JSL - AJAX plugin

An AJAX plugin for JSL

Dieses Skript sollte nicht direkt installiert werden. Es handelt sich hier um eine Bibliothek für andere Skripte, welche über folgenden Befehl in den Metadaten eines Skriptes eingebunden wird // @require https://update.greasyfork.org/scripts/2817/7911/JSL%20-%20AJAX%20plugin.js

// ==UserScript==
// @name          JSL - AJAX plugin
// @namespace     http://userscripts.org/users/23652
// @description   An AJAX plugin for JSL
// @include       *
// @version       1.1.0
// @grant         GM_xmlhttpRequest
// ==/UserScript==

/* CHANGELOG

1.1.0 (3/28/2014)
    - added JSL.ajaxClear() to clear all current and pending requests

1.0.21 (10/6/2013)
    - fixed bug with .clear()

1.0.2 (10/6/2013)
    - added a new option: async
        false (default) ==> synchronous, but non-freezing requests (sequential)
            waits for previous request to finish before starting a new one
        true ==> sends all requests immediately when they are added to the queue
    - fixed delay issue.
        the next request would get run on the 'onprogress' & 'onreadystatechange' events
        instead of when they actually load fully
    - added a .clear() method
        it may be called on any ajax instance like JSL.ajax(...).clear()
        it can even simply be called as JSL.ajax().clear()
        it will clear ALL requests at the moment

1.0.1 (10/3/2013)
    - fixed small bug with passing a url array
    - fixed bug not allowing HEAD requests to be recognized

1.0.0 (10/1/2013)
    - created

*/

(function (undefined) {

    'use strict'; // use strict mode in ECMAScript-5

    var queue = [],               // the request queue
        blank = function () {},   // blank function to use as default callback
        xhrInProgress = false,    // boolean to know if we should load the next request
        xhrCleared = false;       // boolean to know if the xhr has been cleared and if
                                  //     we should execute any of the callbacks

    var core = {
        // object
        'hasOwnProperty' : Object.prototype.hasOwnProperty
    };

    function copyObject(o) {
        var key, value, newO = {};

        for (key in o) {
            value = o[key];

            if (core.hasOwnProperty.call(o, key) && value != null) {
                newO[key] = value;
            }
        }

        return newO;
    }

    function toDataString(o) {
        var key, value, dataString = '';

        for (key in o) {
            value = o[key];

            if (core.hasOwnProperty.call(o, key) && value != null) {
                dataString += key + '=' + encodeURIComponent(value) + '&';
            }
        }

        return dataString.slice(0, -1);
    }

    function xhr() {
        var req = queue[0], // get the object which is first in the queue
            xhrObj = {}, key;

        function handleEvents(type, resp, event) {
            var event = event || {}, newResp, context;
                req.delay = req.delay > 15 ? req.delay : 15; // don't want to mess up callbacks

            if (xhrCleared === true) {
                return;
            }

            if (req[type] !== blank) {
                // define a new response object to give to the user
                newResp = {
                    lengthComputable : resp.lengthComputable || event.lengthComputable || null,
                    loaded : resp.loaded || event.loaded || null,
                    readyState : resp.readyState,
                    responseHeaders : resp.responseHeaders ||
                        ( typeof resp.getAllResponseHeaders === 'function' ? resp.getAllResponseHeaders() : null) || '',
                    responseText : resp.responseText,
                    status : resp.status,
                    statusText : resp.statusText,
                    total : resp.total || event.total || null,
                    url : resp.finalUrl || req.url,
                };

                // allow new requests to be run if our request is done
                if (type === 'onerror' || type === 'onload') {
                    xhrInProgress = false;

                    // run the next in queue, if any
                    window.setTimeout(xhr, req.delay);
                }

                // run the callback
                context = req.context || newResp;
                req[type].call(context, newResp);
            }
        }

        if ( req && (xhrInProgress === false || req.async === true) && queue.length > 0) {
            // make it so no other requests get run while we
            // run this one, if async isn't enabled
            xhrInProgress = true;

            // remove the first item in the queue if it is going to be run
            queue.shift();

            if (typeof GM_xmlhttpRequest === 'function') {
                if (req.method.toUpperCase() === 'GET' && req.data !== '') {
                    req.url += '?' + req.data;
                    req.data = '';
                }

