twisted.web.client.HTTPConnectionPool

class documentation

class HTTPConnectionPool: (source)

Constructor: HTTPConnectionPool(reactor, persistent)

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A pool of persistent HTTP connections.

Features:

  • Cached connections will eventually time out.
  • Limits on maximum number of persistent connections.

Connections are stored using keys, which should be chosen such that any connections stored under a given key can be used interchangeably.

Failed requests done using previously cached connections will be retried once if they use an idempotent method (e.g. GET), in case the HTTP server timed them out.

Present Since
12.1
Method __init__ Undocumented
Method closeCachedConnections Close all persistent connections and remove them from the pool.
Method getConnection Supply a connection, newly created or retrieved from the pool, to be used for one HTTP request.
Instance Variable cachedConnectionTimeout Number of seconds a cached persistent connection will stay open before disconnecting.
Instance Variable maxPersistentPerHost The maximum number of cached persistent connections for a host:port destination.
Instance Variable persistent Boolean indicating whether connections should be persistent. Connections are persistent by default.
Instance Variable retryAutomatically boolean indicating whether idempotent requests should be retried once if no response was received.
Method _newConnection Create a new connection.
Method _putConnection Return a persistent connection to the pool. This will be called by HTTP11ClientProtocol when the connection becomes quiescent.
Method _removeConnection Remove a connection from the cache and disconnect it.
Class Variable _log Undocumented
Instance Variable _connections Map (scheme, host, port) to lists of HTTP11ClientProtocol instances.
Instance Variable _factory The factory used to connect to the proxy.
Instance Variable _reactor Undocumented
Instance Variable _timeouts Map HTTP11ClientProtocol instances to a IDelayedCall instance of their timeout.
def __init__(self, reactor, persistent=True): (source)

Undocumented

def closeCachedConnections(self): (source)

Close all persistent connections and remove them from the pool.

Returns
defer.Deferred that fires when all connections have been closed.
def getConnection(self, key, endpoint): (source)

Supply a connection, newly created or retrieved from the pool, to be used for one HTTP request.

The connection will remain out of the pool (not available to be returned from future calls to this method) until one HTTP request has been completed over it.

Afterwards, if the connection is still open, it will automatically be added to the pool.

Parameters
keyA unique key identifying connections that can be used interchangeably.
endpointAn endpoint that can be used to open a new connection if no cached connection is available.
Returns
A Deferred that will fire with a HTTP11ClientProtocol (or a wrapper) that can be used to send a single HTTP request.
cachedConnectionTimeout: int = (source)

Number of seconds a cached persistent connection will stay open before disconnecting.

maxPersistentPerHost: int = (source)

The maximum number of cached persistent connections for a host:port destination.

persistent = (source)

Boolean indicating whether connections should be persistent. Connections are persistent by default.

retryAutomatically: bool = (source)

boolean indicating whether idempotent requests should be retried once if no response was received.

def _newConnection(self, key, endpoint): (source)

Create a new connection.

This implements the new connection code path for getConnection.

def _putConnection(self, key, connection): (source)

Return a persistent connection to the pool. This will be called by HTTP11ClientProtocol when the connection becomes quiescent.

def _removeConnection(self, key, connection): (source)

Remove a connection from the cache and disconnect it.

_log = (source)

Undocumented

_connections: dict = (source)

Map (scheme, host, port) to lists of HTTP11ClientProtocol instances.

_factory = (source)

The factory used to connect to the proxy.

_reactor = (source)

Undocumented

_timeouts: dict = (source)

Map HTTP11ClientProtocol instances to a IDelayedCall instance of their timeout.