(Delphi ActiveX) IMAP Search with THREAD Semantics

Demonstrates how to search an IMAP mailbox and return message numbers grouped together in parent/child relationships based on which messages are replies to others.

Note: This example requires Chilkat v9.5.0.77 or greater.

Chilkat for Delphi Downloads Chilkat ActiveX DLL for Delphi Chilkat non-ActiveX DLL for Delphi * The examples here use the ActiveX DLL.

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
imap: TChilkatImap;
success: Integer;
json: IChilkatJsonObject;
numThreads: Integer;
arr: IChilkatJsonArray;
threadSize: Integer;
i: Integer;
subArr: IChilkatJsonArray;

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

imap := TChilkatImap.Create(Self);

// Connect to your IMAP server and authenticate..
imap.Ssl := 1;
imap.Port := 993;
success := imap.Connect('imap.mail.us-west-2.awsapps.com');
if (success <> 1) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

success := imap.Login('myLogin','myPassword');
if (success <> 1) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

// Select a mailbox
success := imap.SelectMailbox('Inbox');
if (success <> 1) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

// Search for all message having the letter 'a' somewhere in the Subject,
// and return the messages as JSON.
json := imap.ThreadCmd('REFERENCES','UTF-8','SUBJECT a',1);
if (imap.LastMethodSuccess = 0) then
  begin
    Memo1.Lines.Add(imap.LastErrorText);
    Exit;
  end;

// The IMAP server will return a raw response with a format such as this:  (2)(3 6 (4 23)(44 7 96))

// In tree form, it's like this:
// 
//             -- 2
//             -- 3
//                 \-- 6
//                    |-- 4
//                    |      \-- 23
//                    |
//                    |-- 44
//                               \-- 7
//                                       \-- 96
// 

// It means there are 2 main threads returned, but the 2nd thread splits into two sub-threads.
// In total, we can think of it as 3 threads -- 2 main threads (with no parents) and one sub-thread w/ a parent.
// 
// - The 1st thread contains the message 2, and has no parent thread.
// - The 2nd thread contains the messages 3, 6, 4, 23, and has no parent thread.
// - The 3rd thread contains the messages 44, 7, 96 and the parent thread is message 6.
// 

// (Yes, this is all highly confusing...)

// Chilkat will return the above sample response as JSON that looks like this:

// {
//   "threads": [
//     [2],
//     [3, 6, [4, 23], [44, 7, 96]]
//   ]
// }
// 

// Use this online tool to generate parsing code from sample JSON: 
// Generate Parsing Code from JSON
// In this case, the online tool can help you get a feel for how to write the JSON parsing code..

numThreads := json.SizeOfArray('threads');
Memo1.Lines.Add('The total number of top-level threads is ' + IntToStr(numThreads));

// Let's say we wanted to get the messages in the thread 3, 6, 4, 23.
// We always follow the 1st branch to the bottom, ignoring the other branches.
// For example, if we had  [3, 5, [4, 23, [55, 56, 57], [68, 69]], [44, 7, 96]]
// then the thread would be 3, 5, 4, 43, 55, 56, 57

// For testing, let's substitute the response from the IMAP server with this sample:
json.Load('{"threads": [[2], [3, 5, [4, 23, [55, 56, 57], [68, 69]], [44, 7, 96]]]}');

// Begin with the 2nd top-level thread, which is at index 1.
Memo1.Lines.Add('Following the 2nd top level thread...');
arr := json.ArrayOf('threads[1]');
threadSize := arr.Size;
i := 0;
while i < threadSize do
  begin
    // Do we have an array or integer at this position?
    if (arr.TypeAt(i) = 4) then
      begin
        // This is a sub-array.
        subArr := arr.ArrayAt(i);

        // Follow the sub-array starting at the 1st position..
        arr := subArr;
        i := 0;
        threadSize := arr.Size;
      end
    else
      begin
        // Must be a single integer.
        Memo1.Lines.Add(IntToStr(arr.IntAt(i)));
        i := i + 1;
      end;
  end;

// The output is:
// 
// Following the 2nd top level thread...
// 3
// 5
// 4
// 23
// 55
// 56
// 57
end;