知识大全 Asp.Net页面执行流程分析

Posted 2022-07-17 知

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　　在我的上一篇文章中说到了HttpModule HttpHandle的简单使用我们可以利用它们在页面请求的过程中加入自己的事件处理程序那么在一个aspx页面请求时后台到底做了什么？当然做了很多事情过程也比较复杂本文主要分析一下大体的流程总体流程如下请求一个页面时首先被WWW服务截获(inetinfo exe进程) 这个进程首先判断页面的后缀然后根据IIS中的配置来决定调用哪个扩展程序比如aspx的页面就会调用c:\\windows\\\\framework\\v \\aspnet_isapi dll aspnet_isapi dll将请求发送给w wp exe进程(我们在调试IIS中网站时就是把VS 附加到这个进程上的) 接下来w wp exe进程就会调类库进行具体处理 ISAPIRuntime >HttpRuntime >HttpApplicationFactory >HttpApplication >HttpModule HttpHandlerFactory >HttpHandler 这也是本文主要分析的地方

　　下面只是列出主要流程如果喜欢钻研的同学可以用Reflector去查看一 ISAPIRuntime bool useOOP = iWRType == ; wr = ISAPIWorkerRequest CreateWorkerRequest(ecb useOOP); wr Initialize(); string appPathTranslated = wr GetAppPathTranslated(); string appDomainAppPathInternal = HttpRuntime AppDomainAppPathInternal; if ((appDomainAppPathInternal == null) || StringUtil EqualsIgnoreCase(appPathTranslated appDomainAppPathInternal)) HttpRuntime ProcessRequestNoDemand(wr); return ; HttpRuntime ShutdownAppDomain(ApplicationShutdownReason PhysicalApplicationPathChanged SR GetString( Hosting_Phys_Path_Changed new object[] appDomainAppPathInternal appPathTranslated )); return ;它的主要作用是调用一些非托管代码生成HttpWorkerRequest对象该对象包含当前请求的所有信息然后传递给HttpRuntime 这里生成的HttpWorkerRequest对象可以直接在我们的页面中调用的通过它取得原始的请求信息 IServiceProvider provider = (IServiceProvider)HttpContext Current; HttpWorkerRequest wr = (HttpWorkerRequest)provider GetService(typeof(HttpWorkerRequest));

　　二 HttpRuntime最主要的就是private void ProcessRequestInternal(HttpWorkerRequest wr)方法 context = new HttpContext(wr false);

　　IHttpHandler applicationInstance = HttpApplicationFactory GetApplicationInstance(context);

　　IHttpAsyncHandler handler = (IHttpAsyncHandler) applicationInstance; context AsyncAppHandler = handler ; handler BeginProcessRequest(context this _handlerCompletionCallback context); 根据HttpWorkerRequest对象生成HttpContext HttpContext应该大家都很熟悉的它包含request response等属性在页面中经常会用到的调用HttpApplicationFactory来生成IHttpHandler(这里生成的是一个默认的HttpApplication对象 HttpApplication也是IHttpHandler接口的一个实现) 调用HttpApplication对象执行请求三 HttpApplicationFactory正如中所提到的这里主要是生成一个HttpApplication对象

　　internal static string GetApplicationFile() return Path Combine(HttpRuntime AppDomainAppPathInternal global asax ); 首先会查看是否存在global asax文件如果有的话就用它来生成HttpApplication对象从这里我们可以看到global asax的文件名是在的框架中写死的不能修改的如果这个文件不存在就使用默认的对象创建好HttpApplication之后对它进行初始化 application = (HttpApplication) HttpRuntime CreateNonPublicInstance(this _theApplicationType); using (ApplicationImpersonationContext context = new ApplicationImpersonationContext()) application InitInternal(context this _state this _eventHandlerMethods); 四 HttpApplication这个是比较复杂也比较重要的一个对象首先是执行初始化操作比较重要的一步就是进行HttpModule的初始化 private void InitModules() this _moduleCollection = RuntimeConfig GetAppConfig() HttpModules CreateModules(); this InitModulesCommon(); 它会读取nfig中所有HttpModule的配置在HookupEventHandlersForApplicationAndModules方法中绑定Module的事件处理程序接着进行事件实际绑定 if (HttpRuntime UseIntegratedPipeline) this _stepManager = new PipelineStepManager(this); else this _stepManager = new ApplicationStepManager(this); this _stepManager BuildSteps(this _resumeStepsWaitCallback);在ApplicationStepManager的BuildSteps方法中可以看到事件的绑定执行顺序

