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Implementing the WSGI Streaming Service: (How to Detect Client Disconnect)

So what I'm doing is a WSGI streaming service record that uses an iterated wrapped queue to implement multicast push. The following is a simplified service model:

# this is managed by another thread
def processor_runner():
    generator = SerialMessageGenerator()
    for message in generator:
      for client in Processor.connections:
          client.put(message)

# this is managed by twisted wsgi implementation
def main(environ, start_response):
    queue = Queue()
    Processor.connections.append(queue)
    status = '200 OK'
    response_headers = [
        ('Content-Type', 'application/json'),
        ('Transfer-Encoding', 'chunked')
    ]
    start_response(status, response_headers)
    return iter(queue.get, None)

WSGI ( , - , ). : , , , ? , , .. (, ), , , put. , , . - - , - ?

, , , :

class IterableQueue(Queue):

def __init__(self):
    Queue.__init__(self) # Queue is an old style class
    ShellProcessor.connections.append(self)

def __iter__(self):
    return iter(self.get, None)

def close(self):
    self.put(None)
    self.task_done()
    ShellProcessor.connections.remove(self)
+5
2

.close() , , . - :

# ...
start_response(status, response_headers)
return ResponseIterator(iter(queue.get, None),
     on_finish=lambda: Processor.connections.remove(queue))

ResponseIterator :

class ResponseIterator:

  def __init__(self, iterator, on_finish=None):
      self.iterator = iterator
      self.on_finish = on_finish

  def __iter__(self):
      return self

  def next(self):
      return next(self.iterator)

  def close(self):
      if self.on_finish is not None:
         self.on_finish()
+1

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