Java

Google Drive Refresh Access Token

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

import com.chilkatsoft.*;

public class ChilkatExample {

  static {
    try {
        System.loadLibrary("chilkat");
    } catch (UnsatisfiedLinkError e) {
      System.err.println("Native code library failed to load.\n" + e);
      System.exit(1);
    }
  }

  public static void main(String argv[])
  {
    boolean success = false;

    success = true;

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

    //  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"
    //  }

    CkJsonObject json = new CkJsonObject();
    String tokenFilePath = "qa_data/tokens/googleDrive.json";
    json.LoadFile(tokenFilePath);

    CkOAuth2 oauth2 = new CkOAuth2();
    oauth2.put_AccessToken(json.stringOf("access_token"));
    oauth2.put_RefreshToken(json.stringOf("refresh_token"));

    CkRest rest = new CkRest();

    //  Connect using TLS.
    boolean bAutoReconnect = true;
    success = rest.Connect("www.googleapis.com",443,true,bAutoReconnect);

    //  Provide the authentication credentials (i.e. the access token)
    rest.SetAuthOAuth2(oauth2);

    //  We'll test with a simple request to empty trash.
    //  If our access token expired, we'll get a 401 response..
    String jsonResponse = rest.fullRequestNoBody("DELETE","/drive/v3/files/trash");
    if (rest.get_LastMethodSuccess() != true) {
        System.out.println(rest.lastErrorText());
        return;
        }

    //  If the access token expired, we'll get a 401 response status with this response body:
    //  {
    //   "error": {
    //    "errors": [
    //     {
    //      "domain": "global",
    //      "reason": "authError",
    //      "message": "Invalid Credentials",
    //      "locationType": "header",
    //      "location": "Authorization"
    //     }
    //    ],
    //    "code": 401,
    //    "message": "Invalid Credentials"
    //   }
    //  }
    if (rest.get_ResponseStatusCode() == 401) {

        System.out.println("Refreshing access token...");

        oauth2.put_AuthorizationEndpoint("https://accounts.google.com/o/oauth2/v2/auth");
        oauth2.put_TokenEndpoint("https://www.googleapis.com/oauth2/v4/token");

        //   Replace these with actual values.
        oauth2.put_ClientId("GOOGLE-CLIENT-ID");
        oauth2.put_ClientSecret("GOOGLE-CLIENT-SECRET");
        oauth2.put_Scope("https://www.googleapis.com/auth/drive");

        //  Use OAuth2 to refresh the access token.
        success = oauth2.RefreshAccessToken();
        if (success != true) {
            System.out.println(oauth2.lastErrorText());
            return;
            }

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

        CkFileAccess fac = new CkFileAccess();
        fac.WriteEntireTextFile(tokenFilePath,json.emit(),"utf-8",false);

        System.out.println("Access Token Refreshed!");

        //  Retry the request with the new access token..
        jsonResponse = rest.fullRequestNoBody("DELETE","/drive/v3/files/trash");
        if (rest.get_LastMethodSuccess() != true) {
            System.out.println(rest.lastErrorText());
            return;
            }

        }

    //  A successful response will have a status code equal to 204 and the response body is empty.
    //  (If not successful, then there should be a JSON response body with information..)
    if (rest.get_ResponseStatusCode() != 204) {
        System.out.println("response status code = " + rest.get_ResponseStatusCode());
        System.out.println("response status text = " + rest.responseStatusText());
        System.out.println("response header: " + rest.responseHeader());
        System.out.println("response JSON: " + jsonResponse);
        return;
        }

    System.out.println("Trash Emptied!");
  }
}