CODEWITHSUNDEEP
delphisocketsindy
runfastman
runfastman

Reputation: 947

Indy TCP client ReadLn function hangs

I had a socket communication with a Python server using TClientSocket. After realizing I couldn't have more than on client using TClientSocket I decided to use INDY. I made a little test app using Delphi Indy for the client and server. This worked.

However it now does not work with Python. Python receives connection and the messages just fine, but when it responds, my Delphi gets nothing. My call to fIdTCPClient1.IOHandler.ReadLn() just sits there forever.

Is there something special you have to do to send messages to INDY from a non INDY Server?

procedure TForm3.Button3Click(Sender: TObject);
begin
  fIdTCPClient1 := TIdTCPClient.Create(nil);
  fIdTCPClient1.Port := 20200;
  fIdTCPClient1.Host := '127.0.0.1';//'localhost';
  fIdTCPClient1.Connect;
  fIdTCPClient1.IOHandler.WriteLn('You there');

  msg := fIdTCPClient1.IOHandler.ReadLn();
  ShowMessage(msg);
end;

Connection on the Python side

    HOST = '127.0.0.1'                                  # Localhost
    PORT = 20200 

    s = socket.socket(socket.AF_INET, socket.SOCK_STREAM)
    try:
        s.bind((HOST, PORT))
        s.listen(1)
    except socket.error:
        s.close()
        s = None
        return -1

Python Send/Recieve

data = conn.recv(4096).strip()
print data
conn.send('I am here')

Upvotes: 2

Views: 3322

Answers (1)

7profy
7profy

Reputation: 11

Function IdTCPClient1.IOHandler.ReadLn() hang and wait until receive "end of line" (#13#10 or \r\n) from server. Add on server side response with \r\n at end.

Upvotes: 1

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