　　app CreateEventExecutionSteps(HttpApplication EventBeginRequest steps); app CreateEventExecutionSteps(HttpApplication EventAuthenticateRequest steps); app CreateEventExecutionSteps(HttpApplication EventDefaultAuthentication steps); app CreateEventExecutionSteps(HttpApplication EventPostAuthenticateRequest steps); app CreateEventExecutionSteps(HttpApplication EventAuthorizeRequest steps); app CreateEventExecutionSteps(HttpApplication EventPostAuthorizeRequest steps); app CreateEventExecutionSteps(HttpApplication EventResolveRequestCache steps); app CreateEventExecutionSteps(HttpApplication EventPostResolveRequestCache steps); steps Add(new HttpApplication MapHandlerExecutionStep(app)); app CreateEventExecutionSteps(HttpApplication EventPostMapRequestHandler steps); app CreateEventExecutionSteps(HttpApplication EventAcquireRequestState steps); app CreateEventExecutionSteps(HttpApplication EventPostAcquireRequestState steps); app CreateEventExecutionSteps(HttpApplication EventPreRequestHandlerExecute steps); steps Add(new HttpApplication CallHandlerExecutionStep(app)); app CreateEventExecutionSteps(HttpApplication EventPostRequestHandlerExecute steps); app CreateEventExecutionSteps(HttpApplication EventReleaseRequestState steps); app CreateEventExecutionSteps(HttpApplication EventPostReleaseRequestState steps); steps Add(new HttpApplication CallFilterExecutionStep(app)); app CreateEventExecutionSteps(HttpApplication EventUpdateRequestCache steps); app CreateEventExecutionSteps(HttpApplication EventPostUpdateRequestCache steps); this _endRequestStepIndex = steps Count; app CreateEventExecutionSteps(HttpApplication EventEndRequest steps); steps Add(new HttpApplication NoopExecutionStep());注意上面红色标注的MapHandlerExecutionStep(读取所有的HttpHandler配置) CallHandlerExecutionStep就是对Handle程序进行处理的也就是说在nfig中配置的HttpHandler都是在这里进行处理的执行顺序如上所示

　　然后就是调用中的方法执行请求 Code IAsyncResult IHttpAsyncHandler BeginProcessRequest(HttpContext context AsyncCallback cb object extraData) this _context = context; this _context ApplicationInstance = this; this _stepManager InitRequest(); this _context Root(); HttpAsyncResult result = new HttpAsyncResult(cb extraData); this AsyncResult = result; if (this _context TraceIsEnabled) HttpRuntime Profile StartRequest(this _context); this ResumeSteps(null); return result; 在ResumeSteps中就是执行事件处理程序

　　五 HttpModule在系统nfig中默认的配置有 Code <Modules> <add name= OutputCache type= System Web Caching OutputCacheModule /> <add name= Session type= System Web SessionState SessionStateModule /> <add name= WindowsAuthentication type= System Web Security WindowsAuthenticationModule /> <add name= FormsAuthentication type= System Web Security FormsAuthenticationModule /> <add name= PassportAuthentication type= System Web Security PassportAuthenticationModule /> <add name= RoleManager type= System Web Security RoleManagerModule /> <add name= UrlAuthorization type= System Web Security UrlAuthorizationModule /> <add name= FileAuthorization type= System Web Security FileAuthorizationModule /> <add name= AnonymousIdentification type= System Web Security AnonymousIdentificationModule /> <add name= Profile type= System Web Profile ProfileModule /> <add name= ErrorHandlerModule type= System Web Mobile ErrorHandlerModule System Web Mobile Version= Culture=neutral PublicKeyToken=b f f f d a a /> <add name= ServiceModel type= System ServiceModel Activation HttpModule System ServiceModel Version= Culture=neutral PublicKeyToken=b a c e /> </Modules>基本使用方法可以参见我的上一篇文章

