Re: ISSUE-31: Are Operations violating REST's uniform interface constraint?

On 2/6/14 7:02 PM, Ryan J. McDonough wrote:
> On Feb 6, 2014, at 12:29 PM, Markus Lanthaler <markus.lanthaler@gmx.net> wrote:
>
>>> On Wed, Feb 5, 2014 at 2:06 PM, Markus Lanthaler wrote:
>>>> Great. So, before I close this issue I would like to get Mark's
>>>> opinion (that's why I CCed you). Mark, do you agree with Ryan on
>>>> this or do you think Operations do violate REST's uniform
>>>> interface constraint?
>>> I believe they violate the constraint, yes.
>> Let me ask a provocative question: Why do you think Operations violate the
>> constraint whereas link relations, which further describe a potential GET
>> request, don’t?
>
> I’m very interested in this as well. But I think the GET request may be too trivial. Give the following Link header:
>
> Link: <http://example.com/search>; rel="search"; title="Simple Search”
>
> We could express this in Hyrda with something like:
>
> “@id” : "http://example.com/search”,
> “@type” : “search”
>
> I don’t think that’s where Mark is concerned. Please correct me if I am mistaken Mark)
>
> I believe the area of concern  arises in the more detailed operations that send message. But since I’m missing it too, I thought I’d take a moment and create a search use case and express it in HTML, Open Search, and Hyrda.
>
> In HTML we have:
>
> <form id="search" action="http://example.com/search" method="POST">
> 	<input type="text" id="q"/>
> 	<input type="text" id="count"/>
> 	<input type="text" id="start"/>
> </form>
>
> Now I’m assuming here that HTML Forms do not violate the constraints as well. But HTML Forms seem to be okay [1].
>
> And in OpenSearch with the Parameter Extension[2]:
>
> <Url xmlns:parameters="http://a9.com/-/spec/opensearch/extensions/parameters/1.0/"
>        template="http://example.com/search"
>        parameters:method="POST"
>        parameters:enctype="application/x-www-form-urlencoded">
>     <parameters:Parameter name="q"/>
>     <parameters:Parameter name="count"/>
>     <parameters:Parameter name="start"/>
> </Url>
>
> And finally in Hydra:
>
> {
>     "@context": "http://www.w3.org/ns/hydra/context.jsonld",
>     "@id": "http://example.com/search",
>     "operations": [
>       {
>         "@type": "Search",
>         "method": "POST"
>         "expects" : {
>         	    "@type": "hydra:Class",
>         	    "supportedProperty": [
>                  {
>                      "property": {
>                          "@id": "q",
>                          "@type": "rdf:Property",
>                          "range": "http://www.w3.org/2001/XMLSchema#string"
>                      },
>                      "required": true,
>                      "readonly": false,
>                      "writeonly": false
>                  },
>                  {
>                      "property": {
>                          "@id": "count",
>                          "@type": "rdf:Property",
>                          "range": "http://www.w3.org/2001/XMLSchema#integer"
>                      },
>                      "required": false,
>                      "readonly": false,
>                      "writeonly": false
>                  },
>                  {
>                      "property": {
>                          "@id": "start",
>                          "@type": "rdf:Property",
>                          "range": "http://www.w3.org/2001/XMLSchema#integer"
>                      },
>                      "required": false,
>                      "readonly": false,
>                      "writeonly": false
>                  }
>              ]
>         }
>       }
>     ]
>   }
>
> When I look at all 3, I see a very generic HTTP POST request. Without a doubt, the Hydra version is more expressive we assume that the client will generate JSON-LD request that could also work equally well if it were sent as application/x-www-form-urlencoded. To my tiny monkey brain, these all feel like the same thing and I’m struggling to see how they are different? I am assuming of course that HTML forms DO NOT violate the uniform interface constraint.
>
> Ryan-
>
> [1] http://roy.gbiv.com/untangled/2008/rest-apis-must-be-hypertext-driven
> [2] http://www.opensearch.org/Specifications/OpenSearch/Extensions/Parameter
>
>
> +-----------------------------------------------+
>      Ryan J. McDonough (a.k.a John Yaya)
>      http://damnhandy.com
>      http://twitter.com/damnhandy
>
>

Ryan,

Please include TURTLE examples so that you engage more minds in this 
important discourse :-)

Relation semantics (a really important aspect of any vocabulary or 
ontology construction endeavor) are totally lost when presented as:


{
    "@context": "http://www.w3.org/ns/hydra/context.jsonld",
    "@id": "http://example.com/search",
    "operations": [
      {
        "@type": "Search",
        "method": "POST"
        "expects" : {
        	    "@type": "hydra:Class",
        	    "supportedProperty": [
                 {
                     "property": {
                         "@id": "q",
                         "@type": "rdf:Property",
                         "range": "http://www.w3.org/2001/XMLSchema#string"
                     },
                     "required": true,
                     "readonly": false,
                     "writeonly": false
                 },
                 {
                     "property": {
                         "@id": "count",
                         "@type": "rdf:Property",
                         "range": "http://www.w3.org/2001/XMLSchema#integer"
                     },
                     "required": false,
                     "readonly": false,
                     "writeonly": false
                 },
                 {
                     "property": {
                         "@id": "start",
                         "@type": "rdf:Property",
                         "range": "http://www.w3.org/2001/XMLSchema#integer"
                     },
                     "required": false,
                     "readonly": false,
                     "writeonly": false
                 }
             ]
        }
      }
    ]
  }


-- 

Regards,

Kingsley Idehen	
Founder & CEO
OpenLink Software
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