JQuery getJSON function

Question

Hello,

I am using the following code to get the json feed of a twitter users friends using the twitter api :

var url = "http://twitter.com/statuses/friends/"+twitter_handle+".json?callback=?";

//show ajax loading animation
$('#loading').show();

$.getJSON(url, function(data) {
   //hide ajax loading animation 
   $('#loading').hide();
   //Processing the JSON here
   //...
});

This works when the twitter handle is valid.But if it is invalid,i.e. when no such twitter user exists the callback function i defined is not executed, and the ajax loading animation does not get hidden.

So, is there a way i can determine in code whether the request for the json feed is failing,and then hide the loading animation ?

Thank You.

Answer 1

the ccallback can return 2 arguments one of which is a textStatus that you can test against.

$.getJSON(url, function (data, textStatus) {
  // data will be a jsonObj
  // textStatus will be one of the following values: 
  //   "timeout","error","notmodified","success","parsererror"
  this; // the options for this ajax request
}

via: http://docs.jquery.com/Ajax/jQuery.getJSON

Answer 2

You are not catching the error condition. From the example below you can use an if statement or a switch to handle both situations.

http://docs.jquery.com/Ajax/jQuery.getJSON says:

callback (Optional) Function A function to be executed whenever the data is loaded successfully.

function (data, textStatus) {
  // data will be a jsonObj
  // textStatus will be one of the following values: 
  //   "timeout","error","notmodified","success","parsererror"
  this; // the options for this ajax request
}

Edit Working Example thanks go to http://stackoverflow.com/questions/1002367/jquery-ajax-jsonp-ignores-a-timeout-and-doesnt-fire-the-error-event.

  var twitter_handle = 'FakePersonx';
  var url = "http://twitter.com/statuses/friends/"+twitter_handle+".json?callback=?";

  $.jsonp({
   type: "GET",
   url: url,
   data: {},
   async:true,
   contentType: "application/json; charset=utf-8",
   dataType: "jsonp",
   success: function(data) {
    alert(data);
   },
   error: function (XMLHttpRequest, textStatus, errorThrown) {
    alert('error');
   },
   beforeSend: function (XMLHttpRequest) {
    alert('Before Send');
    $('#loading').show();
   },
   complete: function (XMLHttpRequest, textStatus) {
    alert('Complete');
    $('#loading').hide();
   }
});