requests Architecture

Source Code

src/requests/adapters.py lines 145–698

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().__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 {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>`.