Ajax transport example for json, for ajax caching.

ajaxCacheTransport.js

/**
 * This function performs the fetch from cache portion of the functionality needed to cache ajax
 * calls and still fulfill the jqXHR Deferred Promise interface.
 * See also $.ajaxPrefilter
 * @method $.ajaxTransport
 * @params options {Object} Options for the ajax call, modified with ajax standard settings
 */
$.ajaxTransport("json", function(options){
    if (options.localCache)
    {
        var cacheKey = options.cacheKey ||
            options.url.replace(/jQuery.*/, '') + options.type + options.data;

        var value = storage.getItem(cacheKey);
        if (value){
            // In the cache? Get it, parse it to json, call the completeCallback with the fetched value.
            if (options.dataType.indexOf( 'json' ) === 0) value = JSON.parse(value);
            return {
                send: function(headers, completeCallback) {
                    completeCallback(200, 'success', {json:value})
                },
                abort: function() {
                    console.log("Aborted ajax transport for json cache.");
                }
            };
        }
    }
});