Pascal (Lazarus/Delphi)

Get IMAP Message Threads as JSON

Demonstrates the Chilkat Imap.QueryThread method, which sends the IMAP THREAD command for the selected mailbox and returns the thread hierarchy as JSON. The first argument is the threading algorithm (commonly REFERENCES or ORDEREDSUBJECT), the second is IMAP search criteria, and the third (bUid) selects UID vs sequence-number identifiers. The returned JSON has a top-level threads array whose nested arrays encode parent/child relationships. This example threads all messages in the Inbox.

Tip: JSON parsing code for this result can be generated at Chilkat Tools.

Background: "Conversation view" in a mail client — grouping a message with its replies and follow-ups — is exactly what the IMAP THREAD extension provides, computed on the server. REFERENCES threads by the References/In-Reply-To headers (the accurate way), while ORDEREDSUBJECT groups by subject. Not all servers support THREAD, so check HasCapability for it first.

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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.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  imap: TImap;
  json: TJsonObject;

begin
  success := False;

  //  Demonstrates the Imap.QueryThread method, which sends the IMAP THREAD command for the
  //  selected mailbox and returns the thread hierarchy as JSON.  The 1st argument is the
  //  threading algorithm (such as REFERENCES or ORDEREDSUBJECT), the 2nd is IMAP search
  //  criteria, and the 3rd (bUid) selects UID vs sequence-number identifiers.

  imap := TImap.Create;

  imap.Ssl := True;
  imap.Port := 993;

  success := imap.Connect('imap.example.com');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;
  success := imap.Login('user@example.com','myPassword');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  success := imap.SelectMailbox('Inbox');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  //  Group all messages into threads using the REFERENCES algorithm, returning UIDs.
  json := TJsonObject.Create;
  success := imap.QueryThread('REFERENCES','ALL',True,json);
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  json.EmitCompact := False;
  WriteLn(json.Emit());

  //  JSON parsing code for this result can be generated at Chilkat's online tool:
  //  https://tools.chilkat.io/jsonParse

  success := imap.Disconnect();
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;


  imap.Free;
  json.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.