(Delphi DLL) Google Drive Refresh Access Token

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

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

uses
    Winapi.Windows, Winapi.Messages, System.SysUtils, System.Variants, System.Classes, Vcl.Graphics,
    Vcl.Controls, Vcl.Forms, Vcl.Dialogs, Vcl.StdCtrls, FileAccess, OAuth2, JsonObject;

...

procedure TForm1.Button1Click(Sender: TObject);
var
success: Boolean;
json: HCkJsonObject;
tokenFilePath: PWideChar;
oauth2: HCkOAuth2;
fac: HCkFileAccess;

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

success := True;

// 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 := CkJsonObject_Create();
tokenFilePath := 'qa_data/tokens/googleDrive.json';
CkJsonObject_LoadFile(json,tokenFilePath);

oauth2 := CkOAuth2_Create();
CkOAuth2_putAccessToken(oauth2,CkJsonObject__stringOf(json,'access_token'));
CkOAuth2_putRefreshToken(oauth2,CkJsonObject__stringOf(json,'refresh_token'));

CkOAuth2_putAuthorizationEndpoint(oauth2,'https://accounts.google.com/o/oauth2/v2/auth');
CkOAuth2_putTokenEndpoint(oauth2,'https://www.googleapis.com/oauth2/v4/token');

//  Replace these with actual values.
CkOAuth2_putClientId(oauth2,'GOOGLE-CLIENT-ID');
CkOAuth2_putClientSecret(oauth2,'GOOGLE-CLIENT-SECRET');
CkOAuth2_putScope(oauth2,'https://www.googleapis.com/auth/drive');

// Use OAuth2 to refresh the access token.
success := CkOAuth2_RefreshAccessToken(oauth2);
if (success <> True) then
  begin
    Memo1.Lines.Add(CkOAuth2__lastErrorText(oauth2));
    Exit;
  end;

Memo1.Lines.Add(CkOAuth2__accessTokenResponse(oauth2));

// Save the new access token to our JSON file (so we can refresh it again when needed).
CkJsonObject_UpdateString(json,'access_token',CkOAuth2__accessToken(oauth2));

fac := CkFileAccess_Create();
CkFileAccess_WriteEntireTextFile(fac,tokenFilePath,CkJsonObject__emit(json),'utf-8',False);

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

CkJsonObject_Dispose(json);
CkOAuth2_Dispose(oauth2);
CkFileAccess_Dispose(fac);

end;