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- ASP.NET Process Model之一：IIS 和 ASP.NET ISAPI
- ASP.NET Process Model之二：ASP.NET Http Runtime Pipeline[上篇]
- ASP.NET Process Model之二：ASP.NET Http Runtime Pipeline[下篇]
現在我們真正進入ASP.NET管轄的范疇，下圖基本上囊括整個處理過程涉及的對象，接下來我們一起來討論這一系列的對象如何相互協作去處理Http Request，并最終生成我們所需的Http Response。
HttpContext
上面我們介紹了ISAPI在調用ISAPIRuntime的時候將對應的ISAPI ECB Pointer作為參數傳遞給了ProcessRequest方法，這個ECB pointer可以看成是托管環境和非托管環境進行數據交換的唯一通道，Server Variable和Request Parameter通過它傳入ASP.NET作為進一步處理的依據，ASP.NET最后生成的Response通過它傳遞給ISAPI，并進一步傳遞給IIS最終返回到Client端。
借助這個傳進來的ECB Pointer，我們創建了一個ISAPIWorkerRequest。ISAPIWorkerRequest作為參數傳入HttpRuntime.ProcessRequestNoDemand的調用。HttpRuntime.ProcessRequestNoDemand最終體現在調用ProcessRequestInternal。下面是真個方法的實現：
ProcessRequestInternal
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);
}
}
NET技術：ASP.NET Process Model之二：ASP.NET Http Runtime Pipeline[下篇]，轉載需保留來源！
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