Indy TIdTCPClient receive text
I try to receive text in a idtcpclient but it does not work. This is the code that I use in a timer:
procedure TForm1.Timer2Timer(Sender: TObject);
var
receivedtext:string;
begin
if idtcpclient1.Connected = true then
begin
with idtcpclient1 do
begin
if not IOHandler.InputBufferIsEmpty then
begin
try
receivedtext := IOHandler.ReadLn;
finally
if receivedtext = '' = false then
begin
showmessage(receivedtext);
idtcpclient1.IOHandler.InputBuffer.Clear;
receivedtext := '';
end;
end;
end;
end;
end
else
begin
timer2.Enabled := false;
end;
end;
The interval of the timer is 8 ms. The timer is automatically enabled on connect. But I don't get an messagebox or an error when I send something. I am sure that I written the data because when I use tclientsocket I do receive it.
What I am doing wrong?
Use something more like this instead:
procedure TForm1.Timer2Timer(Sender: TObject);
var
receivedtext: string;
begin
with IdTCPClient1 do
begin
try
if IOHandler.InputBufferIsEmpty then
begin
IOHandler.CheckForDataOnSource(0);
IOHandler.CheckForDisconnect;
if IOHandler.InputBufferIsEmpty then Exit;
end;
receivedtext := IOHandler.ReadLn;
except
Timer2.Enabled := False;
Exit;
end;
if receivedtext <> '' then
ShowMessage(receivedtext);
end;
end;
With that said, this kind of code would be better implemented using a worker thread instead of a timer.
1 - Create a new class derived from TThread (File > New > Other > Thread Object)
type
TDataEvent = procedure(const Data: string) of object;
TReadingThread = class(TThread)
private
FClient: TIdTCPClient;
FData: string;
FOnData: TDataEvent;
procedure DataReceived;
protected
procedure Execute; override;
public
constructor Create(AClient: TIdTCPClient); reintroduce;
property OnData: TDataEvent read FOnData write FOnData;
end;
constructor TReadingThread.Create(AClient: TIdTCPClient);
begin
inherited Create(True);
FClient := AClient;
end;
procedure TReadingThread.Execute;
begin
while not Terminated do
begin
FData := IdTCPClient1.IOHandler.ReadLn;
if (FData <> '') and Assigned(FOnData) then
Synchronize(DataReceived);
end;
end;
procedure TReadingThread.DataReceived;
begin
if Assigned(FOnData) then
FOnData(FData);
end;
2 - Modify your connection code:
IdTCPClient1.Connect;
try
Thread := TReadingThread.Create(IdTCPClient1);
Thread.OnData := DataReceived;
Thread.Resume;
except
IdTCPClient1.Disconnect;
raise;
end;
...
if Assigned(Thread) then Thread.Terminate;
try
IdTCPClient1.Disconnect;
finally
if Assigned(Thread) then
begin
Thread.WaitFor;
FreeAndNil(Thread);
end;
end;
...
procedure TForm1.DataReceived(const Data: string);
begin
ShowMessage(Data);
end;