mvc5 源码解析2-2 mvchandler的执行

我们从application获取的时候查看stepmanager的实现类

IHttpHandler applicationInstance = HttpApplicationFactory.GetApplicationInstance(httpContext);

/ System.Web.HttpApplicationFactory
internal static IHttpHandler GetApplicationInstance(HttpContext context)
{
    if (HttpApplicationFactory._customApplication != null)
    {
        return HttpApplicationFactory._customApplication;
    }
    if (context.Request.IsDebuggingRequest)
    {
        return new HttpDebugHandler();
    }
    HttpApplicationFactory._theApplicationFactory.EnsureInited();
    HttpApplicationFactory._theApplicationFactory.EnsureAppStartCalled(context);
    return HttpApplicationFactory._theApplicationFactory.GetNormalApplicationInstance(context);
}

/ System.Web.HttpApplicationFactory
private HttpApplication GetNormalApplicationInstance(HttpContext context)
{
    HttpApplication httpApplication = null;
    if (!this._freeList.TryTake(out httpApplication))
    {
　　　　//创建application
        httpApplication = (HttpApplication)HttpRuntime.CreateNonPublicInstance(this._theApplicationType);
        using (new ApplicationImpersonationContext())
        {
　　　　　　　　//初始化application
            httpApplication.InitInternal(context, this._state, this._eventHandlerMethods);
        }
    }
    if (AppSettings.UseTaskFriendlySynchronizationContext)
    {
        httpApplication.ApplicationInstanceConsumersCounter = new CountdownTask();
        Task arg_8A_0 = httpApplication.ApplicationInstanceConsumersCounter.Task;
        Action<Task, object> arg_8A_1;
        if ((arg_8A_1 = HttpApplicationFactory.<>c.<>9__34_0) == null)
        {
            arg_8A_1 = (HttpApplicationFactory.<>c.<>9__34_0 = new Action<Task, object>(HttpApplicationFactory.<>c.<>.<GetNormalApplicationInstance>b__34_0));
        }
        arg_8A_0.ContinueWith(arg_8A_1, httpApplication, TaskContinuationOptions.ExecuteSynchronously);
    }
    return httpApplication;
}

初始化application

// System.Web.HttpApplication
internal void InitInternal(HttpContext context, HttpApplicationState state, MethodInfo[] handlers)
{
    this._state = state;
    PerfCounters.IncrementCounter(AppPerfCounter.PIPELINES);
    try
    {
        try
        {
            this._initContext = context;
            this._initContext.ApplicationInstance = this;
            context.ConfigurationPath = context.Request.ApplicationPathObject;
            using (new DisposableHttpContextWrapper(context))
            {
                if (HttpRuntime.UseIntegratedPipeline)
                {
                    try
                    {
                        context.HideRequestResponse = true;
                        this._hideRequestResponse = true;
                        this.InitIntegratedModules();
                        goto IL_6B;
                    }
                    finally
                    {
                        context.HideRequestResponse = false;
                        this._hideRequestResponse = false;
                    }
                }
                this.InitModules();
                IL_6B:
                if (handlers != null)
                {
                    this.HookupEventHandlersForApplicationAndModules(handlers);
                }
                this._context = context;
                if (HttpRuntime.UseIntegratedPipeline && this._context != null)
                {
                    this._context.HideRequestResponse = true;
                }
                this._hideRequestResponse = true;
                try
                {
                    this.Init();
                }
                catch (Exception error)
                {
                    this.RecordError(error);
                }
            }
            if (HttpRuntime.UseIntegratedPipeline && this._context != null)
            {
                this._context.HideRequestResponse = false;
            }
            this._hideRequestResponse = false;
            this._context = null;
            this._resumeStepsWaitCallback = new WaitCallback(this.ResumeStepsWaitCallback);
　　　　　　　　//判断是集成模式还是经典模式分别初始化不同的stepmanager
            if (HttpRuntime.UseIntegratedPipeline)
            {
                this._stepManager = new HttpApplication.PipelineStepManager(this);
            }
            else
            {
                this._stepManager = new HttpApplication.ApplicationStepManager(this);
            }
　　　　　　　　//创建步骤
            this._stepManager.BuildSteps(this._resumeStepsWaitCallback);
        }
        finally
        {
            this._initInternalCompleted = true;
            context.ConfigurationPath = null;
            this._initContext.ApplicationInstance = null;
            this._initContext = null;
        }
    }
    catch
    {
        throw;
    }
}

