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Out of all the proposals mentioned in this thread, I think Jay's (d) option
is what is closer to the REST ideal:

d) POST /images/{image_id}/tasks with payload:
   { "action": "deactivate|activate" }

Even though I don't think this is the perfect solution, I can recognize
that at least it tries to be RESTful, unlike the other three options
suggested in the first message.

That said, I'm going to keep insisting that in a REST API state changes are
the most important thing, and actions are implicitly derived by the server
from these state changes requested by the client. What you are trying to do
is to reverse this flow, you want the client to invoke an action, which in
turn will cause an implicit state change on the server. This isn't wrong in
itself, it's just not the way you do REST.

Jay's (d) proposal above could be improved by making the task a real
resource. Sending a POST request to the /tasks address creates a new task
resource, which gets a URI of its own, returned in the Location header. You
can then send a GET request to this URI to obtain status info, such as
whether the task completed or not. And since tasks are now real resources,
they should have a documented representation as well.

Miguel

On Wed, Feb 18, 2015 at 1:19 PM, Brian Rosmaita <
brian.rosmaita at rackspace.com> wrote:

> On 2/15/15, 2:35 PM, "Jay Pipes" <jaypipes at gmail.com> wrote:
> >On 02/15/2015 01:13 PM, Brian Rosmaita wrote:
> >> On 2/15/15, 10:10 AM, "Jay Pipes" <jaypipes at gmail.com> wrote:
> >>
> >>> On 02/15/2015 01:31 AM, Brian Rosmaita wrote:
> >>>> This is a follow-up to the discussion at the 12 February API-WG
> >>>> meeting [1] concerning "functional" API in Glance [2].  We made
> >>>> some progress, but need to close this off so the spec can be
> >>>> implemented in Kilo.
> >>>>
> >>>> I believe this is where we left off: 1. The general consensus was
> >>>> that POST is the correct verb.
> >>>
> >>> Yes, POST is correct (though the resource is wrong).
> >>>
> >>>> 2. Did not agree on what to POST.  Three options are in play: (A)
> >>>> POST /images/{image_id}?action=deactivate POST
> >>>> /images/{image_id}?action=reactivate
> >>>>
> >>>> (B) POST /images/{image_id}/actions with payload describing the
> >>>> action, e.g., { "action": "deactivate" } { "action": "reactivate"
> >>>> }
> >>>>
> >>>> (C) POST /images/{image_id}/actions/deactivate POST
> >>>> /images/{image_id}/actions/reactivate
> >>>
> >>> d) POST /images/{image_id}/tasks with payload: { "action":
> >>> "deactivate|activate" }
> >>>
> >>> An action isn't created. An action is taken. A task is created. A
> >>> task contains instructions on what action to take.
> >>
> >> The Images API v2 already has tasks (schema available at
> >> /v2/schemas/tasks ), which are used for long-running asynchronous
> >> operations (right now, image import and image export).  I think we
> >> want to keep those distinct from what we're talking about here.
> >>
> >> Does something really need to be created for this call?  The idea
> >> behind the "functional" API was to have a place for things that don't
> >> fit neatly into the CRUD-centric paradigm.  Option (C) seems like a
> >> good fit for this.
> >
> >Why not just use the existing tasks/ interface, then? :) Seems like a
> >perfect fit to me.
>
> The existing tasks/ interface is kind of heavyweight.  It provides a
> framework for asynchronous operations.  It's really not appropriate for
> this purpose.
>
> cheers,
> brian
>
>
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