Pascal (Lazarus/Delphi)

Find a Label ID by Name

See more GMail REST API Examples

Lookup the ID of a GMail label by the label name. 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.Http,
  Chilkat.StringBuilder,
  Chilkat.JsonObject;

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

procedure RunDemo;
var
  success: Boolean;
  http: THttp;
  userId: string;
  url: string;
  sb: TStringBuilder;
  json: TJsonObject;
  jRecord: TJsonObject;

begin
  success := False;

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

  http := THttp.Create;
  http.AuthToken := 'GMAIL-ACCESS-TOKEN';

  userId := 'me';
  http.SetUrlVar('userId',userId);

  url := 'https://www.googleapis.com/gmail/v1/users/{$userId}/labels';

  //  Get the list of GMail labels as JSON.
  sb := TStringBuilder.Create;
  success := http.QuickGetSb(url,sb);
  if (success <> True) then
    begin
      WriteLn(http.LastErrorText);
      Exit;
    end;

  json := TJsonObject.Create;
  json.LoadSb(sb);
  json.EmitCompact := False;
  WriteLn(json.Emit());

  if (http.LastStatus <> 200) then
    begin
      WriteLn('Failed.');
      Exit;
    end;

  //  The JSON returned looks like this:
  //  {
  //    "labels": [
  //      {
  //        "id": "Label_5",
  //        "name": "QA",
  //        "messageListVisibility": "show",
  //        "labelListVisibility": "labelShow",
  //        "type": "user"
  //      },
  //      {
  //        "id": "Label_21",
  //        "name": "[Gmail]/testFolder",
  //        "type": "user"
  //      },
  //      {
  //        "id": "CATEGORY_PERSONAL",
  //        "name": "CATEGORY_PERSONAL",
  //        "type": "system"
  //      },
  //  	...

  //  The name of the label is generally known because it's what we visually see.
  //  The id is what we need to get.  Assuming the name is unique,
  //  find the JSON record having name=<desired name>
  //  For example...
  jRecord := json.FindRecord('labels','name','QA',False);
  if (json.LastMethodSuccess = True) then
    begin
      WriteLn('The id of QA is: ' + jRecord.StringOf('id'));
      jRecord.Free;
    end;

  jRecord := json.FindRecord('labels','name','[Gmail]/testFolder',False);
  if (json.LastMethodSuccess = True) then
    begin
      WriteLn('The id of [Gmail]/testFolder is: ' + jRecord.StringOf('id'));
      jRecord.Free;
    end;

  jRecord := json.FindRecord('labels','name','questions',False);
  if (json.LastMethodSuccess = True) then
    begin
      WriteLn('The id of questions is: ' + jRecord.StringOf('id'));
      jRecord.Free;
    end;

  //  Output:

  //  The id of QA is: Label_5
  //  The id of [Gmail]/testFolder is: Label_21
  //  The id of questions is: Label_43


  http.Free;
  sb.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.