mvc5 源碼解析2-1：mvchandler的執行

時間 2019-12-05

標籤 mvc5 mvc 源碼解析 mvchandler 執行简体版

原文原文鏈接

上一節說在urlroutingmodule中mvchandler 映射到httpcontext上，那mvchandler又是怎麼執行的呢？html

（1）、httpruntimeapi

從isapiruntime pr方法到httpruntimemvc

ProcessRequestNoDemand(wr)方法app

// System.Web.HttpRuntime
internal static void ProcessRequestNoDemand(HttpWorkerRequest wr)
{
　　//獲取請求隊列
    RequestQueue requestQueue = HttpRuntime._theRuntime._requestQueue;
    wr.UpdateInitialCounters();
    if (requestQueue != null)
    {
        wr = requestQueue.GetRequestToExecute(wr);
    }
    if (wr != null)
    {
        HttpRuntime.CalculateWaitTimeAndUpdatePerfCounter(wr);
        wr.ResetStartTime();
        HttpRuntime.ProcessRequestNow(wr);
    }
}

ProcessRequestNow(wr)方法async

// System.Web.HttpRuntime
internal static void ProcessRequestNow(HttpWorkerRequest wr)
{
    HttpRuntime._theRuntime.ProcessRequestInternal(wr);
}

ProcessRequestInternal(wr)方法ui

// System.Web.HttpRuntime
private void ProcessRequestInternal(HttpWorkerRequest wr)
{
　　//活動請求數量增長
    Interlocked.Increment(ref this._activeRequestCount);
　　//判斷請求數異常
    if (this._disposingHttpRuntime)
    {
        try
        {
            wr.SendStatus(503, "Server Too Busy");
            wr.SendKnownResponseHeader(12, "text/html; charset=utf-8");
            byte[] bytes = Encoding.ASCII.GetBytes("<html><body>Server Too Busy</body></html>");
            wr.SendResponseFromMemory(bytes, bytes.Length);
            wr.FlushResponse(true);
            wr.EndOfRequest();
        }
        finally
        {
            Interlocked.Decrement(ref this._activeRequestCount);
        }
        return;
    }
    HttpContext httpContext;
    try
    {
　　　　　　//HttpWorkerRequest轉HttpContext
        httpContext = new HttpContext(wr, false);
    }
    catch
    {
        try
        {
            wr.SendStatus(400, "Bad Request");
            wr.SendKnownResponseHeader(12, "text/html; charset=utf-8");
            byte[] bytes2 = Encoding.ASCII.GetBytes("<html><body>Bad Request</body></html>");
            wr.SendResponseFromMemory(bytes2, bytes2.Length);
            wr.FlushResponse(true);
            wr.EndOfRequest();
            return;
        }
        finally
        {
            Interlocked.Decrement(ref this._activeRequestCount);
        }
    }
    wr.SetEndOfSendNotification(this._asyncEndOfSendCallback, httpContext);
    HostingEnvironment.IncrementBusyCount();
    try
    {
        try
        {
            this.EnsureFirstRequestInit(httpContext);
        }
        catch
        {
            if (!httpContext.Request.IsDebuggingRequest)
            {
                throw;
            }
        }
        httpContext.Response.InitResponseWriter();
　　　　//獲取application實例
        IHttpHandler applicationInstance = HttpApplicationFactory.GetApplicationInstance(httpContext);
        if (applicationInstance == null)
        {
            throw new HttpException(SR.GetString("Unable_create_app_object"));
        }
        if (EtwTrace.IsTraceEnabled(5, 1))
        {
            EtwTrace.Trace(EtwTraceType.ETW_TYPE_START_HANDLER, httpContext.WorkerRequest, applicationInstance.GetType().FullName, "Start");
        }
　　　　//判斷application實例是否有繼承IHttpAsyncHandler if (applicationInstance is IHttpAsyncHandler)
        {
            IHttpAsyncHandler httpAsyncHandler = (IHttpAsyncHandler)applicationInstance;
            httpContext.AsyncAppHandler = httpAsyncHandler;
　　　　　　　　//執行application的BeginProcessRequest
            httpAsyncHandler.BeginProcessRequest(httpContext, this._handlerCompletionCallback, httpContext);
        }
        else
        {
            applicationInstance.ProcessRequest(httpContext);
            this.FinishRequest(httpContext.WorkerRequest, httpContext, null);
        }
    }
    catch (Exception e)
    {
        httpContext.Response.InitResponseWriter();
        this.FinishRequest(wr, httpContext, e);
    }
}

BeginProcessRequest方法this

IAsyncResult IHttpAsyncHandler.BeginProcessRequest(HttpContext context, AsyncCallback cb, object extraData)
        {
            this._context = context;
            this._context.ApplicationInstance = this;
　　　　　　　　
            this._stepManager.InitRequest();
            this._context.Root();
            HttpAsyncResult httpAsyncResult = new HttpAsyncResult(cb, extraData);
            this.AsyncResult = httpAsyncResult;
            if (this._context.TraceIsEnabled)
            {
                HttpRuntime.Profile.StartRequest(this._context);
            }
　　　　　　　　//執行步驟
            this.ResumeSteps(null);
            return httpAsyncResult;
        }

ResumeSteps方法url

private void ResumeSteps(Exception error)
        {
            this._stepManager.ResumeSteps(error);
        }

this._stepManager 抽象類spa

internal abstract class StepManager
        {
            protected HttpApplication _application;

            protected bool _requestCompleted;

            internal bool IsCompleted
            {
                get
                {
                    return this._requestCompleted;
                }
            }

            internal StepManager(HttpApplication application)
            {
                this._application = application;
            }

            internal abstract void BuildSteps(WaitCallback stepCallback);

            internal void CompleteRequest()
            {
                this._requestCompleted = true;
                if (HttpRuntime.UseIntegratedPipeline)
                {
                    HttpContext context = this._application.Context;
                    if (context != null && context.NotificationContext != null)
                    {
                        context.NotificationContext.RequestCompleted = true;
                    }
                }
            }

            internal abstract void InitRequest();

            internal abstract void ResumeSteps(Exception error);
        }

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