AjaxPro实现机制浅析.doc

AjaxPro实现机制浅析以一个最简单的例子开始：点击一个客户端button，触发一个javascript函数，执行一个只有一个string参数的服务端方法，返回一个处理过的string，处理方法是将传入的string变成“Hi”+string +“！”；够简单了，为了是不希望罗嗦的代码影响简单的分析；所有代码如下：无标题页functiondoTest()AJAXDemo.Examples.Test.TestMethod.GetTest(AjaxPro,doTest_callback);functiondoTest_callback(res)alert(res.value);Test.aspx.cspublicpartialclassTest:System.Web.UI.PageprotectedvoidPage_Load(objectsender,EventArgse)Utility.RegisterTypeForAjax(typeof(AJAXDemo.Examples.Test.TestMethod);AJAXDemo.Examples.TestusingSystem;usingAjaxPro;namespaceAJAXDemo.Examples.TestpublicclassTestMethodpublicTestMethod()AjaxMethodpublicstringGetTest(stringtestText)returnHi,+testText+!;1.首先我们看AjaxPro在页面上给我们生成了什么？Test1无标题页functiondoTest()AJAXDemo.Examples.Test.TestMethod.GetTest(AjaxPro,doTest_callback);functiondoTest_callback(res)alert(res.value);一定要注意这几行通过使用http:/localhost:3578/AJAXDemo.2/ajaxpro/prototype.ashx和http:/localhost:3578/AJAXDemo.2/ajaxpro/core.ashx不难发现，其中前面两个是源代码中带的两个js文件（core.js和prototype.js）转化出来的，基本内容也跟原来的文件一样，而converter.ashx和AJAXDemo.Examples.Test.TestMethod,App_Code.urx4hqkg.ashx里面有什么呢？看下面：AJAXDemo.Examples.Test.TestMethod,App_Code.urx4hqkg.ashxaddNamespace(AJAXDemo.Examples.Test);AJAXDemo.Examples.Test.TestMethod_class=Class.create();AJAXDemo.Examples.Test.TestMethod_totype=(newAjaxPro.AjaxClass().extend(GetTest:function(testText)returnthis.invoke(GetTest,testText:testText,this.GetTest.getArguments().slice(1);,initialize:function()this.url=/AJAXDemo.2/ajaxpro/AJAXDemo.Examples.Test.TestMethod,App_Code.un7rskvh.ashx;);AJAXDemo.Examples.Test.TestMethod=newAJAXDemo.Examples.Test.TestMethod_class();converter.ashx addNamespace(Ajax.Web);Ajax.Web.NameValueCollection=function()this._type=System.Collections.Specialized.NameValueCollection;this.add=function(key,value)if(thiskey=null)thiskey=value;this.getKeys=function()varkeys=;for(keyinthis)if(typeofthiskey!=function)keys.push(key);returnkeys;this.getValue=function(key)returnthiskey;this.toJSON=function()varo=this;o.toJSON=null;deleteo.toJSON;returnAjaxPro.toJSON(o);addNamespace(Ajax.Web);Ajax.Web.DataTable=function(columns,rows)this._type=System.Data.DataTable,System.Data;this.Columns=newArray();this.Rows=newArray();this.addColumn=function(name,type)varc=newObject();c.Name=name;c._type=type;this.Columns.push(c);this.toJSON=function()vardt=newObject();dt.Columns=;for(vari=0;ithis.Columns.length;i+)dt.Columns.push(this.Columnsi.Name,this.Columnsi._type);dt.Rows=;for(vari=0;ithis.Rows.length;i+)varrow=;for(varj=0;jthis.Columns.length;j+)row.push(this.Rowsithis.Columnsj.Name);dt.Rows.push(row);returnAjaxPro.toJSON(dt);this.addRow=function(row)this.Rows.push(row);if(columns!=null)for(vari=0;icolumns.length;i+)this.addColumn(columnsi0,columnsi1);if(rows!=null)for(vari=0;irows.length;i+)varrow=newObject();for(varc=0;cthis.Columns.length&crowsi.length;c+)rowthis.Columnsc.Name=rowsic;this.addRow(row);addNamespace(Ajax.Web);Ajax.Web.DataSet=function(tables)this._type=System.Data.DataSet,System.Data;this.Tables=newArray();this.addTable=function(table)this.Tables.push(table);if(tables!