(C#) Google Drive Refresh Access Token

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

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

bool 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"
// }

Chilkat.JsonObject json = new Chilkat.JsonObject();
string tokenFilePath = "qa_data/tokens/googleDrive.json";
json.LoadFile(tokenFilePath);

Chilkat.OAuth2 oauth2 = new Chilkat.OAuth2();
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 != true) {
    Debug.WriteLine(oauth2.LastErrorText);
    return;
}

Debug.WriteLine(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);

Chilkat.FileAccess fac = new Chilkat.FileAccess();
fac.WriteEntireTextFile(tokenFilePath,json.Emit(),"utf-8",false);

Debug.WriteLine("Access Token Refreshed!");