Borland Delphi Telnet Sample Source Code

ActiveSocket provides an easy-to-use development interface to a variety of IP protocols. By using ActiveSocket, you can very easily create or enhance applications with network features.

ActiveSocket features the following: ICMP, HTTP and HTTPs with support for proxy servers and secure web sites, Telnet, NTP time protocol, RSH remote shell script interface, SNMP (Simple Network Management Protcol), SNMP Traps, Sockets (TCP and UDP), WOL (Wake-On-LAN), and more.

ActiveSocket can be well integrated into Borland Delphi environments. This document describes how the ActiveSocket Toolkit can be integrated into Borland Delphi projects.

Step 1: Download and install the ActiveSocket Toolkit

Download the ActiveSocket from the ActiveXperts Download Site and start the installation. The installation guides you through the installation process.

Step 2: Create a new Delphi Project

Launch Borland Delphi (for instance 'Delphi 2005') from the Start menu. Choose 'New' from the 'File' menu and select your preferred kind of application, for instance: 'VCL Forms Application - Delphi for Win32'. A new Form is displayed in the workspace.

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Step 3: Refer to the ActiveSocket Library and create the objects

Now that a new project has been created, you must add a reference to ActiveSocket in the project to be able to use the ActiveSocket object. To do so, choose 'Import Component...' from the 'Component' menu. The Import Components' dialog appears. Select 'Import a Type Library':

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In the 'Registered Type Libraries' page, select 'ActiveSocket 3.1 Type Library' and click 'Next':

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In the 'Components' page, leave all fields default and click 'Next':

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In the 'Install' page, select 'Create Unit' and click 'Next':

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The interface code is generated now and is shown in the ASOCKETLib_TLB tab of the project.

Step 4: Declare and create the object

From the Project Manager, open Unit1.bas and add the ASOCKETLib_TLB to the 'Uses' statement to refer to the ActiveSocket library:

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In the 'private' or 'public' section, declare the following objects:

   objSocket    : ITcp

You can now create the objects, for instance in the 'FormCreate' function:

   objSocket     := TTcp.Create(Form1).DefaultInterface;

Step 5: Setting up a telnet session

You can now setup a TCP connection to a server.

The following code shows how to create a simple telnet client:

unit Unit1;

interface

uses
  Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
  Dialogs, ASOCKETLib_TLB, StdCtrls, ExtCtrls;

type
  TForm1 = class(TForm)
    EditServer: TEdit;
    EditCommand: TEdit;
    ButtonConnect: TButton;
    ButtonDisconnect: TButton;
    ButtonSend: TButton;
    Panel1: TPanel;
    MemoReceived: TMemo;
    Panel2: TPanel;
    EditResult: TEdit;
    Label1: TLabel;
    Panel3: TPanel;
    Label2: TLabel;
    Label3: TLabel;
    Timer1: TTimer;
    procedure Timer1Timer(Sender: TObject);
    procedure ButtonSendClick(Sender: TObject);
    procedure ButtonDisconnectClick(Sender: TObject);
    procedure ButtonConnectClick(Sender: TObject);
    procedure FormCreate(Sender: TObject);
  private
    objSocket : ITcp;
  public
    { Public declarations }
  end;

var
  Form1: TForm1;

implementation

{$R *.dfm}

{//////////////////////////////////////////////////////////////////////////////}

procedure TForm1.FormCreate(Sender: TObject);
begin
  objSocket := TTcp.Create(Form1).DefaultInterface;
  objSocket.Protocol := objSocket.asPROTOCOL_TELNET;
end;

{//////////////////////////////////////////////////////////////////////////////}

procedure TForm1.ButtonConnectClick(Sender: TObject);
begin
  objSocket.Connect( EditServer.Text, 23);

  EditResult.Text := 'CONNECT: ' + IntToStr ( objSocket.LastError ) + ' - ' + objSocket.GetErrorDescription( objSocket.LastError );

  if ( objSocket.LastError = 0 ) then begin
    EditCommand.Enabled := True;
    ButtonSend.Enabled := True;
    ButtonDisconnect.Enabled := True;
    MemoReceived.Enabled := True;
    ButtonConnect.Enabled := False;
  end;
end;

{//////////////////////////////////////////////////////////////////////////////}

procedure TForm1.ButtonDisconnectClick(Sender: TObject);
begin
  objSocket.Disconnect ();

  EditResult.Text := 'DISCONNECT: ' + IntToStr ( objSocket.LastError ) + ' - ' + objSocket.GetErrorDescription( objSocket.LastError );

  EditCommand.Enabled := False;
  ButtonSend.Enabled := False;
  ButtonDisconnect.Enabled := False;
  MemoReceived.Enabled := False;
  ButtonConnect.Enabled := True;
end;

{//////////////////////////////////////////////////////////////////////////////}

procedure TForm1.ButtonSendClick(Sender: TObject);
begin
  objSocket.SendString( EditCommand.Text, 1);

  EditResult.Text := 'SEND: ' + IntToSTr ( objSocket.LastError ) + ' - ' + objSocket.GetErrorDescription( objSocket.LastError );
end;

{//////////////////////////////////////////////////////////////////////////////}

procedure TForm1.Timer1Timer(Sender: TObject);
begin
  while ( objSocket.HasData = -1 ) do MemoReceived.Lines.Add( objSocket.ReceiveString () );
end;

{//////////////////////////////////////////////////////////////////////////////}

end.

There are many working samples included with the product. You can also find them on the ActiveXperts FTP site: ftp.activexperts-labs.com/samples/asocket.

NOTE: Demo Projects are created with Borland Delphi 7

The ActiveSocket project ships with a set of samples for Borland Delphi. The projects are created with Borland Delphi 7.
Users with a later version of Borland Delphi 7 can open such a project. The Borland Conversion Wizard will guide you through the process of converting the project to the version used.

The ActiveSocket tool is a Network Communications ActiveX software component (SDK). This control supports SNMP, SMTP, POP3, Telnet, TCP, NTP, RSH, HTTP, HTTPs, FTP, DNS, ICMP and more, and can be used by any Windows development platform, including Visual Basic .NET, Visual CSharp .NET, ASP .NET (VB,CS), ASP, Visual Basic, Visual Studio/Visual C++, Delphi, PHP, ColdFusion, HTML, VBScript and any other ActiveX/COM compliant platform. The ActiveSocket Toolkit is an ActiveXperts Software B.V. Product.