=null)for(vari=0;itables.length;i+)this.addTable(tablesi);functionPerson(id)this.FirstName=;this.FamilyName=;this.Age=0;this.ID=id;this._type=AJAXDemo.Examples.Classes.Person,App_Code.un7rskvh,Version=,Culture=neutral,PublicKeyToken=null;Ptotype.get_FullName=function()returnthis.FirstName+this.FamilyName;Ptotype.toJSON=function()varo=newObject();o.firstName=this.FirstName;o.familyName=this.FamilyName;o.age=this.Age;o.id=this.ID;returnAjaxPro.toJSON(o);Ptotype.save=function()returnPerson.save(this);Person.save=function(p)varps=newPersonSaver();returnps.savePerson(p);/synchronouscallvarPersonSaver=Class.create();PersonStotype=(newAjaxPro.Request().extend(savePerson:function(p)returnthis.invoke(SavePerson,p:p).value;,initialize:function()this.url=ajaxpro/AJAXDemo.Examples.Classes.Person,App_Code.un7rskvh,Version=,Culture=neutral,PublicKeyToken=null.ashx;)正因为是有了上面四个ashx文件我们的functiondoTest() AJAXDemo.Examples.Test.TestMethod.GetTest(AjaxPro,doTest_callback);才得以异步执行，这些ashx文件又是怎么生成到页面上的，那得归功于web.config的相关配置和下面这句代码：Utility.RegisterTypeForAjax(typeof(AJAXDemo.Examples.Test.TestMethod);至于Utility.RegisterTypeForAjax方法产生的一序列动作我将在后文中继续说明，有兴趣的可以自己跟踪下这些代码的执行。说到AjaxPro为我们生成了四个ashx文件来达到异步调用的目的，这次呢，就说说这些ashx文件是怎么生成的；核心部分是其web.config配置了httpHandlers 元素作用是：对ajaxpro目录下的*.ashx文件的POST,GET请求交由程序集AjaxPro下的AjaxPro.AjaxHandlerFactory类来处理；ps:关于httpHandlers的说明可以参看下面几个连接1.httpHandlers 元素（ASP.NET 设置架构）2.Microsoft ASP.NET 快速入门教程3.ASP.NET中的Http Handles 先看看实现IHttpHandlerFactory接口的AjaxHandlerFactory类，只实现了GetHandler方法其中对core，prototype的处理没什么可说，只是简单的通过EmbeddedJavaScriptHandler的ProcessRequest中将js写入.ashx文件，而converter比较复杂留代下次再做详细分析；这里就重点看看AJAXDemo.Examples.Test.TestMethod,App_Code.urx4hqkg.ashx是怎么来的了；我跟踪了下代码的运行，在页面加载的时候自定义 HttpHandler 启用 HTTP Web 请求的处理ProcessRequest，也就是进入AjaxHandlerFactory类GetHandler方法的如下入口default:if(Utility.Settings.UrlNamespaceMappings.Contains(filename)t=Type.GetType(Utility.Settings.UrlNamespaceMappingsfilename.ToString();if(t=null)t=Type.GetType(filename);returnnewTypeJavaScriptHandler(t);TypeJavaScriptHandler也实现了IHttpHandler接口，其ProcessRequest方法如下：publicvoidProcessRequest(HttpContextcontext)/Therequestwasnotarequesttoinvokeaserver-sidemethod./Now,wewillrendertheJavascriptthatwillbeusedonthe/clienttorunasaproxyorwrapperforthemethodsmarked/withtheAjaxMethodAttribute.if(context.Trace.IsEnabled)context.Trace.Write(Constant.AjaxID,RenderclassproxyJavascript);System.Reflection.MethodInfomi=type.GetMethods();/Checkwetherthejavascriptisalreadyrenderedandcachedinthe/currentcontext.stringetag=context.Request.HeadersIf-None-Match;stringmodSince=context.Request.HeadersIf-Modified-Since;stringpath=type.FullName+,+type.Assembly.FullName.Split(,)0;if(Utility.Settings!=null&Utility.Settings.UrlNamespaceMappings.ContainsValue(path)foreach(stringkeyinUtility.Settings.UrlNamespaceMappings.Keys)if(Utility.Settings.UrlNamespaceMappingskey.ToString()=path)path=key;break;if(context.Cachepath!