Creating Chat Application with Borland Delphi/Indy: The Client - Sending a request to the Server
(Page 5 of 5 )
procedure TForm1.btConnectClick(Sender: TObject);
begin
//the mname.text must contain a nickname(this will be the name
recorded by the server upon connection)
if mname.Text='' then begin showmessage('Please enter a
nickname!') ;
exit;
end
else if mname.Text<>'' then
//if there is a name, try to connect
mname.Enabled:=false;
tc.Host:=ip;
tc.Port:=port;
with tc do
begin
try
Connect;
//after you’ve connected,send your name to the server.
Socket.WriteLn(mname.Text);
except on E : Exception do
showmessage('Could not connect to remote host. Check to see
if you entered the right IP address');
end;
end;
end;
//The procedure below sends a text message, it should
contain:to@from:msg
procedure TForm1.btsendClick(Sender: TObject);
begin
if (edto.Text='') and (edmsg.Text='') then begin
edto.Color:=clred;
edto.Color:=clred;
showmessage('You need to enter a message or a name to send
the message to.');
exit;
end;
tc.Socket.WriteLn(edto.text + '@' +edmsg.Text);
end;
procedure TForm1.listnameClick(Sender: TObject);
begin
//request list of connected client names
tc.Socket.WriteLn('listnames@one');
end;
//start the listening/reading thread
procedure TForm1.tcConnected(Sender: TObject);
begin
rt := TReadingThread.Create(tc);
end;
//close the reading/listening thread if client logs off
procedure TForm1.tcDisconnected(Sender: TObject);
begin
if rt <> nil then
begin
rt.Terminate;
rt.WaitFor;
FreeAndNil(rt);
end;
end;
//This procedure automatically adds a client name to the edto.text edit
procedure TForm1.lnamesClick(Sender: TObject);
begin
edto.Text:=lnames.Items[lnames.Itemindex];
end;
//send a message to all connected clients – command ‘all’
procedure TForm1.btsendallClick(Sender: TObject);
begin
tc.Socket.WriteLn('all@'+edmsg.Text+':'+mname.Text);
end;
//show setup form
procedure TForm1.SetupConnection1Click(Sender: TObject);
begin
form3.show;
end;
//Connect to server
procedure TForm1.btConnect2chatClick(Sender: TObject);
begin
if mname.Text='' then begin showmessage('Please enter a
nickname!') ;
exit;
end
else if mname.Text<>'' then
//set connection settings
tc.Host:=ip;
tc.Port:=port;
with tc do
begin
try
Connect;
Socket.WriteLn(mname.Text);
mname.Enabled:=false;
btsendall.Enabled:=true;
btsend.Enabled:=true;
listname.Enabled:=true;
except
//on E : Exception do
showmessage('Could not connect to remote host. Check to see
if you entered the right IP address');
end;
end;
btConnect2chat.Enabled:=false;
end;
//When the chat application is started, it reads the connection
settings from a ini file
//the procedure fromshow shows how it’s done…
//The setup form helps you to set up the connection values you
need.
procedure TForm1.FormShow(Sender: TObject);
var
jnclient : TINIFile;
begin
form1.Height:=444;
form1.Width:=673;
btsendall.Enabled:=false;
btsend.Enabled:=false;
listname.Enabled:=false;
jnclient := TINIFile.Create(ExtractFilePath
(Application.EXEName) + 'jnclient.ini');
try
ip:=jnclient.ReadString('Settings', 'ip address', 'Empty');
port:=jnclient.ReadInteger('Settings', 'port number', 1053);
finally
jnclient.Free;
end;
if (ip= 'Empty') or (port<1) then begin
messagedlg('Your connection details are not set. Click ok to
continue.', mtInformation,[mbOk], 0);
form3.Show;
end;
end;
procedure TForm1.Exit1Click(Sender: TObject);
begin
//Close connection
tc.Disconnect;
close;
end;
procedure TForm1.SetupNewConnection1Click(Sender: TObject);
begin
//open setup form
form3.Show;
end;
procedure TForm1.ExitChat1Click(Sender: TObject);
begin
//close form
tc.Disconnect;
close;
end;
procedure TForm1.About1Click(Sender: TObject);
begin
form4.show;
end;
The next three procedures deal with the progress bar when sending a file to a client. The progress bar will visually show the progress of the file being sent.
Click on the tcpclient component and then go to the object inspectors event tab. Double click on onWork and add the following code:
procedure TForm1.tcWork(ASender: TObject; AWorkMode: TWorkMode;
AWorkCount: Integer);
begin
form5.prog.Position := AWorkCount;
end;
Do the same for WorkBegin.. and WorkEnd…
procedure TForm1.tcWorkBegin(ASender: TObject; AWorkMode: TWorkMode;
AWorkCountMax: Integer);
begin
form5.prog.Max := AWorkCountMax;
form5.prog.Position := 0;
end;
procedure TForm1.tcWorkEnd(ASender: TObject; AWorkMode: TWorkMode);
begin
sleep(300);
form5.edfn.clear;
form5.cb.Clear;
form5.Close;
end;
end.
As you can see from the code, the client starts to send the file, and when the file transfer is completed, the form is closed.
That’s it for now. In the next instalment, I will deal with the actual code that sends a file and also the form that receives a screenshot image to display.
Till next time.
| DISCLAIMER: The content provided in this article is not warranted or guaranteed by Developer Shed, Inc. The content provided is intended for entertainment and/or educational purposes in order to introduce to the reader key ideas, concepts, and/or product reviews. As such it is incumbent upon the reader to employ real-world tactics for security and implementation of best practices. We are not liable for any negative consequences that may result from implementing any information covered in our articles or tutorials. If this is a hardware review, it is not recommended to open and/or modify your hardware. |
