Part of twisted.internet.abstract View Source View In Hierarchy
Known subclasses: twisted.internet.abstract.FileDescriptor, twisted.internet.iocpreactor.abstract.FileHandle
IConsumer
implementations can mix this in to get registerProducer and
unregisterProducer methods which take care of keeping track of
a producer's state.
Subclasses must provide three attributes which _ConsumerMixin
will read but not write:
bool which is True as long as
the the consumer has someplace to send bytes (for example, a TCP
connection), and then False when it no longer does.
bool which is False until
something like ITransport.loseConnection
is called, indicating that the send buffer should be flushed and the
connection lost afterwards. Afterwards, True.
bool which is False until the
consumer no longer has a place to send bytes, then True.
Subclasses must also override the startWriting method.
| Instance Variable | producer | None if no producer is registered, otherwise the registered
producer. |
| Instance Variable | producerPaused | A flag indicating whether the producer is currently paused. (type: bool) |
| Instance Variable | streamingProducer 0 | A flag indicating whether the producer was registered as a streaming (ie
push) producer or not (ie a pull producer). This will determine whether
the consumer may ever need to pause and resume it, or if it can merely call
resumeProducing on it when buffer space is available. |
| Instance Variable | streamingProducer | bool or int |
| Method | startWriting | No summary |
| Method | registerProducer | Register to receive data from a producer. |
| Method | unregisterProducer | Stop consuming data from a producer, without disconnecting. |
resumeProducing on it when buffer space is available.
unregisterProducer if loseConnection has
previously been called, so that the connection can actually close.This sets this selectable to be a consumer for a producer. When this selectable runs out of data on a write() call, it will ask the producer to resumeProducing(). When the FileDescriptor's internal data buffer is filled, it will ask the producer to pauseProducing(). If the connection is lost, FileDescriptor calls producer's stopProducing() method.
If streaming is true, the producer should provide the IPushProducer interface. Otherwise, it is assumed that producer provides the IPullProducer interface. In this case, the producer won't be asked to pauseProducing(), but it has to be careful to write() data only when its resumeProducing() method is called.