Pascal (Lazarus/Delphi)

IMAP Use Existing SSH Tunnel

Demonstrates how to connect to an IMAP server using an existing SSH tunnel. This creates a new channel within the SSH tunnel, which can be a TCP or TLS connection, and is connected to a remote IMAP server through port forwarding. 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.Imap,
  Chilkat.Email,
  Chilkat.Socket;

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

procedure RunDemo;
var
  success: Boolean;
  tunnel: TSocket;
  sshHostname: string;
  sshPort: Integer;
  imap: TImap;
  msgCount: Integer;
  upperBound: Integer;
  email: TEmail;
  i: Integer;
  bUid: Boolean;

begin
  success := False;

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

  tunnel := TSocket.Create;

  sshHostname := 'sftp.example.com';
  sshPort := 22;

  //  Connect to an SSH server and establish the SSH tunnel:
  success := tunnel.SshOpenTunnel(sshHostname,sshPort);
  if (success = False) then
    begin
      WriteLn(tunnel.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 IMAP server, it is
  //  for authenticating with the SSH server, which is separate.
  success := tunnel.SshAuthenticatePw('mySshLogin','mySshPassword');
  if (success = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  //  OK, the SSH tunnel is setup.  Now open a channel within the tunnel.
  //  Once the channel is obtained, the Socket API may
  //  be used exactly the same as usual, except all communications
  //  are sent through the channel in the SSH tunnel.
  //  Any number of channels may be created from the same SSH tunnel.
  //  Multiple channels may coexist at the same time.

  imap := TImap.Create;

  //  Let the IMAP object also use the SSH tunnel
  success := imap.UseSshTunnel(tunnel);
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  Connect to an IMAP server via the already established SSH tunnel.
  //  Because the SSH tunnel has been previously setup,
  //  this does not establish a direct connection with the IMAP
  //  server.  It directs the SSH server to establish the connection.

  //  In this example, the IMAP server requires SSL/TLS.  The TLS connection
  //  will be enclosed within the SSH tunnel.
  imap.Ssl := True;
  imap.Port := 993;
  success := imap.Connect('imap.my-imap-server.com');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  Authenticate with the IMAP server via the SSH tunnel.
  success := imap.Login('myLogin','myPassword');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  Select an IMAP mailbox
  success := imap.SelectMailbox('Inbox');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  How many messages in Inbox?
  msgCount := imap.NumMessages;
  if (msgCount = 0) then
    begin
      WriteLn('No messages found.');
      Exit;
    end;

  upperBound := 10;
  if (msgCount < upperBound) then
    begin
      upperBound := msgCount;
    end;

  //  Download up to the 1st 10 messages.
  email := TEmail.Create;

  bUid := False;
  for i := 1 to upperBound do
    begin

      success := imap.FetchEmail(False,i,bUid,email);
      if (success = False) then
        begin
          WriteLn(imap.LastErrorText);
          Exit;
        end;

      WriteLn(email.From);
      WriteLn(email.Subject);

    end;

  //  Disconnect from the IMAP server.
  //  The SSH tunnel remains open.
  success := imap.Disconnect();
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  It is possible to re-use the existing SSH tunnel for the next connection:
  success := imap.Connect('imap.my-imap-server2.com');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

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

  //  This closes the SSH channel, which is the connection with the IMAP server.
  //  It does not close the SSH tunnel
  success := imap.Disconnect();
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  Finally, close the SSH tunnel.

  //  Note: If other objects are using the same SSH tunnel, the tunnel is not 
  //  actually closed.  It is only closed when the last object using the tunnel closes it.

  //  At this point, both the imap and tunnel objects have references to the internal
  //  SSH tunnel.  We need to close each.

  //  This call doesn't actually close the tunnel yet, because the tunnel object still
  //  holds an internal reference.
  success := imap.SshCloseTunnel();
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  This actually closes the SSH tunnel because it's the last object using it.
  success := tunnel.SshCloseTunnel();
  if (success = False) then
    begin
      WriteLn(tunnel.LastErrorText);
      Exit;
    end;

  WriteLn('IMAP pre-existing SSH tunnel example completed.');


  tunnel.Free;
  imap.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.