(Delphi ActiveX) Google Drive Refresh Access Token

Demonstrates how to automatically refresh the access token when it expires.

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
success: Integer;
json: TChilkatJsonObject;
tokenFilePath: WideString;
oauth2: TChilkatOAuth2;
fac: TCkFileAccess;

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

success := 1;

// This example uses a previously obtained access token having permission for the 
// Google Drive scope.

// The access token (and refresh token) was previously saved to a JSON file with this format:
// See Get Google Drive OAuth2 Access Token

// {
//   "access_token": "ya29.Gls-BsdxTWuenChv ... yzVIrXikkLxu5T6dy4I6GjADFardoz4Lruw",
//   "expires_in": 3600,
//   "refresh_token": "1/tMBJ ... 27D-Hk6rpQYBA",
//   "scope": "https://www.googleapis.com/auth/drive",
//   "token_type": "Bearer"
// }

json := TChilkatJsonObject.Create(Self);
tokenFilePath := 'qa_data/tokens/googleDrive.json';
json.LoadFile(tokenFilePath);

oauth2 := TChilkatOAuth2.Create(Self);
oauth2.AccessToken := json.StringOf('access_token');
oauth2.RefreshToken := json.StringOf('refresh_token');

oauth2.AuthorizationEndpoint := 'https://accounts.google.com/o/oauth2/v2/auth';
oauth2.TokenEndpoint := 'https://www.googleapis.com/oauth2/v4/token';

//  Replace these with actual values.
oauth2.ClientId := 'GOOGLE-CLIENT-ID';
oauth2.ClientSecret := 'GOOGLE-CLIENT-SECRET';
oauth2.Scope := 'https://www.googleapis.com/auth/drive';

// Use OAuth2 to refresh the access token.
success := oauth2.RefreshAccessToken();
if (success <> 1) then
  begin
    Memo1.Lines.Add(oauth2.LastErrorText);
    Exit;
  end;

Memo1.Lines.Add(oauth2.AccessTokenResponse);

// Save the new access token to our JSON file (so we can refresh it again when needed).
json.UpdateString('access_token',oauth2.AccessToken);

fac := TCkFileAccess.Create(Self);
fac.WriteEntireTextFile(tokenFilePath,json.Emit(),'utf-8',0);

Memo1.Lines.Add('Access Token Refreshed!');
end;