I'm building and iOS application and trying to get the json data from a url similar to:
example.com/ajax/u.php?callback=jQuery84054761566_1389381628746
Is anyone familiar with these types of callbacks?
Typical HTTP requests in obj-c return 200 status and a null response object with this url.
That's a JSONP callback used for...well, JSONP. JSONP is used on webpages to avoid the 'same origin' restriction. That is, a webpage loaded from a certain domain (say abc.com) cannot call/access resources on a separate domain (say xyz.com).
The way they (web front-end developers) get around this is by using the <script> tag which is exempt from this restriction. However the return of a <script> tag would just be parsed - to cause it to execute something, you tell it a function name that exists in your JavaScript code, in this case, jQuery84054761566_1389381628746.
So instead of returning a regular JavaScript object, say
{key : 'value'}
the server then returns a function invocation
jQuery84054761566_1389381628746({key : 'value'})
and you have, in your webpage JavaScript, the function definition for jQuery84054761566_1389381628746 that does something:
jQuery84054761566_1389381628746 = function(data){
alert(data.key);
};
iOS does not have this same-origin/cross-site restriction so you don't need JSONP - you can call whatever server you want.