Indy TidTCPServer OnExecute sample that shows the idea how to process an incoming XML file

TCPDemo.pas

procedure TFormMain.ProcessXml(const AXml: string);
begin
  var
  LXmlDoc := TXMLDocument.Create(nil);
  try
    LXmlDoc.DOMVendor := DOMVendors.Find(OmniXML4Factory.Description);
    LXmlDoc.LoadFromXML(AXml);
    // if AXml is invalid, then an exception will be thrown
    // Do further processing here
  finally
    FreeAndNil(LXmlDoc);
  end;
end;

procedure TFormMain.TCPServerExecute(AContext: TIdContext);
begin
  var
  LXML := AContext.Connection.IOHandler.Readln;
  try
    ProcessXml(LXML);
    AContext.Connection.IOHandler.WriteLn('ok');
  except
    on e: Exception do
    begin
      AContext.Connection.IOHandler.WriteLn('Error: No valid XML received - disconnecting!');
    end;
  end;

  // Processing done
  // Disconnect the client, and try to notify it.
  // If you just "exit" here, then the connection will be keept - which is useful only if you
  // want to send some feedback to the client at a later point in time, or if you expect the
  // client to re-use the existing connection for further commands.
  // This will disconnect us, but there is no way to tell if the client recognizes the disconnect.
  AContext.Connection.Disconnect;
end;