　　六 HttpHandlerFactory HttpHandler这两个对象在nfig中的配置方法是相同的默认配置有 Code <add path= * rules verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * xoml verb= * type= System ServiceModel Activation HttpHandler System ServiceModel Version= Culture=neutral PublicKeyToken=b a c e validate= false /> <add path= trace axd verb= * type= System Web Handlers TraceHandler validate= true /> <add path= WebResource axd verb= GET type= System Web Handlers AssemblyResourceLoader validate= true /> <add path= * axd verb= * type= System Web HttpNotFoundHandler validate= true /> <add path= * aspx verb= * type= System Web UI PageHandlerFactory validate= true /> <add path= * ashx verb= * type= System Web UI SimpleHandlerFactory validate= true /> <add path= * asmx verb= * type= System Web Services Protocols WebServiceHandlerFactory System Web Services Version= Culture=neutral PublicKeyToken=b f f f d a a validate= false /> <add path= * rem verb= * type= System Runtime Remoting Channels Http HttpRemotingHandlerFactory System Runtime Remoting Version= Culture=neutral PublicKeyToken=b a c e validate= false /> <add path= * soap verb= * type= System Runtime Remoting Channels Http HttpRemotingHandlerFactory System Runtime Remoting Version= Culture=neutral PublicKeyToken=b a c e validate= false /> <add path= * asax verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * ascx verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * master verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * skin verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * browser verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * sitemap verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= *nfig verb= GET HEAD type= System Web StaticFileHandler validate= true /> <add path= *nfig verb= GET HEAD type= System Web StaticFileHandler validate= true /> <add path= nfig verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * cs verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * csproj verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * vb verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * vbproj verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * webinfo verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * licx verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * resx verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * resources verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * mdb verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * vjsproj verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * java verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * jsl verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * ldb verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * ad verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * dd verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * ldd verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * sd verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * cd verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * adprototype verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * lddprototype verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * sdm verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * sdmDocument verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * mdf verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * ldf verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * exclude verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * refresh verb= * type= System Web HttpForbiddenHandler validate= true /> <add path= * svc verb= * type= System ServiceModel Activation HttpHandler System ServiceModel Version= Culture=neutral PublicKeyToken=b a c e validate= false /> <add path= * verb= GET HEAD POST type= System Web DefaultHttpHandler validate= true /> <add path= * verb= * type= System Web HttpMethodNotAllowedHandler validate= true /> </Handlers>要注意的是相同的后缀名配置多次的话后面的配置会把前面的覆蓋

　　这里我们重点看一下aspx的配置 System Web UI PageHandlerFactory这是一个HttpHandlerFactory对象根据不同的Page生成不同的HttpHandler对象(我们自己的Page页面都是一个IHttpHandler) Page page = BuildManager CreateInstanceFromVirtualPath(virtualPath typeof(Page) context true true) as Page; if (page == null) return null; page TemplateControlVirtualPath = virtualPath; return page;这里会调用nfig中的buildProviders配置编译页面 Code<buildProviders> <add extension= aspx type= System Web Compilation PageBuildProvider /> <add extension= ascx type= System Web Compilation UserControlBuildProvider /> <add extension= master type= System Web Compilation MasterPageBuildProvider /> <add extension= asmx type= System Web Compilation WebServiceBuildProvider /> <add extension= ashx type= System Web Compilation WebHandlerBuildProvider /> <add extension= soap type= System Web Compilation WebServiceBuildProvider /> <add extension= resx type= System Web Compilation ResXBuildProvider /> <add extension= resources type= System Web Compilation ResourcesBuildProvider /> <add extension= wsdl type= System Web Compilation WsdlBuildProvider /> <add extension= xsd type= System Web Compilation XsdBuildProvider /> <add extension= js type= System Web Compilation ForceCopyBuildProvider /> <add extension= lic type= System Web Compilation IgnoreFileBuildProvider /> <add extension= licx type= System Web Compilation IgnoreFileBuildProvider /> <add extension= exclude type= System Web Compilation IgnoreFileBuildProvider /> <add extension= refresh type= System Web Compilation IgnoreFileBuildProvider /> <add extension= xoml type= System ServiceModel Activation WorkflowServiceBuildProvider System WorkflowServices Version= Culture=neutral PublicKeyToken= bf ad e /> <add extension= svc type= System ServiceModel Activation ServiceBuildProvider System ServiceModel Version= Culture=neutral PublicKeyToken=b a c e /> </buildProviders>

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