创建步骤及执行步骤

经典模式PipelineStepManager管道创建步骤

internal override void BuildSteps(WaitCallback stepCallback)
    {
　　　　//加入步骤各个事件
        ArrayList arrayList = new ArrayList();
        HttpApplication application = this._application;
        UrlMappingsSection urlMappings = RuntimeConfig.GetConfig().UrlMappings;
        bool flag = urlMappings.IsEnabled && urlMappings.UrlMappings.Count > ;
        arrayList.Add(new HttpApplication.ValidateRequestExecutionStep(application));
        arrayList.Add(new HttpApplication.ValidatePathExecutionStep(application));
        if (flag)
        {
            arrayList.Add(new HttpApplication.UrlMappingsExecutionStep(application));
        }
        application.CreateEventExecutionSteps(HttpApplication.EventBeginRequest, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventAuthenticateRequest, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventDefaultAuthentication, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventPostAuthenticateRequest, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventAuthorizeRequest, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventPostAuthorizeRequest, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventResolveRequestCache, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventPostResolveRequestCache, arrayList);
　　　
        arrayList.Add(new HttpApplication.MapHandlerExecutionStep(application));
        application.CreateEventExecutionSteps(HttpApplication.EventPostMapRequestHandler, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventAcquireRequestState, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventPostAcquireRequestState, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventPreRequestHandlerExecute, arrayList);
        arrayList.Add(application.CreateImplicitAsyncPreloadExecutionStep());
　　　　//加入mvchandler执行的步骤事件
        arrayList.Add(new HttpApplication.CallHandlerExecutionStep(application));
        application.CreateEventExecutionSteps(HttpApplication.EventPostRequestHandlerExecute, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventReleaseRequestState, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventPostReleaseRequestState, arrayList);
        arrayList.Add(new HttpApplication.CallFilterExecutionStep(application));
        application.CreateEventExecutionSteps(HttpApplication.EventUpdateRequestCache, arrayList);
        application.CreateEventExecutionSteps(HttpApplication.EventPostUpdateRequestCache, arrayList);
        this._endRequestStepIndex = arrayList.Count;
        application.CreateEventExecutionSteps(HttpApplication.EventEndRequest, arrayList);
        arrayList.Add(new HttpApplication.NoopExecutionStep());
        this._execSteps = new HttpApplication.IExecutionStep[arrayList.Count];
        arrayList.CopyTo(this._execSteps);
        this._resumeStepsWaitCallback = stepCallback;
    }

CallHandlerExecutionStep

void HttpApplication.IExecutionStep.Execute()
    {
        HttpContext context = this._application.Context;
        IHttpHandler handler = context.Handler;
        if (EtwTrace.IsTraceEnabled(4, 4))
        {
            EtwTrace.Trace(EtwTraceType.ETW_TYPE_HTTPHANDLER_ENTER, context.WorkerRequest);
        }
        if (handler != null && HttpRuntime.UseIntegratedPipeline)
        {
            IIS7WorkerRequest iIS7WorkerRequest = context.WorkerRequest as IIS7WorkerRequest;
            if (iIS7WorkerRequest != null && iIS7WorkerRequest.IsHandlerExecutionDenied())
            {
                this._sync = true;
                HttpException ex = new HttpException(403, SR.GetString("Handler_access_denied"));
                ex.SetFormatter(new PageForbiddenErrorFormatter(context.Request.Path, SR.GetString("Handler_access_denied")));
                throw ex;
            }
        }
        if (handler == null)
        {
            this._sync = true;
            return;
        }
        if (handler is IHttpAsyncHandler)
        {
            IHttpAsyncHandler httpAsyncHandler = (IHttpAsyncHandler)handler;
            this._sync = false;
            this._handler = httpAsyncHandler;
            Func<HttpContext, AsyncCallback, object, IAsyncResult> func = AppVerifier.WrapBeginMethod<HttpContext>(this._application, new Func<HttpContext, AsyncCallback, object, IAsyncResult>(httpAsyncHandler.BeginProcessRequest));
            this._asyncStepCompletionInfo.Reset();
            context.SyncContext.AllowVoidAsyncOperations();
            IAsyncResult asyncResult;
            try
            {
　　　　　　　　　　//执行beginprocessrequest方法
                asyncResult = func(context, this._completionCallback, null);
            }
            catch
            {
                context.SyncContext.ProhibitVoidAsyncOperations();
                throw;
            }
            bool flag;
            bool flag2;
            this._asyncStepCompletionInfo.RegisterBeginUnwound(asyncResult, out flag, out flag2);
            if (flag)
            {
                this._sync = true;
                this._handler = null;
                context.SyncContext.ProhibitVoidAsyncOperations();
                try
                {
                    if (flag2)
                    {
                        httpAsyncHandler.EndProcessRequest(asyncResult);
                    }
                    this._asyncStepCompletionInfo.ReportError();
                }
                finally
                {
                    HttpApplication.CallHandlerExecutionStep.SuppressPostEndRequestIfNecessary(context);
                    context.Response.GenerateResponseHeadersForHandler();
                }
                if (EtwTrace.IsTraceEnabled(4, 4))
                {
                    EtwTrace.Trace(EtwTraceType.ETW_TYPE_HTTPHANDLER_LEAVE, context.WorkerRequest);
                    return;
                }
            }
        }
        else
        {
            this._sync = true;
            context.SyncContext.SetSyncCaller();
            try
            {
                handler.ProcessRequest(context);
            }
            finally
            {
                context.SyncContext.ResetSyncCaller();
                if (EtwTrace.IsTraceEnabled(4, 4))
                {
                    EtwTrace.Trace(EtwTraceType.ETW_TYPE_HTTPHANDLER_LEAVE, context.WorkerRequest);
                }
                HttpApplication.CallHandlerExecutionStep.SuppressPostEndRequestIfNecessary(context);
                context.Response.GenerateResponseHeadersForHandler();
            }
        }
    }

