How to set redirect_uri using QOAuth2AuthorizationCodeFlow and QOAuthHttpServerReplyHandler

Question

For OAuth 2.0 using QT's networkauth and the new QOAuth2AuthorizationCodeFlow object, how can I set the redirect_uri? My code is below. It results in the following authenticate url being sent:

QOAuth2AuthorizationCodeFlow::buildAuthenticateUrl: https://accounts.google.com/o/oauth2/auth?client_id=123-abc.apps.googleusercontent.com&redirect_uri=http://localhost:65535/cb&response_type=code&scope=email&state=iEIYn5sN

The setting of redirect_uri to "http://localhost", results in an Error 400 redirect_uri_mismatch from google which is obviously expecting the actual redirect hostname to be provided.

GoogleGateway::GoogleGateway() {

auto google = new QOAuth2AuthorizationCodeFlow;
google->setScope("email");

this->connect(google, &QOAuth2AuthorizationCodeFlow::authorizeWithBrowser, &QDesktopServices::openUrl);

QString val;
QFile file;
file.setFileName("/home/me/client_secret.json");
file.open(QIODevice::ReadOnly | QIODevice::Text);
val = file.readAll();
file.close();

QJsonDocument document = QJsonDocument::fromJson(val.toUtf8());
QJsonObject object = document.object();
const auto settingsObject = object["web"].toObject();
const QUrl authUri(settingsObject["auth_uri"].toString());
const auto clientId = settingsObject["client_id"].toString();
const QUrl tokenUri(settingsObject["token_uri"].toString());
const auto clientSecret(settingsObject["client_secret"].toString());
const auto redirectUris = settingsObject["redirect_uris"].toArray();
const QUrl redirectUri(redirectUris[0].toString());
const auto port = static_cast<quint16>(redirectUri.port());

google->setAuthorizationUrl(authUri);
google->setClientIdentifier(clientId);
google->setAccessTokenUrl(tokenUri);
google->setClientIdentifierSharedKey(clientSecret);

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

google->grant();
}

To set the redirect_uri, I've tried replacing:

auto replyHandler = new QOAuthHttpServerReplyHandler(port, this);

with

QHostAddress hostaddress = QHostAddress(quint32(1233...));
auto replyHandler = new QOAuthHttpServerReplyHandler(hostaddress, port, this);

with no change in the result.

Have also tried inserting:

replyHandler->setProperty("redirect_uri", "http://abc.xyz.com:65535/cb");

also with no change in the result.

In Qt/5.8/Src/qtnetworkauth/src/oauth/qoauthhttpserverreplyhandler.cpp, we see that the callback address looks suspiciously hard-coded:

QString QOAuthHttpServerReplyHandler::callback() const
{
    Q_D(const QOAuthHttpServerReplyHandler);

    Q_ASSERT(d->httpServer.isListening());
    const QUrl url(QString::fromLatin1("http://localhost:%1/cb").arg(d->httpServer.serverPort()));
    return url.toString(QUrl::EncodeDelimiters);
}

This callback() is in turn used in Qt/5.8/Src/qtnetworkauth/src/oauth/qoauth2authorizationcodeflow.cpp to set the redirectUri value:

QUrl QOAuth2AuthorizationCodeFlow::buildAuthenticateUrl(const QVariantMap &parameters)
{
    Q_D(QOAuth2AuthorizationCodeFlow);
    using Key = QAbstractOAuth2Private::OAuth2KeyString;

    if (d->state.isEmpty())
        setState(QAbstractOAuth2Private::generateRandomState());
    Q_ASSERT(!d->state.isEmpty());
    const QString state = d->state;

    QVariantMap p(parameters);
    QUrl url(d->authorizationUrl);
    p.insert(Key::responseType, responseType());
    p.insert(Key::clientIdentifier, d->clientCredentials.first);
    p.insert(Key::redirectUri, callback());
    p.insert(Key::scope, d->scope);
    p.insert(Key::state, state);
    if (d->modifyParametersFunction)
        d->modifyParametersFunction(Stage::RequestingAuthorization, &p);
    url.setQuery(d->createQuery(p));
    connect(d->replyHandler.data(), &QAbstractOAuthReplyHandler::callbackReceived, this,
            &QOAuth2AuthorizationCodeFlow::authorizationCallbackReceived, Qt::UniqueConnection);
    setStatus(QAbstractOAuth::Status::NotAuthenticated);
    qDebug("QOAuth2AuthorizationCodeFlow::buildAuthenticateUrl: %s", qPrintable(url.toString()));
    return url;
}

Is this a bug?

Answer 1

I just solved this by subclassing MyOAuthHttpServerReplyHandler and overriding the definition of callback() to return the URI I wanted.