twisted.web._http2.H2Connection

Implements interfaces: twisted.internet.interfaces.IProtocol, twisted.internet.interfaces.IPushProducer

A class representing a single HTTP/2 connection.

This implementation of IProtocol works hand in hand with H2Stream. This is because we have the requirement to register multiple producers for a single HTTP/2 connection, one for each stream. The standard Twisted interfaces don't really allow for this, so instead there's a custom interface between the two objects that allows them to work hand-in-hand here.

Instance Variable	conn	The HTTP/2 connection state machine. (type: `h2.connection.H2Connection`)
Instance Variable	streams	A mapping of stream IDs to `H2Stream` objects, used to call specific methods on streams when events occur. (type: `dict`, mapping `int` stream IDs to `H2Stream` objects.)
Instance Variable	priority	A HTTP/2 priority tree used to ensure that responses are prioritised appropriately. (type: `priority.PriorityTree`)
Instance Variable	abortTimeout	The number of seconds to wait after we attempt to shut the transport down cleanly to give up and forcibly terminate it. This is only used when we time a connection out, to prevent errors causing the FD to get leaked. If this is `None`, we will wait forever. (type: `int`)
Method	__init__	Undocumented
Method	connectionMade	Called by the reactor when a connection is received. May also be called by the `twisted.web.http._GenericHTTPChannelProtocol` during upgrade to HTTP/2.
Method	dataReceived	Called whenever a chunk of data is received from the transport.
Method	timeoutConnection	No summary
Method	forceAbortClient	No summary
Method	connectionLost	Called when the transport connection is lost.
Method	stopProducing	Stop producing data.
Method	pauseProducing	Pause producing data.
Method	resumeProducing	Resume producing data.
Method	writeHeaders	Called by `twisted.web.http.Request` objects to write a complete set of HTTP headers to a stream.
Method	writeDataToStream	May be called by `H2Stream` objects to write response data to a given stream. Writes a single data frame.
Method	endRequest	Called by `H2Stream` objects to signal completion of a response.
Method	abortRequest	Called by `H2Stream` objects to request early termination of a stream. This emits a RstStream frame and then removes all stream state.
Method	remainingOutboundWindow	Called to determine how much room is left in the send window for a given stream. Allows us to handle blocking and unblocking producers.
Method	getPeer	Get the remote address of this connection.
Method	getHost	Similar to getPeer, but returns an address describing this side of the connection.
Method	openStreamWindow	Open the stream window by a given increment.
Instance Variable	_consumerBlocked	A flag tracking whether or not the `IConsumer` that is consuming this data has asked us to stop producing. (type: A `twisted.internet.defer.Deferred`, or `None`)
Instance Variable	_sendingDeferred	A `Deferred` used to restart the data-sending loop when more response data has been produced. Will not be present if there is outstanding data still to send.
Instance Variable	_outboundStreamQueues	A map of stream IDs to queues, used to store data blocks that are yet to be sent on the connection. These are used both to handle producers that do not respect `IConsumer` but also to allow priority to multiplex data appropriately. (type: A `dict` mapping `int` stream IDs to `collections.deque` queues, which contain either `bytes` objects or `_END_STREAM_SENTINEL`.)
Instance Variable	_sender	A handle to the data-sending loop, allowing it to be terminated if needed. (type: `twisted.internet.task.LoopingCall`)
Instance Variable	_abortingCall	The `twisted.internet.base.DelayedCall` that will be used to forcibly close the transport if it doesn't close cleanly. (type: `twisted.internet.base.DelayedCall`)
Method	_sendPrioritisedData	The data sending loop. This function repeatedly calls itself, either from `Deferred`s or from `reactor.callLater`
Method	_requestReceived	Internal handler for when a request has been received.
Method	_requestDataReceived	Internal handler for when a chunk of data is received for a given request.
Method	_requestEnded	Internal handler for when a request is complete, and we expect no further data for that request.
Method	_requestAborted	Internal handler for when a request is aborted by a remote peer.
Method	_handlePriorityUpdate	Internal handler for when a stream priority is updated.
Method	_requestDone	Called internally by the data sending loop to clean up state that was being used for the stream. Called when the stream is complete.
Method	_handleWindowUpdate	Manage flow control windows.
Method	_isSecure	Returns `True` if this channel is using a secure transport.
Method	_send100Continue	Sends a 100 Continue response, used to signal to clients that further processing will be performed.
Method	_respondToBadRequestAndDisconnect	This is a quick and dirty way of responding to bad requests.
Method	_streamIsActive	Checks whether Twisted has still got state for a given stream and so can process events for that stream.
Method	_tryToWriteControlData	Checks whether the connection is blocked on flow control and, if it isn't, writes any buffered control data.
Method	_flushBufferedControlData	Called when the connection is marked writable again after being marked unwritable. Attempts to flush buffered control data if there is any.

Inherited from Protocol:

Method

logPrefix

Return a prefix matching the class name, to identify log messages related to this protocol instance.

