Delphi DLL

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. Delphi DLL

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, Imap, Email, Socket;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
tunnel: HCkSocket;
sshHostname: PWideChar;
sshPort: Integer;
imap: HCkImap;
msgCount: Integer;
upperBound: Integer;
email: HCkEmail;
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 := CkSocket_Create();

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

// Connect to an SSH server and establish the SSH tunnel:
success := CkSocket_SshOpenTunnel(tunnel,sshHostname,sshPort);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnel));
    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 := CkSocket_SshAuthenticatePw(tunnel,'mySshLogin','mySshPassword');
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnel));
    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 := CkImap_Create();

// Let the IMAP object also use the SSH tunnel
success := CkImap_UseSshTunnel(imap,tunnel);
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    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.
CkImap_putSsl(imap,True);
CkImap_putPort(imap,993);
success := CkImap_Connect(imap,'imap.my-imap-server.com');
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// Authenticate with the IMAP server via the SSH tunnel.
success := CkImap_Login(imap,'myLogin','myPassword');
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// Select an IMAP mailbox
success := CkImap_SelectMailbox(imap,'Inbox');
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// How many messages in Inbox?
msgCount := CkImap_getNumMessages(imap);
if (msgCount = 0) then
  begin
    Memo1.Lines.Add('No messages found.');
    Exit;
  end;

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

// Download up to the 1st 10 messages.
email := CkEmail_Create();

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

    success := CkImap_FetchEmail(imap,False,i,bUid,email);
    if (success = False) then
      begin
        Memo1.Lines.Add(CkImap__lastErrorText(imap));
        Exit;
      end;

    Memo1.Lines.Add(CkEmail__from(email));
    Memo1.Lines.Add(CkEmail__subject(email));

  end;

// Disconnect from the IMAP server.
// The SSH tunnel remains open.
success := CkImap_Disconnect(imap);
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// It is possible to re-use the existing SSH tunnel for the next connection:
success := CkImap_Connect(imap,'imap.my-imap-server2.com');
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// Review the LastErrorText to see that the connection was made via the SSH tunnel:
Memo1.Lines.Add(CkImap__lastErrorText(imap));

// This closes the SSH channel, which is the connection with the IMAP server.
// It does not close the SSH tunnel
success := CkImap_Disconnect(imap);
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    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 := CkImap_SshCloseTunnel(imap);
if (success = False) then
  begin
    Memo1.Lines.Add(CkImap__lastErrorText(imap));
    Exit;
  end;

// This actually closes the SSH tunnel because it's the last object using it.
success := CkSocket_SshCloseTunnel(tunnel);
if (success = False) then
  begin
    Memo1.Lines.Add(CkSocket__lastErrorText(tunnel));
    Exit;
  end;

Memo1.Lines.Add('IMAP pre-existing SSH tunnel example completed.');

CkSocket_Dispose(tunnel);
CkImap_Dispose(imap);
CkEmail_Dispose(email);

end;