[Twisted-Python] [twisted.mail][newbie] return tempfail (4xx) after eomReceived()

[Fabio Sangiovanni]

Hi,

thanks for your anwser, and forgive my late follow up.
So, I understand that this feature is currently missing in twisted. I 
suppose that the only thing to do in my case is to override the 
_messageHandled method, and implement all the logic needed to my 
purpose. Is this correct? Are you aware of some technique other people 
adopted?

Thanks a lot,
Fabio

On 23/11/13 13:08, exarkun at twistedmatrix.com wrote:
> On 10:36 am, sangiovanni at nweb.it wrote:
>> Hello list,
>>
>> I'm trying to code an SMTP server that stores received messages in a 
>> queue (es. RabbitMQ or Redis).
>> I'm figuring out how to do it with Twisted, and so far I managed to 
>> print to console the messages the way I want.
>> I'm trying to understand now how to return a tempfail code (4xx) from 
>> within eomReceived(), so to simulate (and, in the future, handle) 
>> temporary unavailabilities of the queuing system, and thus to 
>> delegate to the client the handling/retrying of the delivery (there 
>> will be postfix in front of my smtp server, so it will keep the 
>> message in its spool).
>> I ended up digging in the code until I found the _messageHandled 
>> callback of the SMTP class, that's added to the deferred returned by 
>> eomReceived. I admit I'm not very accustomed to deferreds yet, but I 
>> can only see 250 and 550 response code inside it. I suspect that I 
>> should return the 4xx code in one of the deferred's 
>> callbacks/errbacks *before* _messageHandled, but I really can't 
>> imagine how. Would you please give me some hints about how to 
>> accomplish the task? Am I looking to the right direction at all?
>
> See https://twistedmatrix.com/trac/ticket/4904
>
> Jean-Paul
>
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