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program Project1;
{$APPTYPE GUI}
{$R *.dres}
uses
Vcl.Forms,
Web.WebReq,
IdHTTPWebBrokerBridge,
FormUnit1 in ‘FormUnit1.pas‘ {Form1},
ServerMethodsUnit1 in ‘ServerMethodsUnit1.pas‘,
WebModuleUnit1 in ‘WebModuleUnit1.pas‘ {WebModule1: TWebModule};
{$R *.res}
begin
{ 返回是什么，见下面的【绿色代码】 }
if WebRequestHandler <> nil then
WebRequestHandler.WebModuleClass := WebModuleClass;
Application.Initialize;
Application.CreateForm(TForm1, Form1);
Application.Run;
end.
IdHTTPWebBrokerBridge单元中：
1 initialization
{** 挂钩 **}
2 WebReq.WebRequestHandlerProc := IdHTTPWebBrokerBridgeRequestHandler; 3 {$IFDEF HAS_CLASSVARS} 4 {$IFNDEF HAS_CLASSDESTRUCTOR} 5 finalization 6 FreeAndNil(TIdHTTPWebBrokerBridgeRequestHandler.FWebRequestHandler); 7 {$ENDIF} 8 {$ELSE} 9 finalization 10 FreeAndNil(IndyWebRequestHandler); 11 {$ENDIF}
WebRequestHandler是Web.WebReq中的一个方法：
1 function WebRequestHandler: TWebRequestHandler; 2 begin 3 if Assigned(WebRequestHandlerProc) then 4 Result := WebRequestHandlerProc /** 指向 IdHTTPWebBrokerBridgeRequestHandler 函数了 **/ 5 else 6 Result := nil; 7 end;
IdHTTPWebBrokerBridgeRequestHandler的定义：
1 function IdHTTPWebBrokerBridgeRequestHandler: TWebRequestHandler; 2 begin 3 {$IFDEF HAS_CLASSVARS} 4 if not Assigned(TIdHTTPWebBrokerBridgeRequestHandler.FWebRequestHandler) then 5 TIdHTTPWebBrokerBridgeRequestHandler.FWebRequestHandler := TIdHTTPWebBrokerBridgeRequestHandler.Create(nil); 6 Result := TIdHTTPWebBrokerBridgeRequestHandler.FWebRequestHandler; 7 {$ELSE} 8 if not Assigned(IndyWebRequestHandler) then 9 IndyWebRequestHandler := TIdHTTPWebBrokerBridgeRequestHandler.Create(nil); 10 Result := IndyWebRequestHandler; 11 {$ENDIF} 12 end;
还记得（一）中的那个静态成员吗? 在第4行初始化了。
继续（一）中 Run 函数中的代码：
1 procedure TIdHTTPWebBrokerBridgeRequestHandler.Run(AThread: TIdContext; ARequestInfo: TIdHTTPRequestInfo; AResponseInfo: TIdHTTPResponseInfo); 2 var 3 LRequest: TIdHTTPAppRequest; 4 LResponse: TIdHTTPAppResponse; 5 begin 6 try 7 LRequest := TIdHTTPAppRequest.Create(AThread, ARequestInfo, AResponseInfo); 8 try 9 LResponse := TIdHTTPAppResponse.Create(LRequest, AThread, ARequestInfo, AResponseInfo); 10 try 11 // WebBroker will free it and we cannot change this behaviour 12 AResponseInfo.FreeContentStream := False; 13 HandleRequest(LRequest, LResponse); 14 finally 15 FreeAndNil(LResponse); 16 end; 17 finally 18 FreeAndNil(LRequest); 19 end; 20 except 21 // Let Indy handle this exception 22 raise; 23 end; 24 end;
TIdHTTPWebBrokerBridgeRequestHandler并没有 override 父类(TWebRequestHandler)的HandleRequest方法. 看TWebRequestHandler.HandleRequest代码
1 function TWebRequestHandler.HandleRequest(Request: TWebRequest; 2 Response: TWebResponse): Boolean; 3 var 4 I: Integer; 5 LWebModule: TComponent; 6 LWebAppServices: IWebAppServices; 7 LGetWebAppServices: IGetWebAppServices; 8 LComponent: TComponent; 9 begin 10 Result := False; 11 LWebModule := ActivateWebModules; 12 if Assigned(LWebModule) then 13 try 14 try 15 if Supports(IInterface(LWebModule), IGetWebAppServices, LGetWebAppServices) then 16 LWebAppServices := LGetWebAppServices.GetWebAppServices; 17 if LWebAppServices = nil then 18 for I := 0 to LWebModule.ComponentCount - 1 do 19 begin 20 LComponent := LWebModule.Components[I]; 21 if Supports(LComponent, IWebAppServices, LWebAppServices) then 22 if LWebAppServices.Active then 23 break 24 else 25 LWebAppServices := nil; 26 end; 27 if LWebAppServices = nil then 28 LWebAppServices := TDefaultWebAppServices.Create; 29 LWebAppServices.InitContext(LWebModule, Request, Response); 30 try 31 try 32 Result := LWebAppServices.HandleRequest; 33 except 34 ApplicationHandleException(LWebAppServices.ExceptionHandler); 35 end; 36 finally 37 LWebAppServices.FinishContext; 38 end; 39 if Result and not Response.Sent then 40 Response.SendResponse; 41 except 42 ApplicationHandleException(LWebAppServices.ExceptionHandler); 43 end; 44 finally 45 DeactivateWebModules(LWebModule); 46 end; 47 end;
在上面代码中，可以看到 WebModule 字眼了， ：）
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原文地址：http://www.cnblogs.com/Jiaojiawang/p/4818506.html
