Delphi DLL

Find a Label ID by Name

See more GMail REST API Examples

Lookup the ID of a GMail label by the label name. Delphi DLL

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

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
http: HCkHttp;
userId: PWideChar;
url: PWideChar;
sb: HCkStringBuilder;
json: HCkJsonObject;
jRecord: HCkJsonObject;

begin
success := False;

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

http := CkHttp_Create();
CkHttp_putAuthToken(http,'GMAIL-ACCESS-TOKEN');

userId := 'me';
CkHttp_SetUrlVar(http,'userId',userId);

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

// Get the list of GMail labels as JSON.
sb := CkStringBuilder_Create();
success := CkHttp_QuickGetSb(http,url,sb);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkHttp__lastErrorText(http));
    Exit;
  end;

json := CkJsonObject_Create();
CkJsonObject_LoadSb(json,sb);
CkJsonObject_putEmitCompact(json,False);
Memo1.Lines.Add(CkJsonObject__emit(json));

if (CkHttp_getLastStatus(http) <> 200) then
  begin
    Memo1.Lines.Add('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 := CkJsonObject_FindRecord(json,'labels','name','QA',False);
if (CkJsonObject_getLastMethodSuccess(json) = True) then
  begin
    Memo1.Lines.Add('The id of QA is: ' + CkJsonObject__stringOf(jRecord,'id'));
    CkJsonObject_Dispose(jRecord);
  end;

jRecord := CkJsonObject_FindRecord(json,'labels','name','[Gmail]/testFolder',False);
if (CkJsonObject_getLastMethodSuccess(json) = True) then
  begin
    Memo1.Lines.Add('The id of [Gmail]/testFolder is: ' + CkJsonObject__stringOf(jRecord,'id'));
    CkJsonObject_Dispose(jRecord);
  end;

jRecord := CkJsonObject_FindRecord(json,'labels','name','questions',False);
if (CkJsonObject_getLastMethodSuccess(json) = True) then
  begin
    Memo1.Lines.Add('The id of questions is: ' + CkJsonObject__stringOf(jRecord,'id'));
    CkJsonObject_Dispose(jRecord);
  end;

// Output:

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

CkHttp_Dispose(http);
CkStringBuilder_Dispose(sb);
CkJsonObject_Dispose(json);

end;