class twisted.internet.abstract._ConsumerMixin: (source)
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 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. |
| 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. |
None if no producer is registered, otherwise the registered producer.bool)
Override in a subclass to cause the reactor to monitor this selectable for write events. This will be called once in unregisterProducer if loseConnection has previously been called, so that the connection can actually close.
Register to receive data from a producer.
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.
Stop consuming data from a producer, without disconnecting.