                GM_xmlhttpRequest({
                    'data' : req.data,
                    'headers' : req.headers,
                    'method' : req.method,
                    'onerror' : function (resp) {
                        handleEvents('onerror', resp);
                    },
                    'onload' : function (resp) {
                        handleEvents('onload', resp);
                    },
                    'onreadystatechange' : function (resp) {
                        handleEvents('onreadystatechange', resp);
                    },
                    'onprogress' : function (resp) {
                        handleEvents('onprogress', resp);
                    },
                    'url' : req.url,
                });
            } else if (typeof XMLHttpRequest === 'function' || typeof ActiveXObject === 'function') {
                xhrObj = XMLHttpRequest ? new XMLHttpRequest() : new ActiveXObject('Microsoft.XMLHTTP');

                // set events
                xhrObj.onload = function (resp) {
                    handleEvents('onload', xhrObj);
                };
                xhrObj.onerror = function (resp) {
                    handleEvents('onerror', xhrObj);
                };
                xhrObj.onprogress = function (resp) {
                    handleEvents('onprogress', xhrObj, resp);
                };

                if (req.mimeType !== '') {
                    xhrObj.overrideMimeType(req.mimeType);
                }

                // add headers
                for (key in req.headers) {
                    xhrObj.setRequestHeader( key, req.headers[key] );
                }

                xhrObj.open(req.method, req.url, true);
                xhrObj.send( (req.data || null) );
            }
        }
    }

    function init(url, settings) {
        var urls = [],
            realSettings = { // defaults
                async : false,
                data : '',
                headers : {},
                method : 'GET',
                mimeType : '',
                onload : blank,
                onerror : blank,
                onprogress : blank,
                onreadystatechange : blank,
                delay : 0
            },
            key, value;

        if (typeof url === 'string') {
            urls.push(url);
        } else if (JSL.typeOf(url) === 'array') {
            urls = urls.concat(url);
        }

        if (JSL.typeOf(settings) === 'object') {
            for (key in settings) {
                value = settings[key];

                switch (key) {
                    case 'async': {
                        if (typeof value === 'boolean') {
                            realSettings[key] = value;
                        }
                        break;
                    }
                    case 'context': {
                        if (value != null) {
                            realSettings[key] = value;
                        }
                        break;
                    }
                    case 'data': {
                        if (typeof value === 'string') {
                            realSettings[key] = value;
                        } else if (JSL.typeOf(value) === 'object') {
                            realSettings[key] = toDataString(value);
                        }
                        break;
                    }
                    case 'delay': {
                        if (typeof value === 'number' && value > 0) {
                            realSettings[key] = value;
                        }
                        break;
                    }
                    case 'headers': {
                        if (JSL.typeOf(value) === 'object') {
                            realSettings[key] = toDataString(value);
                        }
                        break;
                    }
                    case 'method': {
                        if ( typeof value === 'string' && /get|post|head/i.test(value) ) {
                            realSettings[key] = value.toUpperCase();
                        }
                        break;
                    }
                    case 'mimeType': {
                        if (typeof value === 'string') {
                            realSettings[key] = value;
                        }
                        break;
                    }
                    case 'onload': case 'onerror': case 'onreadystatechange': case 'onprogress': {
                        if (typeof value === 'function') {
                            realSettings[key] = value;
                        }
                        break;
                    }
                }
            }
        }

        // add an object to the queue for each url
        if (urls.length > 0) {
            JSL.each(urls, function (url) {
                var newO = copyObject(realSettings);
                newO.url = url;
                queue.push(newO);
            });

            // enable ajax if it was cleared earlier
            xhrCleared = false;

            // run the xhr function
            // it will determine whether or not a request needs to be sent
            xhr();
        }
    }

    init.prototype = {
        constructor: init,

        clear : function() {
            queue.length = 0;
            xhrInProgress = false;
            xhrCleared = true;
        },

        get length() {
            return queue.length;
        }
    };

    JSL.extend({
        ajax : function (url, settings) {
            return new init(url, settings);
        },
        ajaxClear : init.prototype.clear
    });

}());