我想将数据从TIdTCPServer传输到TIdTCPClient。
在服务器端,我有:
procedure TForm1.IdTCPServer1Execute(AContext: TIdContext);
var x:Integer;
Received:String;
SendBuff:TBytes;
hFile:THandle;
fSize:Int64;
begin
fSize:=0;
if MOpenFileForRead(hFile,MGetExePath+'\test.jpg') then begin
fSize:=MFileSize(hFile);
SetLength(SendBuff,fSize);
MReadFile(hFile,SendBuff[0],fSize);
MCloseFile(hFile);
end;
// ... here the SendBuff contains valid data, I checked.
repeat
Received:=AContext.Connection.Socket.ReadLn;
if not AContext.Connection.Connected then Exit;
if Received=CMD_TEST_FILE then begin
AContext.Connection.Socket.Write(fSize);
AContext.Connection.Socket.WriteBufferOpen;
AContext.Connection.Socket.Write(SendBuff);
AContext.Connection.Socket.WriteBufferClose;
end;
until False;
end;
客户方:
procedure TForm1.Button2Click(Sender: TObject);
var fSize:Int64;
RecvBuff:TBytes;
hFile:THandle;
begin
IdTCPClient1.Socket.WriteLn(CMD_TEST_FILE);
fSize:=IdTCPClient1.Socket.ReadInt64;
SetLength(RecvBuff,fSize);
IdTCPClient1.Socket.ReadBytes(RecvBuff,fSize);
if MCreateFile(hFile, MGetExePath+'\new.jpg') then begin
MWriteFile(hFile,RecvBuff[0],fSize);
MCloseFile(hFile);
end;
Memo1.Lines.Add('ok');
end;
......但它不起作用。我检查了所使用的读写数据函数,它们没问题。在服务器上,缓冲区设置为ok,文件大小到达客户端ok,但客户端缓冲区的内容只是零。
P.S:我想以这种方式发送文件而不是流或其他任何东西。
答案 0 :(得分:3)
如果你查看ReadBytes()
的签名,它有一个可选的AAppend
参数默认为True:
procedure ReadBytes(var VBuffer: TIdBytes; AByteCount: Integer; AAppend: Boolean = True); virtual;
如果为true,则从套接字读取字节并将它们附加到现有字节数组的末尾。由于您预先分配了数组,因此初始字节未定义,文件字节在未定义的字节之后。
要解决此问题,您需要:
停止预先分配字节数组,让ReadBytes()
为您分配。
procedure TForm1.Button2Click(Sender: TObject);
var
fSize: Int64;
RecvBuff: TBytes;
hFile: THandle;
begin
IdTCPClient1.Socket.WriteLn(CMD_TEST_FILE);
fSize := IdTCPClient1.Socket.ReadInt64;
// SetLength(RecvBuff,fSize); // <-- remove this line
IdTCPClient1.Socket.ReadBytes(RecvBuffer, fSize);
if MCreateFile(hFile, MGetExePath+'\new.jpg') then
begin
MWriteFile(haile, RecvBuff[0], fSize);
MCloseFile(hFile);
end;
Memo1.Lines.Add('ok');
end;
预先分配数组,但将AAppend
设置为False,以便字节填充现有数组而不是附加到它。
procedure TForm1.Button2Click(Sender: TObject);
var
fSize: Int64;
RecvBuff: TBytes;
hFile: THandle;
begin
IdTCPClient1.Socket.WriteLn(CMD_TEST_FILE);
fSize := IdTCPClient1.Socket.ReadInt64;
SetLength(RecvBuff, fSize);
IdTCPClient1.Socket.ReadBytes(RecvBuff, fSize, False);
if MCreateFile(hFile, MGetExePath+'\new.jpg') then
begin
MWriteFile(haile, RecvBuff[0], fSize);
MCloseFile(hFile);
end;
Memo1.Lines.Add('ok');
end;
更新:话虽如此,我强烈建议您改用TStream
,尽管您说不想这样做。它将大大简化代码和内存管理,而不会破坏您选择使用的通信协议:
procedure TForm1.IdTCPServer1Connect(AContext: TIdContext);
begin
AContext.Data := TFileStream.Create(MGetExePath+'\test.jpg', fmOpenRead or fmShareDenyWrite);
AContext.Connection.IOHandler.LargeStream := True;
end;
TForm1.IdTCPServer1Execute(AContext: TIdContext);
var
Received: String;
begin
Received := AContext.Connection.IOHandler.ReadLn;
if Received = CMD_TEST_FILE then
begin
AContext.Connection.IOHandler.Write(TStream(AContext.Data), 0, True);
end;
end;
procedure TForm1.Button2Click(Sender: TObject);
var
FileName: string;
Strm: TStream;
begin
FileName := MGetExePath+'\new.jpg';
Strm := TFileStream.Create(FileName, fmCreate);
try
try
IdTCPClient1.IOHandler.WriteLn
(CMD_TEST_FILE);
IdTCPClient1.IOHandler.ReadStream(Strm, -1, False);
finally
Strm.Free;
end;
except
DeleteFile(FileName);
raise;
end;
Memo1.Lines.Add('ok');
end;