IdHTTP Get下载网络文件时经常卡死

chinawcs 2015-07-20 08:27:27

我是循环下载很多网络文件，但是下载过程中会经常卡死不动而且没有异常抛出。主线程放IdAntiFreeze1 或者下载部分放单独线程也会卡死。

IdHTTP 是阻塞的有没有好的替代方案



var



  IdHTTP: TIdHttp;

  MemStream: TMemoryStream;

  UrlStr, DFileName: string;

  FilePosition: int64;

  FileSize: Integer;



begin

  IdHTTP := TIdHttp.Create(nil);

  IdHTTP.ProtocolVersion := pv1_1;

  // IdHttp.RecvBufferSize := 1024 ;

  IdHTTP.HandleRedirects := true;

  IdHTTP.ConnectTimeout :=60000;

  IdHTTP.ReadTimeout :=60000;

  IdAntiFreeze1.OnlyWhenIdle:=False;//设置使程序有反应.



  lbl_error.Caption:='0';

  tmr_dwonerror.Enabled :=true;

  try

    // 获取重定向后的下载地址和文件大小

    IdHTTP.Head(FASrcURL);

    FileSize := IdHTTP.Response.ContentLength;



    if FileSize <= 0 then

      exit;



    {

      DFileName := idhttp.URL.URI;

      //由下载地址转换为保存文件名

      while pos('/',DFileName) > 0 do

      begin

      delete(DFileName, 1, pos('/',DFileName));

      end;

      while pos('/',DFileName) > 0 do

      begin

      delete(DFileName, 1, pos('/',DFileName));

      end;

      if DFileName = '' then

      exit;

    }



    FilePosition := 0;

    MemStream := TMemoryStream.Create;



    cxProgressBar1.Properties.Max :=FileSize;



    while FilePosition < FileSize do

    begin

      // 方法1：未验证

      // IdHttp.Request.ContentRangeStart := FilePosition;

      // IdHttp.Request.ContentRangeEnd   := FilePosition + 1024;

      // 方法2：已验证

      try

      IdHTTP.Request.Range := IntToStr(FilePosition) + '-';

      if FilePosition + 10240 < FileSize then

        IdHTTP.Request.Range := IdHTTP.Request.Range +

          IntToStr(FilePosition + 10239);



      IdHTTP.get(IdHTTP.URL.URI, MemStream);

      // MemStream.LoadFromStream(IdHttp.Response.ContentStream);

      MemStream.SaveToFile(FASaveFileName);



      FilePosition := MemStream.Size;

      cxProgressBar1.Position := FilePosition;

      Application.ProcessMessages;

      except

        exit;

      end;

      // sleep(50);

    end;

    tmr_dwonerror.Enabled :=false;

    Result := true;

  finally

    IdHTTP.Free;

    MemStream.Free;

    cxProgressBar1.Position:=0;

  end;