Inherited from BaseProtocol (via Protocol):

Method

makeConnection

Make a connection to a transport and a server.

Inherited from TimeoutMixin:

Class Variable	timeOut	The number of seconds after which to timeout the connection.
Method	callLater	Wrapper around `reactor.callLater` for test purpose.
Method	resetTimeout	Reset the timeout count down.
Method	setTimeout	Change the timeout period
Method	__timedOut	Undocumented

conn =

The HTTP/2 connection state machine. (type: h2.connection.H2Connection)

streams =

A mapping of stream IDs to H2Stream objects, used to call specific methods on streams when events occur. (type: dict, mapping int stream IDs to H2Stream objects.)

priority =

A HTTP/2 priority tree used to ensure that responses are prioritised appropriately. (type: priority.PriorityTree)

_consumerBlocked =

A flag tracking whether or not the IConsumer that is consuming this data has asked us to stop producing. (type: A twisted.internet.defer.Deferred, or None)

_sendingDeferred =

A Deferred used to restart the data-sending loop when more response data has been produced. Will not be present if there is outstanding data still to send.

_outboundStreamQueues =

A map of stream IDs to queues, used to store data blocks that are yet to be sent on the connection. These are used both to handle producers that do not respect IConsumer but also to allow priority to multiplex data appropriately. (type: A dict mapping int stream IDs to collections.deque queues, which contain either bytes objects or _END_STREAM_SENTINEL.)

_sender =

A handle to the data-sending loop, allowing it to be terminated if needed. (type: twisted.internet.task.LoopingCall)

abortTimeout =

The number of seconds to wait after we attempt to shut the transport down cleanly to give up and forcibly terminate it. This is only used when we time a connection out, to prevent errors causing the FD to get leaked. If this is None, we will wait forever. (type: int)

_abortingCall =

The twisted.internet.base.DelayedCall that will be used to forcibly close the transport if it doesn't close cleanly. (type: twisted.internet.base.DelayedCall)

def __init__(self, reactor=None):

Undocumented

def connectionMade(self):

from twisted.internet.interfaces.IProtocol

overrides twisted.internet.protocol.BaseProtocol.connectionMade

Called by the reactor when a connection is received. May also be called by the twisted.web.http._GenericHTTPChannelProtocol during upgrade to HTTP/2.

def dataReceived(self, data):

from twisted.internet.interfaces.IProtocol

overrides twisted.internet.protocol.Protocol.dataReceived

Called whenever a chunk of data is received from the transport.

Parameters data The data received from the transport. (type: bytes)

def timeoutConnection(self):

overrides twisted.protocols.policies.TimeoutMixin.timeoutConnection

Called when the connection has been inactive for self.timeOut seconds. Cleanly tears the connection down, attempting to notify the peer if needed.

We override this method to add two extra bits of functionality:

We want to log the timeout.
We want to send a GOAWAY frame indicating that the connection is being terminated, and whether it was clean or not. We have to do this before the connection is torn down.

def forceAbortClient(self):

Called if abortTimeout seconds have passed since the timeout fired, and the connection still hasn't gone away. This can really only happen on extremely bad connections or when clients are maliciously attempting to keep connections open.

def connectionLost(self, reason, _cancelTimeouts=True):

from twisted.internet.interfaces.IProtocol

overrides twisted.internet.protocol.Protocol.connectionLost

Called when the transport connection is lost.

Informs all outstanding response handlers that the connection has been lost, and cleans up all internal state.

Parameters	reason	See `IProtocol.connectionLost`
	_cancelTimeouts	Propagate the `reason` to this connection's streams but don't cancel any timers, so that peers who never read the data we've written are eventually timed out.

def stopProducing(self):

from twisted.internet.interfaces.IProducer

Stop producing data.

This tells the H2Connection that its consumer has died, so it must stop producing data for good.

def pauseProducing(self):

from twisted.internet.interfaces.IPushProducer

Pause producing data.

Tells the H2Connection that it has produced too much data to process for the time being, and to stop until resumeProducing() is called.

def resumeProducing(self):

from twisted.internet.interfaces.IPushProducer

Resume producing data.

This tells the H2Connection to re-add itself to the main loop and produce more data for the consumer.

def _sendPrioritisedData(self, *args):

The data sending loop. This function repeatedly calls itself, either from Deferreds or from reactor.callLater

This function sends data on streams according to the rules of HTTP/2 priority. It ensures that the data from each stream is interleved according to the priority signalled by the client, making sure that the connection is used with maximal efficiency.

This function will execute if data is available: if all data is exhausted, the function will place a deferred onto the H2Connection object and wait until it is called to resume executing.

def _requestReceived(self, event):

Internal handler for when a request has been received.

Parameters event The Hyper-h2 event that encodes information about the received request. (type: h2.events.RequestReceived)

def _requestDataReceived(self, event):

Internal handler for when a chunk of data is received for a given request.

