webfinger.cpp

QString extractUserName(const QString& path) {
  const auto parts = path.split("/", QString::SkipEmptyParts);

  if (path.startsWith("/@")) {
    return parts.first();
  }
  
  if (path.startsWith("/users")) {
    return parts.last();
  } 
  
  return QString();
}

QUrl generateWebFingerUrlFromUrl(const QUrl& url) {
   const auto domain = QString("%1://%2").arg(url.scheme()).arg(url.host());
   const auto userName = extractUserName(url.path());

    if (!userName.isEmpty()) {
        return QUrl(QString("%1/.well-known/webfinger?resource=acct:%2@%3").arg(domain).arg(userName).arg(url.host()));
    }

    return QUrl();
}

WebFinger extractWebFingerFromData(const QByteArray& data) {
    const QJsonDocument respJson(QJsonDocument::fromBinaryData(data));
    WebFinger webFinger;
    webFinger.subject = respJson.object().find("subject").value().toString();
    webFinger.aliases = respJson.object().find("aliases").value().toVariant().toStringList();

    return webFinger;
}

// TODO: Fetch JSON from server.
// TODO: Extract into body.
void WebFinger::discoverByUrl(const QUrl& url, function<void(WebFinger)> func) {
   const QUrl webFingerUrl = generateWebFingerUrlFromUrl(url);

    if (!url.isEmpty()) {
        QSharedPointer<QNetworkAccessManager> manager(new QNetworkAccessManager());
        QObject::connect(manager.get(), &QNetworkAccessManager::finished, QApplication::instance(), [=](QNetworkReply* reply){
            const WebFinger webFinger = extractWebFingerFromData(reply->readAll());
            func(webFinger);
        });

        QNetworkRequest request(webFingerUrl);
        request.setRawHeader("Accept", "application/ld+json");
        request.setHeader(QNetworkRequest::UserAgentHeader, "ActivityDesk/0.0.1 (https://activitydesk.black.af)");
        manager->get(request);
    } else {
        WebFinger webFinger;
        func(webFinger);
    }
}