[Twisted-Python] Using SerialPort with t.a.s.Application

[Albert Brandl]

Hi!

I'm quite happy that my question (or really: Itamar's answer) triggered 
the interesting discussion about glossaries. But there are some aspects 
about SerialPort that are not yet clear to me. So I'm trying to reclaim 
this thread ;-).

On Fri, Jan 28, 2011 at 08:25:52AM -0500, Itamar Turner-Trauring wrote:
> The TCP port doesn't implement IService either...

This is correct. But TCPServer does implement IService, and I was 
looking for an analog I could use for the serial port. I'd like to write 
something along the following lines:

def setupSerialCommunication(multiService):
    lrFactory = MyLineReceiverFactory()
    serialComm = internet.SerialServer(lrFactory, '/dev/ttyS0')
    serialComm.setServiceParent(multiService)

(BTW: I'm not quite sure if SerialServer would belong to the internet
package...)

In my understanding, the communication over the serial line should be 
handled in a similar way to communicating via TCP/IP. So my questions
should have been: Why isn't there an analog to TCPServer for SerialPort?
Would it make sense to add it?

> A service is supposed to be something you can start and stop, and 
> encapsulates a self-contained piece of business logic. The purpose is 
> both deployment and ease of regression testing.

Thanks for the explanation. It is certainly a good idea to think about
the partitioning of the services and reflect it in the code.

> So maybe your service starts both a webserver and a serialport, 
> because it requires both -- which is why mostly you should just 
> implement your own service classes.

There is the class t.a.s.MultiService for encapsulating other services. 
In my current implementation I just instantiate it and add the other 
services; afterwards I set its service Parent to the application. What 
would be the advantage of subclassing Service and redefining its 
startService and stopService methods?

Thanks & best regards,

Albert
-- 
Albert Brandl
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