engine.js

几个运用了DWR框架编写的AJAX代码,

function DWREngine() { }





DWREngine.setErrorHandler = function(handler) {
DWREngine._errorHandler = handler;
};





DWREngine.setWarningHandler = function(handler) {
DWREngine._warningHandler = handler;
};





DWREngine.setTimeout = function(timeout) {
DWREngine._timeout = timeout;
};





DWREngine.setPreHook = function(handler) {
DWREngine._preHook = handler;
};





DWREngine.setPostHook = function(handler) {
DWREngine._postHook = handler;
};


DWREngine.XMLHttpRequest = 1;


DWREngine.IFrame = 2;






DWREngine.setMethod = function(newmethod) {
if (newmethod != DWREngine.XMLHttpRequest && newmethod != DWREngine.IFrame) {
DWREngine._handleError("Remoting method must be one of DWREngine.XMLHttpRequest or DWREngine.IFrame");
return;
}
DWREngine._method = newmethod;
};





DWREngine.setVerb = function(verb) {
if (verb != "GET" && verb != "POST") {
DWREngine._handleError("Remoting verb must be one of GET or POST");
return;
}
DWREngine._verb = verb;
};





DWREngine.setOrdered = function(ordered) {
DWREngine._ordered = ordered;
};





DWREngine.setAsync = function(async) {
DWREngine._async = async;
};





DWREngine.defaultMessageHandler = function(message) {
if (typeof message == "object" && message.name == "Error" && message.description) {
alert("Error: " + message.description);
}
else {
alert(message);
}
};





DWREngine.beginBatch = function() {
if (DWREngine._batch) {
DWREngine._handleError("Batch already started.");
return;
}

DWREngine._batch = {};
DWREngine._batch.map = {};
DWREngine._batch.paramCount = 0;
DWREngine._batch.map.callCount = 0;
DWREngine._batch.ids = [];
DWREngine._batch.preHooks = [];
DWREngine._batch.postHooks = [];
};





DWREngine.endBatch = function(options) {
var batch = DWREngine._batch;
if (batch == null) {
DWREngine._handleError("No batch in progress.");
return;
}

if (options && options.preHook) batch.preHooks.unshift(options.preHook);
if (options && options.postHook) batch.postHooks.push(options.postHook);
if (DWREngine._preHook) batch.preHooks.unshift(DWREngine._preHook);
if (DWREngine._postHook) batch.postHooks.push(DWREngine._postHook);

if (batch.method == null) batch.method = DWREngine._method;
if (batch.verb == null) batch.verb = DWREngine._verb;
if (batch.async == null) batch.async = DWREngine._async;
if (batch.timeout == null) batch.timeout = DWREngine._timeout;

batch.completed = false;


DWREngine._batch = null;



if (!DWREngine._ordered) {
DWREngine._sendData(batch);
DWREngine._batches[DWREngine._batches.length] = batch;
}
else {
if (DWREngine._batches.length == 0) {

DWREngine._sendData(batch);
DWREngine._batches[DWREngine._batches.length] = batch;
}
else {

DWREngine._batchQueue[DWREngine._batchQueue.length] = batch;
}
}
};






DWREngine._errorHandler = DWREngine.defaultMessageHandler;


DWREngine._warningHandler = DWREngine.defaultMessageHandler;


DWREngine._preHook = null;


DWREngine._postHook = null;


DWREngine._batches = [];


DWREngine._batchQueue = [];


DWREngine._handlersMap = {};


DWREngine._method = DWREngine.XMLHttpRequest;


DWREngine._verb = "POST";


DWREngine._ordered = false;


DWREngine._async = true;


DWREngine._batch = null;


DWREngine._timeout = 0;


DWREngine._DOMDocument = ["Msxml2.DOMDocument.5.0", "Msxml2.DOMDocument.4.0", "Msxml2.DOMDocument.3.0", "MSXML2.DOMDocument", "MSXML.DOMDocument", "Microsoft.XMLDOM"];


