Pascal (Lazarus/Delphi)

IMAP Search with THREAD Semantics

See more IMAP Examples

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. 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.JsonArray,
  Chilkat.Imap,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  imap: TImap;
  json: TJsonObject;
  numThreads: Integer;
  arr: TJsonArray;
  threadSize: Integer;
  i: Integer;
  subArr: TJsonArray;

begin
  success := False;

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

  imap := TImap.Create;

  //  Connect to your IMAP server and authenticate..
  imap.Ssl := True;
  imap.Port := 993;
  success := imap.Connect('imap.mail.us-west-2.awsapps.com');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

  success := imap.Login('myLogin','myPassword');
  if (success = False) then
    begin
      WriteLn(imap.LastErrorText);
      Exit;
    end;

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

  //  Search for all message having the letter 'a' somewhere in the Subject,
  //  and return the messages as JSON.
  json := TJsonObject.Create;
  success := imap.QueryThread('REFERENCES','SUBJECT a',True,json);
  if (success = False) then
    begin
      WriteLn(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');
  WriteLn('The total number of top-level threads is ' + 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.
  WriteLn('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);
          arr.Free;
          //  Follow the sub-array starting at the 1st position..
          arr := subArr;
          i := 0;
          threadSize := arr.Size;
        end
      else
        begin
          //  Must be a single integer.
          WriteLn(arr.IntAt(i));
          i := i + 1;
        end;
    end;

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


  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.