delphi – 维护N个同时HTTP下载

如果您不喜欢线程,您还可以创建一个在启动时获取输入参数的exe并将内容下载到指定位置.

请注意,如果您从不同的来源下载,同时下载许多文件只会有所帮助,如果不是,您仍然会受到您唯一来源的带宽的限制,并且还会产生线程开销.

这是我的线程单元和Indy for HTTP的代码,例如,因为它很容易理解：

procedure TfMain.FormCreate(Sender: TObject);
var
  Task: ITask;
begin
  FTaskPool.DynamicSize := cbDynamicPoolSize.Checked;
  FTaskPool.MinPoolSize := StrToInt(ePoolSize.Text);
  FTaskPool.OnTaskMessage := OnTaskMessage;
  FTaskPool.Initialize;

  for I := 1 to NumberOfDownloads do
  begin
    Task := FTaskPool.AcquireTask(OnTaskExecute,'HTTPDownload');
    Task.Values.Ensure('TargeFile').AsString := aFileName;
    Task.Values.Ensure('URL').AsString := aDownloadURL;
    Task.Run;
  end;
end;

procedure TfMain.OnTaskExecute(const Task: ITask);
var
  HTTPClient: TIdHTTP;
  FileStream: TFileStream;
begin
  HTTPClient := TIdHTTP.Create(nil);
  try
    FileStream := TFileStream.Create(Task.Values.Get('TargeFile').AsString,fmCreate);
    try
      HTTPClient.Get(Task.Values.Get('URL').AsInteger,FileStream);
      Task.Message.Ensure('Result').AsString := 'Success';
      Task.SendMessageAsync;
    finally
      FileStream.Free;
    end;   
  finally
    HTTPClient.Free;
  end;
end;

procedure TfMain.OnTaskMessage(const Msg: ITaskValues);
begin
  // do something when a single download has finished
end;