读DataSnap源代码(四)

继续篇中的

 function TCustomWebDispatcher.DispatchAction(Request: TWebRequest;
Response: TWebResponse): Boolean;
var
I: Integer;
Action, Default: TWebActionItem;
Dispatch: IWebDispatch;
begin
FRequest := Request;
FResponse := Response;
I := ;
Default := nil;
if Response.Sent then
begin
Result := True;
{ Note that WebSnapSvr enabled apps have no way to mark response as sent }
Exit;
end;
Result := DoBeforeDispatch(Request, Response) or Response.Sent;
while not Result and (I < FActions.Count) do
begin
Action := FActions[I];
Result := Action.DispatchAction(Request, Response, False);
if Action.Default then Default := Action;
Inc(I);
end;
// Dispatch to self registering components
I := ;
while not Result and (I < FDispatchList.Count) do
begin
if Supports(IInterface(FDispatchList.Items[I]), IWebDispatch, Dispatch) then
begin
Result := DispatchHandler(Self, Dispatch,
Request, Response, False);
end;
Inc(I);
end; if not Result and Assigned(Default) then
Result := Default.DispatchAction(Request, Response, True);
if Result and not Response.Sent then
Result := DoAfterDispatch(Request, Response); end;

在第26行代码之前,是执行WebModule中的Action, 然后是遍例WebModule上的Component, 只要支持IWebDispatch,都有机会处理WEB请求。

当然就包括了   TDSHTTPWebDispatcher = class(TDSHTTPServerTransport, IWebDispatch)。 继续代码:

 function DispatchHandler(Sender: TObject; Dispatch: IWebDispatch; Request: TWebRequest; Response: TWebResponse;
DoDefault: Boolean): Boolean;
begin
Result := False;
if (Dispatch.Enabled and ((Dispatch.MethodType = mtAny) or
(Request.MethodType = Dispatch.MethodType)) and
Dispatch.Mask.Matches(string(Request.InternalPathInfo))) then
begin
Result := Dispatch.DispatchRequest(Sender, Request, Response);
end;
end;
function TDSHTTPWebDispatcher.DispatchRequest(Sender: TObject;
Request: TWebRequest; Response: TWebResponse): Boolean;
begin
try
if Owner is TWebModule then
DataSnapWebModule := TWebModule(Owner);
try
try
RequiresServer;
TDSHTTPServerWebBroker(Self.FHttpServer).DispatchDataSnap(Request, Response);
Result := True;
except
on E: Exception do
begin
{ Default to 500, like web services. }
Response.StatusCode := 500;
Result := True;
end;
end;
except
{ Swallow any unexpected exception, it will bring down some web servers }
Result := False;
end;
finally
{ Reset current DataSnapWebModule }
DataSnapWebModule := nil;
end;
end;

至此,WEB请求转入到WebModule中的TDSHTTPWebDispatcher来处理了。

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