Re: SIMPLE chat: Status codes

Hi,

On Feb 8, 2012, at 9:10 AM, Miguel A. Garcia wrote:

> The SIMPLE chat draft, draft-ietf-simple-chat-13t.txt, went through the Apps review. The reviewer had a comment that requires a bit of discussion in the working group before we take an action. Here is the issue.
> 
> ---
> In Section 7.1:
> 
>     The reservation of a nickname can fail, e.g. if the NICKNAME request
>     contains a malformed or non-existent Use-Nickname header field, or
>     if the same nickname has already been reserved by another
>     participant (i.e., by another URI) in the chat room.  The
>     validation can also fail where the sender of the message is not
>     entitled to reserve the nickname.  In any of these cases the MSRP
>     switch MUST answer the NICKNAME request with a 423 response.  The
>     semantics of the 423 response are: "Nickname usage failed; the
>     nickname is not allocated to this user".
> 
> It would be better to use different response codes for different error
> conditions.
> ---
> 
> So, here is the discussion I would like to have. Do we need different response code for each of these issues? We can do:
> 

I agree, some more fine grained error reporting would help applications give better feedback.

> a) Do nothing and motivate why a single response code is sufficient
> 
> b) Create a response code for each error situation. This could be, e.g.:
> 
>   424 Malformed nickname
>   425 Nickname already in use
>   507 Not allowed to reserve a nickname
> 
> Notice that the "Not allowed to reserve nickname" should have a 500-class response to indicate a permanent failure, as opposed to the other two error codes, where a new request fixing the problem may succed.

These look just fine, user may just change the nickname and try again (in the 4xx cases), which I think it'll be helpful.

What about nickname policy? Lets say a focus doesn't allow "admin", "root" and "god" as nicknames, should we consider that a malformed nickname? It's not really malformed, it's explicitly forbidden. What about this?
  426 Forbidden nickname

> 
> Note: i just noticed that the 423 status code is already allocated (see http://www.iana.org/assignments/msrp-parameters/msrp-parameters.xml ) so I have chosen the next available status code.
> 
> 
> And while composing this e-mail, I revised the rest of the status codes that we are requesting, and we have requested a status code 428 for indicating "Private messages not supported". I think this should be a 500-class status code as well, since it is a permanent failure. Can we also move this one to 508?
> 

Agreed.


Regards,

-- 
Saúl Ibarra Corretgé
AG Projects