As Aristotle replied, Location header is unspecified for 202
(Accepted). Instead, provide a body such as the following:

<status>
<link href="http://example.org/stats?someid"/>
...
</status>

so that the client can check the status of the response. If the
process succeeded in creating a resource, only then provide a link to
the newly created resource, which you can do as part of the status
check response. That is, don't advertise /backups/version_x until the
resource has been created. Here is a possible flow:

POST /something ===> 202 Accepted + link to a status check URL with in
the response
GET /status_check_url => 200 OK + status response, when not completed
GET /status_check_url => 200 OK + status response, when completed, but
was not successful
GET /status_check_url => 300 See Other + Location: uri_to_resource,
when competed successfully

Subbu

On Sep 6, 2008, at 1:21 PM, bierstuebl wrote:

> Hi all,
>
> I'm new to this mailing list and to be honest: I've neve been on a
> mailing list before. So in case I'm doing things wrong, please be
> forgiving.
>
> However, here is my first question:
>
> I would like to use asynchronous REST by POSTing a request to e.g.
> /backups (for creating a new backup version), which will return me a
> 202 with a location in the header. What should this location look
> like?
> I think it should look like /backups/version_x and NOT be somewhere
> else like /queue/backups/version_x or the like.
> However, if a client starts polling now on /backups/version_x and the
> process hasn't finished yet, what should be returned? A 404 with a
> body until the process is finished an the real representation can be
> sent with 200?
>
> Using a new resource like /queue/backups/version I could return a 200
> with some status information in it. However, the client initially
> requested a representation of a backup, but when it starts polling on
> the new resource it receives another representation, the a status
> representeation. How could a client adjust to this situation without
> knowing in advance that the action would be asynchronous??
>
> Hmm, it's difficult to describe the problem. I hope it's
> understandable somehow.
>
> regards,
> Roland
>
>
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