Asp.net请求处理之管道处理介绍
2024-07-10 12:41:20
供稿：网友
在了解Asp.net请求处理流程的过程中，个人认为有必要从源代码的角度来了解asp.net管道是怎么实现的。
在此之前大家有必要了解一些asp.net请求流程的基本东东，如ASP.NET 请求处理流程、Asp.net管道、ASP.NET管线与应用程序生命周期
我们大家都知道HttpRuntime主要的方法是
public static void ProcessRequest(HttpWorkerRequest wr)
代码如下:
private void ProcessRequestInternal(HttpWorkerRequest wr)
{
HttpContext context;
try
{
context = new HttpContext(wr, false);
}
catch
{
wr.SendStatus(400, "Bad Request");
wr.SendKnownResponseHeader(12, "text/html; charset=utf-8");
byte[] bytes = Encoding.ASCII.GetBytes("<html><body>Bad Request</body></html>");
wr.SendResponseFromMemory(bytes, bytes.Length);
wr.FlushResponse(true);
wr.EndOfRequest();
return;
}
wr.SetEndOfSendNotification(this._asyncEndOfSendCallback, context);
Interlocked.Increment(ref this._activeRequestCount);
HostingEnvironment.IncrementBusyCount();
try
{
try
{
this.EnsureFirstRequestInit(context);
}
catch
{
if (!context.Request.IsDebuggingRequest)
{
throw;
}
}
context.Response.InitResponseWriter();
IHttpHandler applicationInstance = HttpApplicationFactory.GetApplicationInstance(context);
if (applicationInstance == null)
{
throw new HttpException(SR.GetString("Unable_create_app_object"));
}
if (EtwTrace.IsTraceEnabled(5, 1))
{
EtwTrace.Trace(EtwTraceType.ETW_TYPE_START_HANDLER, context.WorkerRequest, applicationInstance.GetType().FullName, "Start");
}
if (applicationInstance is IHttpAsyncHandler)
{
IHttpAsyncHandler handler2 = (IHttpAsyncHandler) applicationInstance;
context.AsyncAppHandler = handler2;
handler2.BeginProcessRequest(context, this._handlerCompletionCallback, context);
}
else
{
applicationInstance.ProcessRequest(context);
this.FinishRequest(context.WorkerRequest, context, null);
}
}
catch (Exception exception)
{
context.Response.InitResponseWriter();
this.FinishRequest(wr, context, exception);
}
}
我们看到里面有这么一句
IHttpHandler applicationInstance = HttpApplicationFactory.GetApplicationInstance(context);用来获取HttpApplication，而HttpApplication实现了IHttpAsyncHandler接口public class HttpApplication : IHttpAsyncHandler, IHttpHandler, IComponent, IDisposable，最后调用application的BeginProcessRequest方法。
HttpApplicationFactory.GetApplicationInstance(context)主要是调用GetNormalApplicationInstance
代码如下:
internal static IHttpHandler GetApplicationInstance(HttpContext context)
{
if (_customApplication != null)
{
return _customApplication;
}
if (context.Request.IsDebuggingRequest)
{
return new HttpDebugHandler();
}
_theApplicationFactory.EnsureInited();
_theApplicationFactory.EnsureAppStartCalled(context);
