Google OAuth gives error when trying to exchange token

[Kiovtorov]

Hi, I can't seem to make the google oauth 2.0 connect with QNetworkAccessManager

#include "googlegateway.hpp"
#include <QObject>
#include <QJsonDocument>
#include <QJsonObject>
#include <QJsonArray>
#include <QString>
#include <QFile>
#include <QDir>
#include <QUrl>
#include <QOAuthHttpServerReplyHandler>
#include <QDesktopServices>
#include <QEventLoop>


GoogleGateway::GoogleGateway(QObject* parent) : QObject(parent)
{
    google = new QOAuth2AuthorizationCodeFlow;

    // Create a new network access manager and assign it to the OAuth object
    QNetworkAccessManager* networkManager = new QNetworkAccessManager(this);
    google->setNetworkAccessManager(networkManager);  // Assign the manager to google

    google->setScope("profile email openid");

    QObject::connect(google, &QOAuth2AuthorizationCodeFlow::authorizeWithBrowser,
                     &QDesktopServices::openUrl);

    google->setClientIdentifier("user.apps.googleusercontent.com");
    google->setClientIdentifierSharedKey("key");
    google->setAuthorizationUrl(QUrl("https://accounts.google.com/o/oauth2/auth"));
    google->setAccessTokenUrl(QUrl("https://oauth2.googleapis.com/token"));

    // Initialize the reply handler with a specific port, if necessary
    replyHandler = new QOAuthHttpServerReplyHandler(1234, this);
    google->setReplyHandler(replyHandler);

    // Grant access and handle token reception
    google->grant();
    QObject::connect(google, &QOAuth2AuthorizationCodeFlow::granted, [this] {
        qDebug() << "Token granted:" << google->token();
    });

    // Optionally connect the network manager's signals for further debugging
    QObject::connect(networkManager, &QNetworkAccessManager::finished, this, [](QNetworkReply* reply) {
        qDebug() << "Request URL:" << reply->url().toString();
        qDebug() << "Request status code:" << reply->attribute(QNetworkRequest::HttpStatusCodeAttribute).toInt();
        qDebug() << "Raw headers:" << reply->rawHeaderList();

        if (reply->error() != QNetworkReply::NoError) {
            qDebug() << "Request failed with error:" << reply->errorString();
            qDebug() << "Response:" << reply->readAll();  // This logs the server response body
        } else {
            qDebug() << "Request succeeded. Response:" << reply->readAll();
        }
    });

}

Here is my output:

qt.networkauth.replyhandler: Invalid request: /favicon.ico
Request URL: "https://oauth2.googleapis.com/token"
Request status code: 400
Raw headers: QList("date", "pragma", "cache-control", "expires", "content-type", "vary", "server", "x-xss-protection", "x-frame-options", "x-content-type-options", "alt-svc", "accept-ranges")
Request failed with error: "Error transferring https://oauth2.googleapis.com/token - server replied: "
Response: "{\n  \"error\": \"invalid_grant\",\n  \"error_description\": \"Malformed auth code.\"\n}"
qt.networkauth.oauth2: Token request failed: "Error transferring https://oauth2.googleapis.com/token - server replied: "

I will leave a screenshot of the google console

[Kiovtorov]

I am using Qt 6.7.2 version

[Kiovtorov]

I managed to fix it using google drive.

#include "googleauth.h"

GoogleAuth::GoogleAuth(QObject *parent) : QObject(parent)
{
    this->google = new QOAuth2AuthorizationCodeFlow(this);

    // Set Scope or Permissions required from Google
    this->google->setScope("email profile openid https://www.googleapis.com/auth/drive.readonly");

    connect(this->google, &QOAuth2AuthorizationCodeFlow::authorizeWithBrowser, [=](QUrl url) {
        QUrlQuery query(url);
        query.addQueryItem("prompt", "consent");      // Param required to get data everytime
        query.addQueryItem("access_type", "offline"); // Needed for Refresh Token (as AccessToken expires shortly)
        url.setQuery(query);
        QDesktopServices::openUrl(url);
    });

    // OAuth URLs and Client Identifier (from Google Console)
    this->google->setAuthorizationUrl(QUrl("https://accounts.google.com/o/oauth2/auth"));
    this->google->setAccessTokenUrl(QUrl("https://oauth2.googleapis.com/token"));
    this->google->setClientIdentifier("user.apps.googleusercontent.com");
    this->google->setClientIdentifierSharedKey("client_secret");

    auto replyHandler = new QOAuthHttpServerReplyHandler(5476, this);
    this->google->setReplyHandler(replyHandler);

    connect(this->google, &QOAuth2AuthorizationCodeFlow::granted, [=]() {
        qDebug() << __FUNCTION__ << __LINE__ << "Access Granted!";

        // Fetching user info from OpenID Connect endpoint
        QUrl userInfoUrl("https://www.googleapis.com/oauth2/v3/userinfo");
        auto reply = this->google->get(userInfoUrl);

        connect(reply, &QNetworkReply::finished, [reply]() {
            if (reply->error() == QNetworkReply::NoError) {
                qDebug() << "User Info: " << reply->readAll();
            } else {
                qDebug() << "Error fetching user info: " << reply->errorString();
            }
            reply->deleteLater();
        });
    });
}

// Call this function to prompt authentication
// and receive data from Google

void GoogleAuth::click()
{
    this->google->grant();
}

Absolutely no idea why it needs google drive. I would like it to work without it so if anyone has an idea what could be done. Let me know. Thanks