RE: Representing HTTP forms in Hydra

The long and short of it is we have HTML clients that can only send
application/x-www-form-urlencoded request to the service. Rather than proxy
the request through the web application I'd rather have the HTML client
send the data directly to the service.

I need to be able to map form fields to RDF properties so we don't lose the
semantics.  We have that with IriTemplates but not with request payloads.

The reason we need this is less about describing legacy APIs and more able
enabling server-side web apps (think PHP, Django, Rails, etc) to construct
HTML clients with just HTML for graceful degradation without tunneling the
request through the server-side app.

Perhaps this is not the responsibility of Hydra and a separate HTML form to
RDF property vocabulary is needed.  I'll leave that to the community it
decide.

Does that help?

Thanks,
Eric Moritz.

On Apr 10, 2014 5:58 AM, "Markus Lanthaler" <markus.lanthaler@gmx.net>
wrote:
>
> Hi Eric,
>
> Sorry for the delay... unfortunately I have to say that quite often
recently
> :-(
>
> On Monday, March 31, 2014 5:30 PM, Eric Moritz wrote:
> > Hi I would like to describe an application/x-www/form-urlencoded form
> > much like I can for IRI templates.  What I have been using is the
> > hydra:supportedProperty property on a  hydra:Class.
> >
> > For instance this is my form being POSTed to the service:
> >
> >
> > cookieService:CookiesForm
> >      rdfs:type hydra:Class ;
> >      rdfs:comment "The cookie form can be submitted with "
> >
> >      hydra:supportedProperty [
> >          rdfs:type hydra:SupportedProperty
> >          rdfs:comment "The _method hack for non-RESTful clients"
> >          hydra:property cookieService:method
> >          hydra:variable "_method"
> >      ] ;
> >
> >      hydra:supportedProperty [
> >            rdfs:type hydra:SupportedProperty ;
> >            rdfs:comment "URL to redirect to" ;
> >            hydra:property http:location ;
> >            hydra:variable "location"
> >      ] ;
> >
> >      hydra:supportedProperty [
> >            rdfs:type hydra:SupportedProperty ;
> >            rdfs:comment "The content type to return; supported content
> >              types are 'text/html' and 'application/json'" ;
> >            hydra:property http:accept ;
> >            hydra:variable "accept"
> >      ] .
> >
> > I noticed that hydra:variable has a domain of hydra:IriTemplateMapping
> > which turns the range of the hydra:supportedProperty into a
> > hydra:IriTemplateMapping; which it is not.
>
> Right.. we could however, introduce something like hydra:parameterName.
We'd
> also need to describe something on the operation level to indicate that
the
> server expects a application/x-www-form-urlencoded string instead of
JSON-LD
> payload.
>
>
> > Our clients are a mix of HTML, JSON and Linked Data clients so I would
> > like to be able to describe how HTML clients can be rendered using
> > Hydra.
>
> The alternative is to dynamically construct a JSON-LD payload when the
form
> is submitted. That's basically what I do in the Hydra console. Obviously
> that doesn't help if your server doesn't understand JSON-LD at all (e.g.,
> because it is a legacy API). Is that the reason why you want urlencoded
> forms?
>
>
> > Is it possible to describe how to construct a application/x-www/form-
> > urlencoded using Hydra like we can for an Iri Template?
>
> Currently it isn't but if people ask for it, we could certainly add it.
> Could you please elaborate a bit on why you need it and why you don't want
> to send JSON-LD payloads?
>
>
> Thanks,
> Markus
>
>
>
> --
> Markus Lanthaler
> @markuslanthaler
>