Responses support errors

[GoogleCodeExporter]

Hello,

I added validations to a domain class that I generated resources for. when one 
of the validations is violated on POST call, the generated resource crashes, 
because it is not automatically taking care of errors. 

It would be nice if the plugin generated something like this:

 @POST
    Response create(foo dto) {
        FooResourceService.create(dto)
        if (dto.errors.errorCount == 0) 
        {
            created dto
        }
        else
        {
            error dto.errors
         }
    }

Original issue reported on code.google.com by k...@pros.com on 15 Feb 2012 at 5:33

[GoogleCodeExporter]

It's a good idea to add something like that but what response code to return?

- just 400 ? (bad request)
- or 409 ? (conflict)
- or 412 ? (precondition failed)
- or ...

This is often very application-specific (depending on the validation error) but 
one could have generic error handling in the templates for the most obvious 
cases.

Do you want to make a proposal how to handle that and create a patch or pull 
request?

Thanks for sharing your ideas.

Cheers,
Martin

Original comment by krass...@googlemail.com on 16 Feb 2012 at 6:54

[GoogleCodeExporter]

Hello,

I think minimally 400 Bad Request would be good for validation errors. Googling 
around, this seems to be the consensus (the books I've read are a little vague  
about this).

I modified my *Resource.groovy classes to do this (see below). It would be nice 
if this code were buried in the "Responses" class like "ok" and "created". The 
big thing is to get the "errors" from the domain object marshaled back easily.

I am a little new at Grails/Groovy, so I wound up doing the code below. I could 
probably put something in "Responses", but the generated resource class I think 
needs to make the decision whether its bad or not. I do not think you could 
make that decision in "ok"
 or "created" - too late.

Thanks,
Kurt

    @PUT
    @Produces('application/json')
    Response updateJson(User dto) {
        def errorRender = { updUser -> error updUser.errors as JSON }
        saveUser(dto, errorRender)
    }

    @PUT
    @Produces('application/xml')
    Response updateXml(User dto) {
        def errorRender = { updUser -> error updUser.errors as XML }
        saveUser(dto, errorRender)
    }
    private saveUser(User dto, def errorRender) {
        dto.id = id
        def updUser = userResourceService.update(dto)
        if (updUser.errors.errorCount == 0)
        {
            ok updUser
        }
        else
        {
            errorRender(updUser)
        }
    }

    static Response error(def resource)
    {
        Response.serverError().entity(resource).build()
    }

Original comment by k...@pros.com on 16 Feb 2012 at 3:32