POP3: Download Most Recent Email (method 2)

How to ready the N most recent email from a POP3 server.

The POP3 protocol does not provide the ability to request the most recent email, nor does it provide the ability to download email based on read/unread status or any other criteria. The design principle behind POP3 is that it is a temporary holding store for incoming email and email clients or other applications will transfer email from the POP3 server to a local persistent store where it will be managed. Therefore, POP3 does not provide sophisticated functionality (as opposed to IMAP which has the opposite design philosophy: that email is maintained and organized on the server).

This example shows one possible way to retrieve the N most recent emails from a POP3 server. It downloads the complete list of UIDLs and then downloads the last N into a bundle object. It assumes that the UIDLs will be returned by the POP3 server ordered by date such that the 1st email in the UIDL list is the oldest, and the last email is the newest.

Download Chilkat Email ActiveX for POP3 / SMTP

uses
    Windows, Messages, SysUtils, Variants, Classes, Graphics, Controls, Forms,
    Dialogs, StdCtrls,
    CHILKATMAILLib2_TLB,
    CHILKATUTILLib_TLB,
    OleCtrls;

...

procedure TForm1.Button1Click(Sender: TObject);
var
mailman: TChilkatMailMan2;
success: Integer;
saUidls: CHILKATUTILLib_TLB.ICkStringArray;
i: Integer;
n: Integer;
startIdx: Integer;
saUidls2: CHILKATUTILLib_TLB.ICkStringArray;
bundle: CHILKATMAILLib2_TLB.IChilkatEmailBundle2;
email: CHILKATMAILLib2_TLB.IChilkatEmail2;

begin
//  The mailman object is used for receiving (POP3)
//  and sending (SMTP) email.
mailman := TChilkatMailMan2.Create(Self);

//  Any string argument automatically begins the 30-day trial.
success := mailman.UnlockComponent('30-day trial');
if (success <> 1) then
  begin
    ShowMessage('Component unlock failed');

  end;

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

//  Set the POP3 login/password.
mailman.PopUsername := 'admin@chilkatsoft.com';
mailman.PopPassword := '****';

//  Get the complete list of UIDLs
saUidls := mailman.GetUidls() as CHILKATUTILLib_TLB.ICkStringArray;

if (saUidls = nil ) then
  begin
    ShowMessage(mailman.LastErrorText);

  end;

//  Get the 10 most recent UIDLs
//  The 1st email is the oldest, the last email is the newest
//  (usually)

n := saUidls.Count;
if (n > 10) then
  begin
    startIdx := n - 10;
  end
else
  begin
    startIdx := 0;
  end;

saUidls2 := TCkStringArray.Create(Self).ControlInterface;
for i := startIdx to n - 1 do
  begin
    saUidls2.Append(saUidls.GetString(i));
  end;

//  Download in full the 10 most recent emails:

bundle := mailman.FetchMultiple(saUidls2);
if (bundle = nil ) then
  begin
    ShowMessage(mailman.LastErrorText);

  end;

for i := 0 to bundle.MessageCount - 1 do
  begin
    email := bundle.GetEmail(i);
    Memo1.Lines.Add(email.From);
    Memo1.Lines.Add(email.Subject);
    Memo1.Lines.Add('----');

  end;

end;