[ckan-discuss] CKAN API and relationships

Mon Jan 23 17:10:29 GMT 2012

On 23 January 2012 16:11, Richard Cyganiak <richard at cyganiak.de> wrote:
> Hi David,
>
> On 23 Jan 2012, at 12:54, David Read wrote:
>>> We need another type: links_to.
>>
>> Yes, these are designed to be added when good use cases come along
>> like this, so I will add it. There's an argument for making it
>> arbitrary, but I think we'll keep it constrained whilst we see how it
>> gets used.
>
> FWIW, we brainstormed possible other relationship types during November's CKAN+LD meetup, and I think all other types that came up do fit more or less comfortably into the existing set.
>
>> I'll see if we can easily add a 'count' property for this one, to
>> store the number of links,
>
> That would be really great.
>
>> I've put these requests in a ticket http://trac.ckan.org/ticket/1695
>> and since it should be quick, I'll aim to get these onto the datahub
>> in the next couple of weeks.
>
> That's great news! Looking forward!
>
>> By the way, you may wish to play with these using the version 3 of the
>> API - we'd be interested in your views. It's RPC style rather than
>> RESTful. The v1 and v2 APIs remain as RESTful wrappers over calls such
>> as 'package_relationship_create'. There are still rough edges, such as
>> 500 error if you get don't send the right parameters, but otherwise
>> we're pleased about the extra feedback it gives. Docs:
>> http://readthedocs.org/docs/ckan/en/latest/apiv3.html
>
> Yeah I've seen the v3 API docs. And to be honest I'm not a big fan.
>
> It's a bit hard for me to articulate why. From my point of view – someone who started knowing nothing about the API, doesn't have much time, and wants to learn just enough to get a particular small job done – the v2 version just seems more approachable.
>
> Figuring out how to read from v2 is really trivial. All I need is this little table here, and a web browser to test some calls:
> http://readthedocs.org/docs/ckan/en/latest/api.html#model-resources
>
> In the v3 version, I can't do anything in the browser; I need to start messing around with curl to do even the most simple interaction. To be honest, when I saw that I need POST to read from v3, I cursed a little and went right back to v2… The exposed function calls in v3 also seem more low-level. v2 feels like it's on a higher level of abstraction.
>
> (If CKAN had *only* the v3 API, then I'd maybe grumble a bit about not being able to read with GET, and get on with it. But with both the REST-style v2 and the RPC-style v3 available, there is very little that draws me to v3…)
>
> I apologize for this rather unproductive and negative message :-/

Not at all, it's all useful feedback. This encourages us to maintain
the RESTful interfaces, certainly for basic data operations that suit
it. I suspect the javascript developers out there are much happier
with the RPC-style interface for doing autocomplete and other whizzy
form things. And the people writing custom interfaces in Drupal etc.
will appreciate the richer RPC calls than REST would ever give us. So
I hope we are cater for broad needs.

Dave

>
> Richard