Pascal (Lazarus/Delphi)

POP3 SSH Tunneling (Port Forwarding)

Demonstrates how to connect to a POP3 server through an SSH tunnel. Reads a POP3 mailbox and display the FROM and SUBJECT header fields of each email. Pascal (Lazarus/Delphi)

program ChilkatDemo;

// Demonstrates using the Chilkat Pascal wrapper via the C bridge DLL.
// Builds as a console application under Lazarus (FPC) or Delphi.

{$IFDEF FPC}
  {$MODE DELPHI}
{$ENDIF}
{$APPTYPE CONSOLE}

uses
  {$IFDEF UNIX}
  cthreads,
  {$ENDIF}
  SysUtils,
  CkDllLoader,
  Chilkat.MailMan,
  Chilkat.Email;

// ---------------------------------------------------------------------------

procedure RunDemo;
var
  success: Boolean;
  mailman: TMailMan;
  sshHostname: string;
  sshPort: Integer;
  numToDownload: Integer;
  i: Integer;
  email: TEmail;

begin
  success := False;

  //  This example requires the Chilkat API to have been previously unlocked.
  //  See Global Unlock Sample for sample code.

  //  The mailman object is used for receiving (POP3) 
  //  and sending (SMTP) email.
  mailman := TMailMan.Create;

  //  The SSH hostname may be a hostname or an 
  //  IP address, such as "192.168.1.108".
  //  The port is typically 22 (the standard port for SSH).
  sshHostname := 'sftp.example.com';
  sshPort := 22;

  //  Connect to an SSH server and establish the SSH tunnel:
  success := mailman.SshOpenTunnel(sshHostname,sshPort);
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;

  //  Authenticate with the SSH server via a login/password
  //  or with a public key.
  //  This example demonstrates SSH password authentication.
  //  Note: This is not authenticating with the POP3 server, it is
  //  for authenticating with the SSH server, which is separate.
  success := mailman.SshAuthenticatePw('ssh_login','ssh_password');
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;

  //  OK, the SSH tunnel is setup.  The mailman may
  //  be used exactly the same as usual, except all communications
  //  are now sent through the SSH tunnel.

  //  The SSH tunnel may be kept open for any number of 
  //  POP3 connections.  

  //  Set the POP3 server's hostname
  mailman.MailHost := 'mail.my-pop3-server.com';

  //  Set the POP3 settings for your POP3 server:
  mailman.PopUsername := 'pop3_login';
  mailman.PopPassword := 'pop3_password';
  mailman.MailPort := 995;
  mailman.PopSsl := True;

  //  Connect to the POP3 server through the already-established SSH tunnel:
  success := mailman.Pop3BeginSession();
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;

  //  A visual inspection of the LastErrorText after
  //  a successful POP3 connection will confirm the SSH tunneling.
  //  Note: If the POP3 connection uses SSL/TLS, then the SSL/TLS 
  //  secure channel will be wrapped within the SSH tunnel.
  WriteLn(mailman.LastErrorText);

  //  How many messages are in the POP3 inbox?
  numToDownload := mailman.GetMailboxCount();
  if (numToDownload > 5) then
    begin
      numToDownload := 5;
    end;
  if (numToDownload = 0) then
    begin
      WriteLn('No messages in the POP3 inbox.');
      Exit;
    end;

  //  Download a max of 5 messages

  email := TEmail.Create;
  for i := 1 to numToDownload do
    begin
      success := mailman.FetchOne(False,0,i,email);
      if (success = False) then
        begin
          WriteLn(mailman.LastErrorText);
          Exit;
        end;

      WriteLn(email.From);
      WriteLn(email.Subject);
      WriteLn('----');
    end;

  //  Close the connection with the POP3 server, leaving the SSH tunnel open for subsequent POP3 connections.
  success := mailman.Pop3EndSession();
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;

  //  Try connecting to a different POP3 server through the same aleady setup SSH tunnel:
  //  Set the POP3 server's hostname
  mailman.MailHost := 'mail.my-pop3-server2.com';

  //  Set the POP3 settings for your POP3 server:
  mailman.PopUsername := 'pop3_login2';
  mailman.PopPassword := 'pop3_password2';
  mailman.MailPort := 110;
  mailman.PopSsl := False;

  success := mailman.Pop3BeginSession();
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;

  //  Review the LastErrorText to see that the connection was made via the SSH tunnel:
  WriteLn(mailman.LastErrorText);

  success := mailman.Pop3EndSession();
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;

  //  Close the SSH tunnel.
  success := mailman.SshCloseTunnel();
  if (success = False) then
    begin
      WriteLn(mailman.LastErrorText);
      Exit;
    end;


  mailman.Free;
  email.Free;

end;

// ---------------------------------------------------------------------------

begin

  try
    RunDemo;
  except
    on E: Exception do
      WriteLn('Unhandled exception: ', E.ClassName, ': ', E.Message);
  end;

  WriteLn;
  {$IFDEF MSWINDOWS}
  WriteLn('Press Enter to exit...');
  ReadLn;
  {$ENDIF}
end.