How to create a REST API with QtHttpServer

Current status of QtHttpServer

What is QtHttpServer

How does the REST API work

Implementing a REST API

Hello world

#include <QtCore>
#include <QtHttpServer>

int main(int argc, char **argv)
{
    QCoreApplication app(argc, argv);
    QHttpServer httpServer;

    const auto port = httpServer.listen(QHostAddress::Any);

    if (!port)
        return 0;

    qDebug() << QCoreApplication::translate("QHttpServerExample",
            "Running on http://127.0.0.1:%1/ (Press CTRL+C to quit)").arg(port);
    return app.exec(); 
} 

Define routes

GET route

httpServer.route("/myApi", QHttpServerRequest::Method::Get,
    [&myData](const QHttpServerRequest &request) {
        QJsonArray array = myData;
        return QHttpServerResponse(array);
    }
);

httpServer.route("/myApi/<arg>", QHttpServerRequest::Method::Get,
    [&myData](int id, const QHttpServerRequest &request) {
        QJsonObject myApiObject = myData.find(id);
        return QHttpServerResponse(myApiObject);
    }
);

POST route with authorization

bool authorize(const QHttpServerRequest &request)
{
    for (const auto &[key, value] : request.headers()) {
        if (key == “SECRET_KEY” && value == “SECRET_VALUE”)
            return true;
    }
    return false;
}

QJsonObject byteArrayToJsonObject(const QByteArray &arr)
{
    const auto json = QJsonDocument::fromJson(arr);
    return json.object();
}

httpServer.route("/myApi", QHttpServerRequest::Method::Post,
    [&myData](const QHttpServerRequest &request) {
        if (!authorize(request))
            return QHttpServerResponse(QHttpServerResponder::StatusCode::Unauthorized);

        const QJsonObject newObject = byteArrayToJsonObject(request.body());
        myData.insert(newObject);
        return QHttpServerResponse(newObject, QHttpServerResponder::StatusCode::Created);
    }
);

Hosting files

httpServer.route("/myApi/img/<arg>-image.jpg", QHttpServerRequest::Method::Get,
    [](int imageId, const QHttpServerRequest &) {
        return QHttpServerResponse::fromFile(QString(":/assets/img/%1-image.jpg")
                .arg(imageId));
    }
);