Parameters event The Hyper-h2 event that encodes information about the received data. (type: h2.events.DataReceived)

def _requestEnded(self, event):

Internal handler for when a request is complete, and we expect no further data for that request.

Parameters event The Hyper-h2 event that encodes information about the completed stream. (type: h2.events.StreamEnded)

def _requestAborted(self, event):

Internal handler for when a request is aborted by a remote peer.

Parameters event The Hyper-h2 event that encodes information about the reset stream. (type: h2.events.StreamReset)

def _handlePriorityUpdate(self, event):

Internal handler for when a stream priority is updated.

Parameters event The Hyper-h2 event that encodes information about the stream reprioritization. (type: h2.events.PriorityUpdated)

def writeHeaders(self, version, code, reason, headers, streamID):

Called by twisted.web.http.Request objects to write a complete set of HTTP headers to a stream.

Parameters	version	The HTTP version in use. Unused in HTTP/2. (type: `bytes`)
	code	The HTTP status code to write. (type: `bytes`)
	reason	The HTTP reason phrase to write. Unused in HTTP/2. (type: `bytes`)
	headers	The headers to write to the stream. (type: `twisted.web.http_headers.Headers`)
	streamID	The ID of the stream to write the headers to. (type: `int`)

def writeDataToStream(self, streamID, data):

May be called by H2Stream objects to write response data to a given stream. Writes a single data frame.

Parameters	streamID	The ID of the stream to write the data to. (type: `int`)
	data	The data chunk to write to the stream. (type: `bytes`)

def endRequest(self, streamID):

Called by H2Stream objects to signal completion of a response.

Parameters streamID The ID of the stream to write the data to. (type: int)

def abortRequest(self, streamID):

Called by H2Stream objects to request early termination of a stream. This emits a RstStream frame and then removes all stream state.

Parameters streamID The ID of the stream to write the data to. (type: int)

def _requestDone(self, streamID):

Called internally by the data sending loop to clean up state that was being used for the stream. Called when the stream is complete.

Parameters streamID The ID of the stream to clean up state for. (type: int)

def remainingOutboundWindow(self, streamID):

Called to determine how much room is left in the send window for a given stream. Allows us to handle blocking and unblocking producers.

Parameters	streamID	The ID of the stream whose flow control window we'll check. (type: `int`)
Returns	The amount of room remaining in the send window for the given stream, including the data queued to be sent. (type: `int`)

def _handleWindowUpdate(self, event):

Manage flow control windows.

Streams that are blocked on flow control will register themselves with the connection. This will fire deferreds that wake those streams up and allow them to continue processing.

Parameters event The Hyper-h2 event that encodes information about the flow control window change. (type: h2.events.WindowUpdated)

def getPeer(self):

Get the remote address of this connection.

Treat this method with caution. It is the unfortunate result of the CGI and Jabber standards, but should not be considered reliable for the usual host of reasons; port forwarding, proxying, firewalls, IP masquerading, etc.

Returns An IAddress provider.

def getHost(self):

Similar to getPeer, but returns an address describing this side of the connection.

Returns An IAddress provider.

def openStreamWindow(self, streamID, increment):

Open the stream window by a given increment.

Parameters	streamID	The ID of the stream whose window needs to be opened. (type: `int`)
	increment	The amount by which the stream window must be incremented. (type: `int`)

def _isSecure(self):

Returns True if this channel is using a secure transport.

Returns True if this channel is secure. (type: bool)

def _send100Continue(self, streamID):

Sends a 100 Continue response, used to signal to clients that further processing will be performed.

Parameters streamID The ID of the stream that needs the 100 Continue response (type: int)

def _respondToBadRequestAndDisconnect(self, streamID):

This is a quick and dirty way of responding to bad requests.

As described by HTTP standard we should be patient and accept the whole request from the client before sending a polite bad request response, even in the case when clients send tons of data.

Unlike in the HTTP/1.1 case, this does not actually disconnect the underlying transport: there's no need. This instead just sends a 400 response and terminates the stream.

Parameters streamID The ID of the stream that needs the 100 Continue response (type: int)

def _streamIsActive(self, streamID):

Checks whether Twisted has still got state for a given stream and so can process events for that stream.

Parameters	streamID	The ID of the stream that needs processing. (type: `int`)
Returns	Whether the stream still has state allocated. (type: `bool`)

def _tryToWriteControlData(self):

Checks whether the connection is blocked on flow control and, if it isn't, writes any buffered control data.

Returns True if the connection is still active and False if it was aborted because too many bytes have been written but not consumed by the other end.

def _flushBufferedControlData(self, *args):

Called when the connection is marked writable again after being marked unwritable. Attempts to flush buffered control data if there is any.

API Documentation for twisted, generated by pydoctor at 2020-03-25 17:34:30.

twisted.web._http2.H2Connection(Protocol, TimeoutMixin) class documentation

`twisted.web._http2.H2Connection(Protocol, TimeoutMixin)` class documentation