An Ajax connection pool Encapsulation

1. Source Code

 

This Ajax connection pool has caused me a long time. Finally, it is compatible with four types of browsers: IE6/7/8, Firefox, opera, and Google Chrome.

 

/** <Br/> * Ajax connection pool <br/> * ajaxconnectionpool build in 2009.7.10 <br/> * @ author codingmouse <br/> * @ version 1.0 <br/> * /<br/> var ajaxconnectionpool = function () {</P> <p> // task queue <br/> var taskqueue = []; <br/> // Request Buffer Pool <br/> var requestbufferpool = []; <br/> // maximum number of connections <br/> var maxthreadnumber = 2; </P> <p> return {<br/>/** <br/> * obtain idle requests <br/> * @ return {idle request object} <br/> */<br/> getidlerequest: function () {<Br/> var request = NULL; <br/> for (VAR I = 0; I <maxthreadnumber; I ++) {<br/> If (requestbufferpool [I]. readystate = 0) {<br/> request = requestbufferpool [I]; <br/> break; <br/>}< br/> return request; <br/> }, <br/>/** <br/> * initialization <br/> * @ Param {maximum number of connections} max <br/> */<br/> init: function (max) {<br/> If (max! = NULL) <br/> maxthreadnumber = max; <br/> for (var k = 0; k <maxthreadnumber; k ++) {<br/> var request = NULL; <br/> If (window. XMLHttpRequest) {// for Google Chrome, Mozilla Firefox, Netscape, opera 8.0 +, Safari, IE7 +, and other browsers <br/> request = new XMLHttpRequest (); <br/> If (request. overridemimetype) {// set the mime Category <br/>/* <br/> * some versions of browsers do not contain XML mime-type header returned by the processing server <br/> * will report an error, therefore, make sure that the returned content contains text/XML Information.. <Br/> */<br/> request. overridemimetype ("text/XML"); <br/>}< br/>} else if (window. activexobject) {// for Internet Explorer 6.0-browser <br/> var MSXML = [<br/> "msxml2.xmlhttp. 6.0 ", <br/>" msxml2.xmlhttp. 5.0 ", <br/>" msxml2.xmlhttp. 4.0 ", <br/>" msxml2.xmlhttp. 3.0 ", <br/>" msxml2.xmlhttp ", <br/>" Microsoft. XMLHTTP "]; <br/> for (VAR I = 0; I <MSXML. length; I ++) {<br/> try {<br/> request = new activexobject (MSXML [I]); <br/> break; <br/>}catch (e) {<br/> request = NULL; <br/>}< br/> If (request = NULL) {<br/> alert ("Sorry! Because you are using a browser that does not support Ajax, the server can not process a request submitted! "); <Br/> return; <br/>}< br/> requestbufferpool. push (request); <br/>}< br/> }, <br/>/** <br/> * obtain the browser type <br/> * @ return {string of the browser type} <br/> */<br/> getbrowsertype: function () {</P> <p> If (navigator. useragent. indexof ("MSIE")> 0) {<br/> return "MSIE"; // IE browser <br/>} else if (navigator. useragent. indexof ("Firefox")> 0) {<br/> return "Firefox"; // Firefox browser <br/>} else if (navigator. useragent. index Of ("safari")> 0) {<br/> return "safari"; // safan browser <br/>} else if (navigator. useragent. indexof ("Camino")> 0) {<br/> return "Camino"; // Camino browser <br/>} else if (navigator. useragent. indexof ("Gecko/")> 0) {<br/> return "gecko"; // gecko browser <br/>} else {<br/> return "unknown "; // unknown browser <br/>}</P> <p> }, <br/>/** <br/> * send a request <br/> * @ Param {Request Method post | get} method <br/> *@ param {request URL address} u RL <br/> * @ Param {data} data <br/> * @ Param {callback function} callback <br/> * @ Param {scope} scope <br/> * @ Param {whether to send an asynchronous request, note: The callback method true | false} isasync <br/> */<br/> send: function (method, URL, Data, callback, scope, isasync) {</P> <p> // XML callback handle <br/> var xmlcallbackhandler = function () {<br/> If (request. readystate <4) {<br/> window. status = "loading... "; <br/>} else if (request. readystat E = 4) {<br/> If (request. status = 200) {<br/> window. status = "finished. "; <br/> If (handler. func! = NULL) {<br/> handler. func. Call (handler. Scope! = NULL <br/>? Handler. scope <br/>: window, request. responsetext, <br/> request. responsexml, request. status); <br/>}< br/> request. abort (); <br/> If (taskqueue. length> 0) {<br/> // multiple tasks are waiting for connection in the queue. Run the first task <br/> var task = taskqueue. shift (); <br/> ajaxconnectionpool. send (task. method, task. URL, task. data, <br/> task. callback, task. scope, isasync); <br/>}< br/>} else if (request. status = 404) {<br/> window. status = "Requested URL is not found. "; <br/> alert (" requested URL is not found. "); <br/>} else if (request. status = 403) {<br/> window. status = "Access denied. "; <br/> alert (" Access denied. "); <br/>}else {<br/> window. status = "requested status is" + request. status; <br/> alert ("requested status is" + request. status); <br/>}< br/>}else {<br/> (function () {<br/> throw request. status; <br/> }). call (handl Er. Scope! = NULL? Handler. scope: Window); <br/>}< br/>}; </P> <p> // obtain idle requests <br/> var request = ajaxconnectionpool. getidlerequest (); <br/> // This is an idle request <br/> If (request! = NULL) {<br/> var handler = {<br/> FUNC: callback, <br/> scope: Scope <br/> }; <br/> If (method. tolowercase () = "get") {<br/> // Add a timestamp to prevent the browser from caching page data <br/> URL + = (URL. indexof ("? ")> 0? "&":"? ") <Br/> +" timestamp = "<br/> + new date (). gettime (); <br/>}< br/> // send a request <br/> request. open (method, URL, isasync); <br/> request. setRequestHeader (<br/> "Content-Type", <br/> (method. tolowercase () = "Post" <br/>? "Application/X-WWW-form-urlencoded;" <br/>: "text/XML") <br/>); <br/> If (ajaxconnectionpool. getbrowsertype ()! = "Firefox") {<br/> request. onreadystatechange = xmlcallbackhandler; <br/>}< br/> request. send (data); <br/> If (ajaxconnectionpool. getbrowsertype () = "Firefox") {<br/> // early call mode: request. onreadystatechange = xmlcallbackhandler (); <br/> request. onreadystatechange = xmlcallbackhandler; <br/>}< br/>}else {<br/> // when all requests are busy, the task is included in the waiting queue. <br/> var task ={< br/> method: method, <br/> URL: URL, <br/> data: data, <br/> callback: callback, <br/> scope: Scope <br/>}; <br/> taskqueue. push (task); <br/>}< br/>}; <br/> }();

 

2. Usage

 

// Obtain the idle request object <br/> var request = ajaxconnectionpool. getidlerequest (); </P> <p> // send data and use an asynchronous callback handler <br/> ajaxconnectionpool. send (method, URL, null, function () {<br/> // callback function processing logic <br/>}, window, true );

 

By codingmouse

2010.4.13