[99s-extend] I need your feedback about this cowboy_rest handler.

[Loïc Hoguin]

Hey,

On 08/27/2014 12:29 PM, Stéphane Wirtel wrote:
> Hi all,
>
> This night, I wrote an example because I wanted to show you my work.
>
> I have one handler for the concept of collections (in this case, tasks).
>
> In this handler, I want these following methods:
>
> POST /:collection
> GET /:collection
> DELETE /:collection
> PUT /:collection
> HEAD /:collection
>
> :collection is a string, example: /tasks1
>
> HEAD /:collection (/tasks1)
> StatusCode:
>      * 200 ok
>      * 404 not found
>
> GET /:collection (/tasks1)
> Gets information about the collection
> StatusCode:
>      * 200 ok
>      * 404 not found
>
> PUT /:collection (/tasks1)
> Create a new collection of tasks
> Status_Code:
>      * 201 created
>      Response: an object, in msgpack or json and I need to had a
> location header
>      * 412 precondition failed, the collection name already exists
>      Response: an object, in msgpack or json with the error (already
> exists)
>
> POST /:collection (/tasks1)
> Add a new item in the collection, a new task
> StatusCode:
>      * 201 created
>      * 202 accepted
>      * 404 not found (error in the collection name)
> Response: need to add a location header and return an object in msgpack
> or json.
>
> DELETE /:collection (/tasks1)
> Delete all the tasks
> Status_Code:
>      * 200 ok.
>      * 404 not found
> In the case of 200, we need to return an object in msgpack or json.
>
>
> I provided a code and If you can help me, because I think cowboy_rest is
> a good solution, but I also think I will have some problems with my
> service.
>
> Examples:
> * delete_completed, I need to write the serialisation in the
> delete_completed function and not with the help of the defined callbacks
> of content_types_provided.

What's the problem? The callbacks you set in content_types_provided are 
there to provide the *resource*. If you set a body in response to the 
DELETE method you are not sending the resource but information about the 
result of the operation.

> * for PUT, I need to return a location header, should I add it in the
> is_conflict
> function?

I would say in the callback you set in content_types_accepted. But...

> * for PUT, how I have a 201? I have read the rest_flowchart and I need
> to specify the location header ok, but where? in the is_conflict function?

Why do you need a 201? If you PUT a collection to /:collection then this 
is already the location of the collection. I am not sure what you are 
trying to do there exactly?

> So, do you have time to help me, because with this example, I can
> propose it to the cowboy repository.
> https://github.com/matrixise/demo_rest/blob/master/src/collection_handler.erl
>
>
> You can propose your PR, comments or remarks, but I would like to use
> cowboy_rest.
>
> Regards,
>
> Stephane
>
> --
> Stéphane Wirtel - http://wirtel.be - @matrixise
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-- 
Loïc Hoguin
http://ninenines.eu