DWREngine._XMLHTTP = ["Msxml2.XMLHTTP.5.0", "Msxml2.XMLHTTP.4.0", "MSXML2.XMLHTTP.3.0", "MSXML2.XMLHTTP", "Microsoft.XMLHTTP"];










DWREngine._execute = function(path, scriptName, methodName, vararg_params) {
var singleShot = false;
if (DWREngine._batch == null) {
DWREngine.beginBatch();
singleShot = true;
}

var args = [];
for (var i = 0; i < arguments.length - 3; i++) {
args[i] = arguments[i + 3];
}

if (DWREngine._batch.path == null) {
DWREngine._batch.path = path;
}
else {
if (DWREngine._batch.path != path) {
DWREngine._handleError("Can't batch requests to multiple DWR Servlets.");
return;
}
}


var params;
var callData;
var firstArg = args[0];
var lastArg = args[args.length - 1];

if (typeof firstArg == "function") {
callData = { callback:args.shift() };
params = args;
}
else if (typeof lastArg == "function") {
callData = { callback:args.pop() };
params = args;
}
else if (typeof lastArg == "object" && lastArg.callback != null && typeof lastArg.callback == "function") {
callData = args.pop();
params = args;
}
else if (firstArg == null) {



if (lastArg == null && args.length > 2) {
if (DWREngine._warningHandler) {
DWREngine._warningHandler("Ambiguous nulls at start and end of parameter list. Which is the callback function?");
}
}
callData = { callback:args.shift() };
params = args;
}
else if (lastArg == null) {
callData = { callback:args.pop() };
params = args;
}
else {
if (DWREngine._warningHandler) {
DWREngine._warningHandler("Missing callback function or metadata object.");
}
return;
}


var random = Math.floor(Math.random() * 10001);
var id = (random + "_" + new Date().getTime()).toString();
var prefix = "c" + DWREngine._batch.map.callCount + "-";
DWREngine._batch.ids.push(id);


if (callData.method != null) {
DWREngine._batch.method = callData.method;
delete callData.method;
}
if (callData.verb != null) {
DWREngine._batch.verb = callData.verb;
delete callData.verb;
}
if (callData.async != null) {
DWREngine._batch.async = callData.async;
delete callData.async;
}
if (callData.timeout != null) {
DWREngine._batch.timeout = callData.timeout;
delete callData.timeout;
}


if (callData.preHook != null) {
DWREngine._batch.preHooks.unshift(callData.preHook);
delete callData.preHook;
}
if (callData.postHook != null) {
DWREngine._batch.postHooks.push(callData.postHook);
delete callData.postHook;
}


if (callData.errorHandler == null) callData.errorHandler = DWREngine._errorHandler;
if (callData.warningHandler == null) callData.warningHandler = DWREngine._warningHandler;


DWREngine._handlersMap[id] = callData;

DWREngine._batch.map[prefix + "scriptName"] = scriptName;
DWREngine._batch.map[prefix + "methodName"] = methodName;
DWREngine._batch.map[prefix + "id"] = id;


DWREngine._addSerializeFunctions();
for (i = 0; i < params.length; i++) {
DWREngine._serializeAll(DWREngine._batch, [], params[i], prefix + "param" + i);
}
DWREngine._removeSerializeFunctions();


DWREngine._batch.map.callCount++;
if (singleShot) {
DWREngine.endBatch();
}
};




DWREngine._sendData = function(batch) {

if (batch.map.callCount == 0) return;

for (var i = 0; i < batch.preHooks.length; i++) {
batch.preHooks[i]();
}
batch.preHooks = null;

if (batch.timeout && batch.timeout != 0) {
batch.interval = setInterval(function() {
clearInterval(batch.interval);
DWREngine._abortRequest(batch);
}, batch.timeout);
}

var statsInfo;
if (batch.map.callCount == 1) {
statsInfo = batch.map["c0-scriptName"] + "." + batch.map["c0-methodName"] + ".dwr";
}
else {
statsInfo = "Multiple." + batch.map.callCount + ".dwr";
}


