Python server: how to receive data for X seconds?

Question

For testing porpoises, my Python server has to receive data for X seconds.

def ReceiveUplinkData(connection, uplinkTimer):
    try:
        global uplinkDataBlockSize

        print 'Server is receiving uplink data for ' + str(uplinkTimer) + ' seconds'

        bytesRecieved = 0
        start_time = time.time()

        while True:
            data = connection.recv(uplinkDataBlockSize)
            #print 'Server received "%s"' % data
            if data:
                bytesRecieved += len(data)

            if time.time() - start_time >= uplinkTimer:
                break

    # +=+=+=+=+=+=+=+=+=+=+=+=+=
    except KeyboardInterrupt, e:  # Ctrl-C
        raise e
    except SystemExit, e:  # sys.exit()
        raise e
    except Exception, e:
        print 'Error, undetected exception'
        print str(e)
        traceback.print_exc()
        os._exit(1)

    # +=+=+=+=+=+=+=+=+=+=+=+=+=
    finally:
            end_time = time.time()
            print 'End of uplink data transfer. ' + str(bytesRecieved) + 
                  ' bytes received in ' + str(end_time - start_time) + ' seconds'

If I make the connection blocking, then it hangs if the client transmits for less than X seconds.

I make it non-blocking ( connection.setblocking(0) ), then I hit an exception

Error, undetected exception
[Errno 10035] A non-blocking socket operation could not be completed immediately
Traceback (most recent call last):
  File "c:\server.py", line 28, in ReceiveUplinkData
    data = connection.recv(uplinkDataBlockSize)
error: [Errno 10035] A non-blocking socket operation could not be completed immediately

Can someone either tell me how to fix my code, or point me at simple example which I can copy?

Answer 1

Change your while condition to track how much time has elapsed

while time.time() - start_time >= uplinkTimer:
    data = connection.recv(uplinkDataBlockSize)
    #print 'Server received "%s"' % data
    if data:
        bytesRecieved += len(data)

The reason you are getting an exceptionad could be because there is no more data to receive. Per the docs, when you set the socket to non-blocking mode, if a recv() call doesn't find any data, or if a send() call can't immediately dispose of the data, an error exception is raised.