Question

Google returns Unparsable Cuft to the json response like this:

throw 1; <dont be evil> { foo: bar}

• My current web applications use jQuery.Ajax to retrieve JSON data. How should they be modified to consume valid data?

Here is a relevant demo

Answer 1

You should probably remove the beginning part from the response:

$.ajax(url, {
    dataType: "jsonp text",
    success: function(data) {
        var jsonString = data.replace(/^throw 1; <dont be evil> /, "");
        var responseObject = $.parseJSON(jsonString);

        // do something with responseObject
        ...
    }
}

UPDATE:

To make the re-writing available in every Ajax call you could also register a global Ajax Converter in jQuery:

$.ajaxSetup({
    converters: {
        "text cleanedjson": function(data) {
            var jsonString = data.replace(/^throw 1; <dont be evil> /, "");
            return $.parseJSON(jsonString);
        }
    }
});

$.ajax(url, {
    dataType: "jsonp cleanedjson",
    success: function(responseObject) {
        // do something with responseObject
        ...
    }
});

You will still need to specify your defined dataType in the request options.

UPDATE 2:
If you need to tweak your existing calls to do the response cleanup automatically, you could patch jQuery’s ajax implementation to automatically use your converter in certain situations:

// store reference to original implementation
$._ajax_original = $.ajax;

// redefine jQuery's ajax function
$.ajax = function(url, settings) {
    if (… your test for applicability here (e.g. an url check) …) {
        settings.dataType = "jsonp cleanedjson";
    }
    return $._ajax_original(url, settings);
};

​
Note that this redefinition has to included after loading jQuery and before the first Ajax call is made. You may also need to consider that $.ajax can also be called without a separate url parameter…