Cross domain JsonP RSS

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  ThatsIT

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  Cross domain JsonP

  Mar 14, 2012 12:43 PM|LINK

  How does Jsonp work cross domain, i had a quick sample to see if i could solve a problem using code below access both a web api controler and a mvc controller return jsonresult. both returned the correct data in responsebody, but sucess function would not fire.

  Any ideas?
  Thanks

   

  $(document).ready(function () {
          alert("")
          $.ajax({
              url: 'http://localhost:5656/perth/api?callback=?',
              type: "GET",
              dataType: "jsonp",
              success: function (data) {
                  alert(data)
                  $('#divContent').append(data);
              }
          });
      });

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  awebb

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  Re: Cross domain JsonP

  Mar 14, 2012 01:09 PM|LINK

  Doesn't jQuery add the "?callback=?" part for you?

  Andrew
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  ThatsIT

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  Re: Cross domain JsonP

  Mar 14, 2012 01:11 PM|LINK

  I tried with and without still no luck

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  awebb

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  Re: Cross domain JsonP

  Mar 14, 2012 01:17 PM|LINK

  And the endpoint you're hitting is definitely set up to do JSONP?  I.e. returning JSON specifed as an arg to a function call?

  What if you knocked up an HTML page with a <script> tag in it that hits your endpoint (with suitable "?callback=fnName" appended) - what is returned?

  Do you need to specify "crossDomain: true" in your call, to allow the server to do a redirect to another domain?

  If the server endpoint is set up to do JSONP, is it taking the function name from the callback= query string?  It would be a mistake if it used a hardwired name (e.g. "success").

  Andrew
  • Edited by awebb on Mar 14, 2012 01:22 PM
  • Edited by awebb on Mar 14, 2012 01:23 PM
  • Edited by awebb on Mar 14, 2012 01:28 PM
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  ThatsIT

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  Re: Cross domain JsonP

  Mar 14, 2012 01:41 PM|LINK

  using this ajax

  $(document).ready(function () {
          alert("")
          $.ajax({
              url: 'http://localhost:2131/api/values/1',
              type: "GET",
              dataType: "jsonp",
              success: function (data) {
                  alert(data)
                  $('#divContent').append(data);
              }
          });
      });

  This is the request sent
  http://localhost:2131/api/values/1?callback=jQuery162011628848609451742_1331731933864&_=1331731937032 

  and this is the respnse body

  "<iframe width=\"420\" height=\"315\" src=\"http:\/\/www.youtube.com\/embed\/-Xu71i89xvs\" frameborder=\"0\" allowfullscreen><\/iframe>"

  the same is returned using scriopt tag.

  As for the controller being setuo to do jsonp, no i dont know. I have used a simple api get method returning string, and i have used a mvc action returning json, neither fire.

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  SiggiGG

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  Re: Cross domain JsonP

  Mar 14, 2012 01:46 PM|LINK

  Andrew, jQuery handles wiring all that up for you automatically and as far as I can see he's wiring this up correctly.
  http://api.jquery.com/jQuery.ajax/

  My guess is the service isn't returning actual JSONP data?

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  SiggiGG

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  Re: Cross domain JsonP

  Mar 14, 2012 01:49 PM|LINK

  ThatsIT

  As for the controller being setuo to do jsonp, no i dont know. I have used a simple api get method returning string, and i have used a mvc action returning json, neither fire.

  The request URL looks right, but the return data is not, this is definnitely not JSONP :)

  JSONP handlers looks for the callback=something parameter in the query string and uses that name to name the Javascript method that's created to wrap the JSON data.
  JSONP is basically a hack to get data cross-domain by using the browser's ability to load Javascript over cross-domain boundaries.

  JSONP isn't supported "out of the box" with ASP.NET Web API YET, but here's a sample to get you started:
  http://stackoverflow.com/questions/9421312/jsonp-with-mvc-4-webapi

  • Edited by SiggiGG on Mar 14, 2012 01:52 PM
  • Edited by SiggiGG on Mar 14, 2012 01:52 PM
  • Edited by SiggiGG on Mar 14, 2012 01:53 PM
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  awebb

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  Re: Cross domain JsonP

  Mar 14, 2012 01:52 PM|LINK

  SiggiGG

  jQuery handles wiring all that up for you automatically and as far as I can see he's wiring this up correctly

  I know that it's wired up automatically.  His request (in the original post) is incorrect in that it shouldn't append ?callback=?

  SiggiGG

  My guess is the service isn't returning actual JSONP data?

  Totally.

  Andrew
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  ThatsIT

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  Re: Cross domain JsonP

  Mar 14, 2012 01:53 PM|LINK

  this is what i get back using my mvc controller returning json
  

  "\u003ciframe width=\"420\" height=\"315\" src=\"http://www.youtube.com/embed/-Xu71i89xvs\" frameborder=\"0\" allowfullscreen\u003e\u003c/iframe\u003e"

   

  any ideas how I return jsonp, i have never used it before

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  SiggiGG

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  105 Posts

  Re: Cross domain JsonP

  Mar 14, 2012 01:53 PM|LINK

  ThatsIT

  any ideas how I return jsonp, i have never used it before

  See my reply above, I just included a link to a solution.