Content-type filtering in @RequestMapping [SPR-5623]

[spring-projects-issues]

Arjen Poutsma opened SPR-5623 and commented

It would be useful to customize the view resolution/content negotiation in the @RequestMapping annotation, by picking a response content-type there. Something like:

@RequestMapping(value = "/hotels", contentType="application/pdf")

This contentType would directly influence the View that is picked by the ViewResolver.

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Issue Links:

• Request header filtering in @RequestMapping [SPR-5690] #10360 Request header filtering in @RequestMapping

3 votes, 3 watchers

[spring-projects-issues]

Grzegorz Borkowski commented

There can be two approaches for this.

1. Add 'header' field to ReqestMapping annotation, eg.
   @RequestMapping(value = "/hotels", header = "accept=application/pdf")

This is more generic and powerful, because any header can be matched. But the syntax is a bit awkward (perhaps split it into 'header' and 'headerValue' ? header = "accept", headerValue="application/pdf"). And probability of using other headers then content-type is much smaller (though I can imaging usage of accept-language, accept-encoding headers).

2.The one described in original request: add 'contentType' field to annotation:
@RequestMapping(value = "/hotels", contentType="application/pdf")
This is less powerful, but can be more practical in about 80% of cases, as it's cleaner and less error-prone.

Perhaps both can be implemented: contentType and header. ContentType param would have higher priority if both were used on the same annotation and 'header' also targeted content-type.

[spring-projects-issues]

Arjen Poutsma commented

I've created a separate issue for the request header filtering (#10360), since that is not really related to response content-type filtering.

[spring-projects-issues]

Arjen Poutsma commented

I think that specifying the response content type in the Request Mapping does not make a lot of sense. We might want to introduce another annotation for it, or simply add a content-type property to ModelAndView. So that you would be able to do something like:

@RequestMapping(value = "/something", headers="accept=text/html")
public ModelAndView handleHtml() {
  ModelAndView mav = new ModelAndView();
  mav.setContentType("text/html");
  return mav;
}

Overall, I need to think about this a bit more...

[spring-projects-issues]

Arjen Poutsma commented

After talking this over with Juergen, we don't see what this approach adds to the current way of explicitly picking a View in the handler method. For instance:

@RequestMapping(value = "/something", headers="accept=text/html")
public View handleHtml() {
  // ...
  ModelAndView mav = new ModelAndView();
  mav.setView(new MarshallerView(myMarshaller));
  mav.addObject(myModelObject);
  return mav;
}

In our opinion, this is much clearer and less magical.