- Qt 6.6
- Qt HTTP Server
- Qt HTTP Server Examples
- Simple HTTP Server
- Qt 6.6.0 Reference Documentation

# Simple HTTP Server

     // Copyright (C) 2018 The Qt Company Ltd.
     // SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause

     #include <QHttpServer>
     #include <QHttpServerResponse>

     #if QT_CONFIG(ssl)
     #  include <QSslCertificate>
     #  include <QSslKey>
     #endif

     #include <QCoreApplication>
     #include <QFile>
     #include <QJsonObject>
     #include <QString>

     using namespace Qt::StringLiterals;

     static inline QString host(const QHttpServerRequest &request)
     {
         return QString::fromLatin1(request.value("Host"));
     }

     int main(int argc, char *argv[])
     {
         QCoreApplication app(argc, argv);

         QHttpServer httpServer;
         httpServer.route("/", []() {
             return "Hello world";
         });

         httpServer.route("/query", [] (const QHttpServerRequest &request) {
             return host(request) + u"/query/"_s;
         });

         httpServer.route("/query/", [] (qint32 id, const QHttpServerRequest &request) {
             return u"%1/query/%2"_s.arg(host(request)).arg(id);
         });

         httpServer.route("/query/<arg>/log", [] (qint32 id, const QHttpServerRequest &request) {
             return u"%1/query/%2/log"_s.arg(host(request)).arg(id);
         });

         httpServer.route("/query/<arg>/log/", [] (qint32 id, float threshold,
                                                   const QHttpServerRequest &request) {
             return u"%1/query/%2/log/%3"_s.arg(host(request)).arg(id).arg(threshold);
         });

         httpServer.route("/user/", [] (const qint32 id) {
             return u"User "_s + QString::number(id);
         });

         httpServer.route("/user/<arg>/detail", [] (const qint32 id) {
             return u"User %1 detail"_s.arg(id);
         });

         httpServer.route("/user/<arg>/detail/", [] (const qint32 id, const qint32 year) {
             return u"User %1 detail year - %2"_s.arg(id).arg(year);
         });

         httpServer.route("/json/", [] {
             return QJsonObject{
                 {
                     {"key1", "1"},
                     {"key2", "2"},
                     {"key3", "3"}
                 }
             };
         });

         httpServer.route("/assets/<arg>", [] (const QUrl &url) {
             return QHttpServerResponse::fromFile(u":/assets/"_s + url.path());
         });

         httpServer.route("/remote_address", [](const QHttpServerRequest &request) {
             return request.remoteAddress().toString();
         });

         // Basic authentication example (RFC 7617)
         httpServer.route("/auth", [](const QHttpServerRequest &request) {
             auto auth = request.value("authorization").simplified();

             if (auth.size() > 6 && auth.first(6).toLower() == "basic ") {
                 auto token = auth.sliced(6);
                 auto userPass = QByteArray::fromBase64(token);

                 if (auto colon = userPass.indexOf(':'); colon > 0) {
                     auto userId = userPass.first(colon);
                     auto password = userPass.sliced(colon + 1);

                     if (userId == "Aladdin" && password == "open sesame")
                         return QHttpServerResponse("text/plain", "Success\n");
                 }
             }
             QHttpServerResponse response("text/plain", "Authentication required\n",
                                          QHttpServerResponse::StatusCode::Unauthorized);
             response.setHeader("WWW-Authenticate", R"(Basic realm="Simple example", charset="UTF-8")");
             return response;
         });

         httpServer.afterRequest([](QHttpServerResponse &&resp) {
             resp.setHeader("Server", "Qt HTTP Server");
             return std::move(resp);
         });

         const auto port = httpServer.listen(QHostAddress::Any);
         if (!port) {
             qWarning() << QCoreApplication::translate("QHttpServerExample",
                                                       "Server failed to listen on a port.");
             return -1;
         }

     #if QT_CONFIG(ssl)
         const auto sslCertificateChain =
                 QSslCertificate::fromPath(QStringLiteral(":/assets/certificate.crt"));
         if (sslCertificateChain.empty()) {
             qWarning() << QCoreApplication::translate("QHttpServerExample",
                                                       "Couldn't retrieve SSL certificate from file.");
             return -1;
         }
         QFile privateKeyFile(QStringLiteral(":/assets/private.key"));
         if (!privateKeyFile.open(QIODevice::ReadOnly)) {
             qWarning() << QCoreApplication::translate("QHttpServerExample",
                                                       "Couldn't open file for reading: %1")
                           .arg(privateKeyFile.errorString());
             return -1;
         }
         httpServer.sslSetup(sslCertificateChain.front(), QSslKey(&privateKeyFile, QSsl::Rsa));
         privateKeyFile.close();

         const auto sslPort = httpServer.listen(QHostAddress::Any);
         if (!sslPort) {
             qWarning() << QCoreApplication::translate("QHttpServerExample",
                                                       "Server failed to listen on a port.");
             return -1;
         }

         qInfo().noquote()
             << QCoreApplication::translate("QHttpServerExample",
                                            "Running on http://127.0.0.1:%1/ and "
                                            "https://127.0.0.1:%2/ (Press CTRL+C to quit)")
                .arg(port).arg(sslPort);
     #else
         qInfo().noquote()
             << QCoreApplication::translate("QHttpServerExample",
                                            "Running on http://127.0.0.1:%1/"
                                            "(Press CTRL+C to quit)").arg(port);
     #endif
         return app.exec();
     }