if (batch.method == DWREngine.XMLHttpRequest) {
if (window.XMLHttpRequest) {
batch.req = new XMLHttpRequest();
}

else if (window.ActiveXObject && !(navigator.userAgent.indexOf('Mac') >= 0 && navigator.userAgent.indexOf("MSIE") >= 0)) {
batch.req = DWREngine._newActiveXObject(DWREngine._XMLHTTP);
}
}

var query = "";
var prop;
if (batch.req) {
batch.map.xml = "true";

if (batch.async) {
batch.req.onreadystatechange = function() {
DWREngine._stateChange(batch);
};
}

var indexSafari = navigator.userAgent.indexOf('Safari/');
if (indexSafari >= 0) {

var version = navigator.userAgent.substring(indexSafari + 7);
var verNum = parseInt(version, 10);
if (verNum < 400) {
batch.verb == "GET";
}



}
if (batch.verb == "GET") {



batch.map.callCount = "" + batch.map.callCount;

for (prop in batch.map) {
var qkey = encodeURIComponent(prop);
var qval = encodeURIComponent(batch.map[prop]);
if (qval == "") {
if (DWREngine._warningHandler) {
DWREngine._warningHandler("Found empty qval for qkey=" + qkey);
}
}
query += qkey + "=" + qval + "&";
}
query = query.substring(0, query.length - 1);

try {
batch.req.open("GET", batch.path + "/exec/" + statsInfo + "?" + query, batch.async);
batch.req.send(null);
if (!batch.async) {
DWREngine._stateChange(batch);
}
}
catch (ex) {
DWREngine._handleMetaDataError(null, ex);
}
}
else {
for (prop in batch.map) {
if (typeof batch.map[prop] != "function") {
query += prop + "=" + batch.map[prop] + "\n";
}
}

try {




batch.req.open("POST", batch.path + "/exec/" + statsInfo, batch.async);
batch.req.setRequestHeader('Content-Type', 'text/plain');
batch.req.send(query);
if (!batch.async) {
DWREngine._stateChange(batch);
}
}
catch (ex) {
DWREngine._handleMetaDataError(null, ex);
}
}
}
else {
batch.map.xml = "false";
var idname = "dwr-if-" + batch.map["c0-id"];

batch.div = document.createElement('div');
batch.div.innerHTML = "<iframe frameborder='0' width='0' height='0' id='" + idname + "' name='" + idname + "'></iframe>";
document.body.appendChild(batch.div);
batch.iframe = document.getElementById(idname);
batch.iframe.setAttribute('style', 'width:0px; height:0px; border:0px;');

if (batch.verb == "GET") {
for (prop in batch.map) {
if (typeof batch.map[prop] != "function") {
query += encodeURIComponent(prop) + "=" + encodeURIComponent(batch.map[prop]) + "&";
}
}
query = query.substring(0, query.length - 1);

batch.iframe.setAttribute('src', batch.path + "/exec/" + statsInfo + "?" + query);
document.body.appendChild(batch.iframe);
}
else {
batch.form = document.createElement('form');
batch.form.setAttribute('id', 'dwr-form');
batch.form.setAttribute('action', batch.path + "/exec" + statsInfo);
batch.form.setAttribute('target', idname);
batch.form.target = idname;
batch.form.setAttribute('method', 'post');
for (prop in batch.map) {
var formInput = document.createElement('input');
formInput.setAttribute('type', 'hidden');
formInput.setAttribute('name', prop);
formInput.setAttribute('value', batch.map[prop]);
batch.form.appendChild(formInput);
}

document.body.appendChild(batch.form);
batch.form.submit();
}
}
};




DWREngine._stateChange = function(batch) {
if (!batch.completed && batch.req.readyState == 4) {
try {
var reply = batch.req.responseText;
var status = batch.req.status;

if (reply == null || reply == "") {
DWREngine._handleMetaDataError(null, "No data received from server");
return;
}