SetGlobalOnLoadExternalResourceHandlerEx

Syntax

Delphi

TFlashPlayerControlOnGlobalLoadExternalResourceEx = procedure(
  const URL: WideString;
  Stream: TStream;
  out bHandled: Boolean) of object;
 
procedure SetGlobalOnLoadExternalResourceHandlerEx(Handler: TFlashPlayerControlOnGlobalLoadExternalResourceEx);

C++Builder

typedef void __fastcall (__closure *TFlashPlayerControlOnGlobalLoadExternalResourceEx)(
   const System::WideString URL, 
   Classes::TStream* Stream, 
   /* out */ bool &bHandled);
 
void __fastcall SetGlobalOnLoadExternalResourceHandlerEx(TFlashPlayerControlOnGlobalLoadExternalResourceEx Handler);

Description

The SetGlobalOnLoadExternalResourceHandlerEx procedure registers a global handler that allows you to intercept and provide the content of external resources requested by Flash movies.

Unlike SetGlobalOnLoadExternalResourceHandler, the Ex variant enables asynchronous streaming of content. This is useful for large resources such as Flash Video (FLV) files, where providing data incrementally avoids blocking the application and prevents Flash from preallocating excessive memory:

var netConn:NetConnection = new NetConnection();
netConn.connect(null);
var netStream:NetStream = new NetStream(netConn);
my_video.attachVideo(netStream);
netStream.setBufferTime(0);
netStream.play("http://FLV/FlashVideo.flv");

When the Flash movie requests http://FLV/FlashVideo.flv, the registered handler is called. If bHandled is set to True, you can provide the content asynchronously through the provided Stream:

type
  TMainForm = class(TForm)
    procedure FormCreate(Sender: TObject);
// ...
 
  private
    procedure OnGlobalLoadExternalResourceEx(const URL: WideString; Stream: TStream; out bHandled: Boolean);
// ...
 
  end;
 
  TContentProvideThread = class(TThread)
  protected
    procedure Execute; override;
end;
// ...
 
procedure TMainForm.FormCreate(Sender: TObject);
begin
    SetGlobalOnLoadExternalResourceHandlerEx(OnGlobalLoadExternalResourceEx);
end;
// ...
 
procedure TMainForm.OnGlobalLoadExternalResourceEx(const URL: WideString; Stream: TStream; out bHandled: Boolean);
var
  ResourceStream: TResourceStream;
  ContentProvideThread: TContentProvideThread;
begin
    if URL = 'http://FLV/FlashVideo.flv' then
    begin
        bHandled := true; // Notify flash that we are ready to provide content
 
        // Create new thread to provide data
        ContentProvideThread := TContentProvideThread.Create(Stream);
    end;
end;
// ...
 
procedure TContentProvideThread.Execute;
begin
   // Copy data from source stream to Stream
   ResourceStream := TResourceStream.Create(0, 'FlashVideo', 'FLV');
   ResourceStream.SaveToStream(Stream);
   ResourceStream.Free;
end;

class TMainForm : public TForm
{
__published:
        void __fastcall FormCreate(TObject *Sender);
// ...
 
private:
        void __fastcall OnGlobalLoadExternalResourceEx(const WideString URL, Classes::TStream* Stream, bool &bHandled);
// ...
 
}
// ...
 
void __fastcall TMainForm::FormCreate(TObject *Sender)
{
  SetGlobalOnLoadExternalResourceHandler(OnGlobalLoadExternalResource);
}
// ...
 
void __fastcall TMainForm::OnGlobalLoadExternalResource(const WideString URL, Classes::TStream* Stream, bool &bHandled)
{
  if (URL == WideString("http://FLV/FlashVideo.flv"))
  {
    bHandled = true; // Notify flash that we are ready to provide content
 
    // Create new thread to provide data
    // class TContentProvideThread: public TThread so far...
    TContentProvideThread* ContentProvideThread = 
       new TContentProvideThread(Stream);
  }
}
...
 
void __fastcall TContentProvideThread::Execute()
{
    TResourceStream* ResourceStream = new TResourceStream(0, "FlashVideo", "FLV");
    ResourceStream->SaveToStream(Stream);
    delete ResourceStream;
}