=null)CacheInfoci=(CacheInfo)context.Cachepath;if(etag!=null)if(etag=ci.ETag)/TODO:nullcheckcontext.Response.StatusCode=304;return;if(modSince!=null)tryDateTimemodSinced=Convert.ToDateTime(modSince.ToString().ToUniversalTime();if(DateTime.Compare(modSinced,ci.LastModified.ToUniversalTime()=0)context.Response.StatusCode=304;return;catch(Exception)if(context.Trace.IsEnabled)context.Trace.Write(Constant.AjaxID,TheheadervalueforIf-Modified-Since=+modSince+couldnotbeconvertedtoaSystem.DateTime.);etag=type.AssemblyQualifiedName;/+_+type.Assembly.DateTime.Now.ToString(System.Globalization.DateTimeFormatInfo.CurrentInfo.SortableDateTimePattern);etag=MD5Helper.GetHash(System.Text.Encoding.Default.GetBytes(etag);DateTimenow=DateTime.Now;DateTimelastMod=newDateTime(now.Year,now.Month,now.Day,now.Hour,now.Minute,now.Second);/.ToUniversalTime();context.Response.AddHeader(Content-Type,application/x-javascript);context.Response.ContentEncoding=System.Text.Encoding.UTF8;context.Response.Cache.SetCacheability(System.Web.HttpCacheability.Public);context.Response.Cache.SetETag(etag);context.Response.Cache.SetLastModified(lastMod);/Ok,wedonothavethejavascriptrendered,yet./Buildthejavascriptsourceandsaveittothecurrent/Applicationcontext.System.Text.StringBuildersb=newSystem.Text.StringBuilder();AjaxNamespaceAttributecma=(AjaxNamespaceAttribute)type.GetCustomAttributes(typeof(AjaxNamespaceAttribute),true);stringclientNS=type.FullName;if(cma.Length0&cma0.ClientNamespace!=null)if(cma0.ClientNamespace.IndexOf(.)0)sb.Append(addNamespace(+cma0.ClientNamespace+);rn);clientNS=cma0.ClientNamespace;elsesb.Append(addNamespace(+(type.FullName.IndexOf(.)0?type.FullName.Substring(0,type.FullName.LastIndexOf(.):type.FullName)+);rn);sb.Append(clientNS);sb.Append(_class=Class.create();rn);sb.Append(clientNS);sb.Append(_totype=(newAjaxPro.AjaxClass().extend(rn);System.Reflection.MethodInfomethod;for(inty=0;ymi.Length;y+)method=miy;if(!method.IsPublic)continue;AjaxNamespaceAttributecmam=(AjaxNamespaceAttribute)method.GetCustomAttributes(typeof(AjaxNamespaceAttribute),true);AjaxMethodAttributema=(AjaxMethodAttribute)method.GetCustomAttributes(typeof(AjaxMethodAttribute),true);if(ma.Length=0)continue;System.Reflection.ParameterInfopi=method.GetParameters();/Renderthefunctionheadersb.Append(t);if(cmam.Length=0)sb.Append(method.Name);elsesb.Append(cmam0.ClientNamespace);sb.Append(:function();/Renderallparametersfor(inti=0;ipi.Length;i+)sb.Append(pii.Name);if(ipi.Length-1)sb.Append(,);sb.Append()rn);/CreatetheXMLHttpRequestobjectsb.Append(ttreturnthis.invoke(+method.Name+,);/mustbetheoriginalmethodnamefor(inti=0;ipi.Length;i+)sb.Append();sb.Append(pii.Name);sb.Append(:);sb.Append(pii.Name);if(ipi.Length-1)sb.Append(,);sb.Append(,this.);if(cmam.Length=0)sb.Append(method.Name);elsesb.Append(cmam0.ClientNamespace);sb.Append(.getArguments().slic