parsing JSONP $http.jsonp() response in angular.js

I am using angular's $http.jsonp() request which is successfully returning json wrapped in a function:

var url = "http://public-api.wordpress.com/rest/v1/sites/wtmpeachtest.wordpress.com/posts?callback=jsonp_callback";

$http.jsonp(url).
    success(function(data, status, headers, config) {
        //what do I do here?
    }).
    error(function(data, status, headers, config) {
        $scope.error = true;
    });

How to access/parse the returned function-wrapped-JSON?

UPDATE: since Angular 1.6

You can no longer use the JSON_CALLBACK string as a placeholder for specifying where the callback parameter value should go

You must now define the callback like so:

$http.jsonp('some/trusted/url', {jsonpCallbackParam: 'callback'})

Change/access/declare param via $http.defaults.jsonpCallbackParam, defaults to callback

Note: You must also make sure your URL is added to the trusted/whitelist:

$sceDelegateProvider.resourceUrlWhitelist

or explicitly trusted via:

$sce.trustAsResourceUrl(url)

success/error were deprecated.

The $http legacy promise methods success and error have been deprecated and will be removed in v1.6.0. Use the standard then method instead. If $httpProvider.useLegacyPromiseExtensions is set to false then these methods will throw $http/legacy error.

USE:

var url = "http://public-api.wordpress.com/rest/v1/sites/wtmpeachtest.wordpress.com/posts"
var trustedUrl = $sce.trustAsResourceUrl(url);

$http.jsonp(trustedUrl, {jsonpCallbackParam: 'callback'})
    .then(function(data){
        console.log(data.found);
    });

Previous Answer: Angular 1.5.x and before

All you should have to do is change callback=jsonp_callback to callback=JSON_CALLBACK like so:

var url = "http://public-api.wordpress.com/rest/v1/sites/wtmpeachtest.wordpress.com/posts?callback=JSON_CALLBACK";

And then your .success function should fire like you have it if the return was successful.

Doing it this way keeps you from having to dirty up the global space. This is documented in the AngularJS documentation here.

Updated Matt Ball's fiddle to use this method: http://jsfiddle.net/subhaze/a4Rc2/114/

Full example:

var url = "http://public-api.wordpress.com/rest/v1/sites/wtmpeachtest.wordpress.com/posts?callback=JSON_CALLBACK";

$http.jsonp(url)
    .success(function(data){
        console.log(data.found);
    });

The MOST IMPORTANT THING I didn't understand for quite awhile is that the request MUST contain "callback=JSON_CALLBACK", because AngularJS modifies the request url, substituting a unique identifier for "JSON_CALLBACK". The server response must use the value of the 'callback' parameter instead of hard coding "JSON_CALLBACK":

JSON_CALLBACK(json_response);  // wrong!

Since I was writing my own PHP server script, I thought I knew what function name it wanted and didn't need to pass "callback=JSON_CALLBACK" in the request. Big mistake!

AngularJS replaces "JSON_CALLBACK" in the request with a unique function name (like "callback=angular.callbacks._0"), and the server response must return that value:

angular.callbacks._0(json_response);

This was very helpful. Angular doesn't work exactly like JQuery. It has its own jsonp() method, which indeed requires "&callback=JSON_CALLBACK" at the end of the query string. Here's an example:

var librivoxSearch = angular.module('librivoxSearch', []);
librivoxSearch.controller('librivoxSearchController', function ($scope, $http) {
    $http.jsonp('http://librivox.org/api/feed/audiobooks/author/Melville?format=jsonp&callback=JSON_CALLBACK').success(function (data) {
        $scope.data = data;
    });
});

Then display or manipulate {{ data }} in your Angular template.

This should work just fine for you, so long as the function jsonp_callback is visible in the global scope:

function jsonp_callback(data) {
    // returning from async callbacks is (generally) meaningless
    console.log(data.found);
}

var url = "http://public-api.wordpress.com/rest/v1/sites/wtmpeachtest.wordpress.com/posts?callback=jsonp_callback";

$http.jsonp(url);

Full demo: http://jsfiddle.net/mattball/a4Rc2/ (disclaimer: I've never written any AngularJS code before)

You still need to set callback in the params:

var params = {
  'a': b,
  'token_auth': TOKEN,
  'callback': 'functionName'
};
$sce.trustAsResourceUrl(url);

$http.jsonp(url, {
  params: params
});

Where 'functionName' is a stringified reference to globally defined function. You can define it outside of your angular script and then redefine it in your module.