(MFC) Google Drive Refresh Access Token

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

Chilkat C/C++ Library Downloads MS Visual C/C++ Libs

See Also: Using MFC CString in Chilkat

#include <CkJsonObject.h>
#include <CkOAuth2.h>
#include <CkFileAccess.h>

void ChilkatSample(void)
    {
    CkString strOut;

    // 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"
    // }

    CkJsonObject json;
    const char *tokenFilePath = "qa_data/tokens/googleDrive.json";
    json.LoadFile(tokenFilePath);

    CkOAuth2 oauth2;
    oauth2.put_AccessToken(json.stringOf("access_token"));
    oauth2.put_RefreshToken(json.stringOf("refresh_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) {
        strOut.append(oauth2.lastErrorText());
        strOut.append("\r\n");
        SetDlgItemText(IDC_EDIT1,strOut.getUnicode());
        return;
    }

    strOut.append(oauth2.accessTokenResponse());
    strOut.append("\r\n");

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

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

    strOut.append("Access Token Refreshed!");
    strOut.append("\r\n");


    SetDlgItemText(IDC_EDIT1,strOut.getUnicode());

    }