执行步骤

internal override void ResumeSteps(Exception error)
    {
        bool flag = false;
        bool flag2 = true;
        HttpApplication application = this._application;
        CountdownTask applicationInstanceConsumersCounter = application.ApplicationInstanceConsumersCounter;
        HttpContext context = application.Context;
        ThreadContext threadContext = null;
        AspNetSynchronizationContextBase syncContext = context.SyncContext;
        try
        {
            if (applicationInstanceConsumersCounter != null)
            {
                applicationInstanceConsumersCounter.MarkOperationPending();
            }
            using (syncContext.AcquireThreadLock())
            {
                try
                {
                    threadContext = application.OnThreadEnter();
                }
                catch (Exception ex)
                {
                    if (error == null)
                    {
                        error = ex;
                    }
                }
                try
                {
                    try
                    {
                        while (true)
                        {
                            if (syncContext.Error != null)
                            {
                                error = syncContext.Error;
                                syncContext.ClearError();
                            }
                            if (error != null)
                            {
                                application.RecordError(error);
                                error = null;
                            }
                            if (syncContext.PendingCompletion(this._resumeStepsWaitCallback))
                            {
                                goto IL_123;
                            }
                            if (this._currentStepIndex < this._endRequestStepIndex && (context.Error != null || this._requestCompleted))
                            {
                                context.Response.FilterOutput();
                                this._currentStepIndex = this._endRequestStepIndex;
                            }
                            else
                            {
                                this._currentStepIndex++;
                            }
                            if (this._currentStepIndex >= this._execSteps.Length)
                            {
                                break;
                            }
                            this._numStepCalls++;
                            syncContext.Enable();
　　　　　　　　　　　　　　　　　　//执行每个事件中的Excute方法
                            error = application.ExecuteStep(this._execSteps[this._currentStepIndex], ref flag2);
                            if (!flag2)
                            {
                                goto IL_123;
                            }
                            this._numSyncStepCalls++;
                        }
                        flag = true;
                        IL_123:;
                    }
                    finally
                    {
                        if (flag)
                        {
                            context.RaiseOnRequestCompleted();
                        }
                        if (threadContext != null)
                        {
                            try
                            {
                                threadContext.DisassociateFromCurrentThread();
                            }
                            catch
                            {
                            }
                        }
                    }
                }
                catch
                {
                    throw;
                }
            }
            if (flag)
            {
                context.RaiseOnPipelineCompleted();
                context.Unroot();
                application.AsyncResult.Complete(this._numStepCalls == this._numSyncStepCalls, null, null);
                application.ReleaseAppInstance();
            }
        }
        finally
        {
            if (applicationInstanceConsumersCounter != null)
            {
                applicationInstanceConsumersCounter.MarkOperationCompleted();
            }
        }
    }

集成模式同理