基于IOCP的高速文件传输代码

//服务端：

const

  //transmit用的参数

  TF_USE_KERNEL_APC     = $20;

  //命令类型

  CMD_CapScreen             = 2000;

  CMD_CapVideo              = 2001;

  CMD_CapAudio              = 2002;

  CMD_GetSystemInfo         = 2003;

  CMD_TransmitFiles         = 2004;

  

//通用数据传输包体封装

type

  //每个完整数据的头描述

  TPacketHeader =  packed record

     PacketCMD    : Word;   //包类型

     DataLength   : Word;   //包体长度

     IsCompressed : Boolean; //包体是否为压缩数据

  end;

  TBytes = array [0..65535] of Byte;

  TPacketBody = packed record

     Data : TBytes;

  end;

  //完整的数据包

  TPacketInfo = packed record

    Header : TPacketHeader;

    Body   : TPacketBody;

  end;

  //文件发送包

  TFileSendPacket = packed record

    FileName : array [0..127] of Char;

    FileSize : LongWord;

    StartWritePositon : LongWord;

    hFile : THandle;

  end;

function TServerClientSocket.TransFile(FileName: string;StartWritePositon:LongWord): Boolean;

var

  hFile : THandle;

  NumberOfByteSend : LongWord;

  Block:PBlock;

  PacketInfo: TPacketInfo;

  FileSendPacket : TFileSendPacket;

  AFileName : string[128];

  TransmitFileBuffers : TTransmitFileBuffers;

begin

    if not FileExists(FileName) then

    begin

      Result := False;

      Exit;

    end;

    

    hFile := CreateFile(PChar(FileName), GENERIC_READ, FILE_SHARE_READ, nil, OPEN_EXISTING, 0, 0);

    //如果文件打开错误，则退出

    if hFile = INVALID_HANDLE_VALUE then

    begin

      Result := False;

      Closehandle(hFile);

      Exit;

    end;

    //得到需要传输的字节数

    NumberOfByteSend := windows.GetFileSize(hFile, nil) - StartWritePositon;

    if NumberOfByteSend <= 0 then

    begin

      Closehandle(hFile);

      Exit;

    end;

    Block := AllocBlock;

    Block.Data.Event := seFileSend;

    Block.Data.Overlapped.Offset := StartWritePositon;

    AFileName := ExtractFileName(FileName);

    FillChar(PacketInfo,SizeOf(TPacketInfo),0);

    FillChar(FileSendPacket,SizeOf(TFileSendPacket),0);

    Move(AFileName[1],FileSendPacket.FileName,length(AFileName));

    FileSendPacket.FileSize := NumberOfByteSend;

    FileSendPacket.StartWritePositon := StartWritePositon;

    FileSendPacket.hFile := hFile;

    PacketInfo.Header.PacketCMD := CMD_TransmitFiles;

    PacketInfo.Header.DataLength := Sizeof(TFileSendPacket);

    PacketInfo.Header.IsCompressed := False;

    Move(FileSendPacket,PacketInfo.Body.Data,SizeOf(TFileSendPacket));

    Move(PacketInfo,Block^.Data.Buffer,SizeOf(TPacketHeader) + SizeOf(TFileSendPacket));

    //传输文件前发送的包

    TransmitFileBuffers.Head := @Block^.Data.Buffer[0];

    TransmitFileBuffers.HeadLength := SizeOf(TPacketHeader) + SizeOf(TFileSendPacket);

    //传输文件完毕后发送的包

    TransmitFileBuffers.Tail := nil;

    TransmitFileBuffers.TailLength := 0;

    LogMsg('开始发送文件：' + FileName + ' Size=' + IntToStr(NumberOfByteSend));

    //发送命令，并将文件名、继传点、需要传输的大小传递过去

    if not TransmitFile(SocketHandle, hFile, NumberOfByteSend, MAX_BUFSIZE,

      @Block^.Data.Overlapped, @TransmitFileBuffers, TF_USE_KERNEL_APC) then

    begin

      if GetLastError <> ERROR_IO_PENDING then

      begin

        Result := False;

        Exit;

      end;

    end;

    Result := True;

end;

//如果发送完毕，可以接收到重叠IO的返回结果

    case Block^.Data.Event of

      seFileSend:

      begin

        Block.IsUse := False;

        Move(Block.Data.Buffer,PacketInfo,SizeOf(TPacketHeader) + SizeOf(TFileSendPacket));

        if PacketInfo.Header.PacketCMD = CMD_TransmitFiles then

        begin

           FillChar(FileSendPacket,SizeOf(TFileSendPacket),0);

           Move(PacketInfo.body.data,FileSendPacket,SizeOf(TFileSendPacket));

           Closehandle(FileSendPacket.hFile); //发送完毕，关闭文件句柄

        end;

        LogMsg('文件：' + StrPas(FileSendPacket.FileName) + '  发送完毕！');

        if not PrepareRecv() then Result := RESPONSE_FAIL;       

      end;

      seRead: 。。。。。。。

  

//客户端：

procedure TrecvThread.Execute;

var PacketInfo : TPacketInfo;

    str: string;

    FileSendPacket:TFileSendPacket;

    FileStream:TFileStream;

    FileName :string;

    RecBuf:array[0..1023] of Char;

    RemainByts,RecvedBytes:Integer;

begin

  while (not self.Terminated ) DO

  begin

    cs.CheckForDisconnect(False);

     if cs.ClosedGracefully then

     begin

        Fmm.Lines.Add('链路断开!');

        self.Terminate;

     end;

     cs.ReadBuffer(PacketInfo.Header,SizeOf(TPacketHeader));

     cs.ReadBuffer(PacketInfo.Body.Data, PacketInfo.Header.DataLength);

     if PacketInfo.Header.PacketCMD = CMD_TransmitFiles then

     begin

       Move(PacketInfo.Body.Data,FileSendPacket,PacketInfo.Header.DataLength);

       FileName := StrPas(FileSendPacket.FileName);

       try

         FileStream := TFileStream.Create('C:'+ FileName, fmCreate or fmOpenWrite);

         Fmm.Lines.Add('接收：' + FileName + ' Size=' + IntToStr(FileSendPacket.FileSize));

         RecvedBytes := 0;

         while (RecvedBytes < FileSendPacket.FileSize) do

         begin

           if FileSendPacket.FileSize <= 1024 then

           begin

             cs.ReadBuffer(RecBuf,FileSendPacket.FileSize);

             RecvedBytes := FileSendPacket.FileSize;

             FileStream.WriteBuffer(RecBuf,RecvedBytes);

             Break;

           end else begin

             cs.ReadBuffer(RecBuf,1024);

             RecvedBytes := RecvedBytes + 1024;

             FileStream.WriteBuffer(RecBuf,1024);

             RemainByts := FileSendPacket.FileSize - RecvedBytes;

             if RemainByts <= 1024 then

             begin

               cs.ReadBuffer(RecBuf,RemainByts);

               RecvedBytes := RecvedBytes + RemainByts;

               FileStream.WriteBuffer(RecBuf,RemainByts);

               Break;

             end;

           end;

         end;

       finally

          FileStream.Free;

       end;

     end;

  end;

end;

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