twisted.internet.abstract._ConsumerMixin(object)
class documentationtwisted.internet.abstract
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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. (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.
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.