// Copyright (C) 2022 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR GFDL-1.3-no-invariants-only

/*!
    \page qthttpserver-index.html
    \since 6.4
    \title Qt HTTP Server
    \brief Provides a lightweight server implementing the HTTP protocol.

    Qt HTTP Server supports building HTTP server functionality into an application.
    Common use cases are exposing the application's functionality through
    REST APIs, or making devices in a trusted environment configurable also via HTTP.
    The limitations are described in \l{Limitations and Security}.

    \section1 Overview

    Qt HTTP Server provides building blocks for embedding a lightweight HTTP server
    based on \l{RFC 2616} and \l{RFC 9113} in an application. There are classes for
    the messages sent and received, and for the various parts of an HTTP server.

    The QHttpServer class has a \l{QHttpServer::}{route()} function to bind
    callables to different incoming URLs. These callables can take as arguments
    an \l{QHttpServerRouter::addConverter}{extensible} collection of different
    copyable types that are parsed from the URL. Types supported are most numeric
    types, QString, QByteArray, and QUrl. Optionally the callables can also take
    QHttpServerRequest and QHttpServerResponder objects as arguments. The
    QHttpServerRequest class contains all the information of an incoming request,
    and is needed to get the \l{QHttpServerRequest::}{body()} from a POST HTTP
    request. The callables either return a QHttpServerResponse object or respond
    using the QHttpServerResponder argument. The QHttpServerResponse class
    contains a complete response and has numerous constructors for different types,
    while the QHttpServerResponder has various methods for writing back to the
    client.

    The QHttpServer class also has an \l{QHttpServer::}{addAfterRequestHandler()}
    function to process a QHttpServerResponse further, and a
    \l{QHttpServer::}{setMissingHandler()} function to override the default
    behavior of returning \c{404 Not Found} when no routes are matched. From
    the QAbstractHttpServer class it inherits a \l{QAbstractHttpServer::}{bind()}
    function to bind to a listening QTcpServer, QSslServer, or QLocalServer.

    An HTTP server can also be created by subclassing the QAbstractHttpServer
    class and overriding the \l{QAbstractHttpServer::}{handleRequest()} and
    \l{QAbstractHttpServer::}{missingHandler()} functions.

    Runtime logging can be configured as described \l{qthttpserver-logging.html}{here}.

    \section1 Limitations and Security

    Qt HTTP Server does not have many of the more advanced features and optimizations
    that general-purpose HTTP servers have. It also has not seen
    the same scrutiny regarding various attack vectors over the network.
    Use Qt HTTP Server, therefore, only for local connections
    or in a trusted network, and do not expose the ports to the internet.

    You can add HTTPS support as a basic security measure, though. If Qt is compiled
    with support for TLS, you can bind the HTTP server to a QSslServer object,
    providing Transport Layer Security handling.

    The \l{QSslSocket::SupportedFeature::ServerSideAlpn} feature from the
    active TLS backend is needed for HTTP/2 support. To check if a backend
    supports this, use \l{QSslSocket::isFeatureSupported}.

    \section1 Using the Module

    Using a Qt module requires linking against the module library, either
    directly or through other dependencies. Several build tools have dedicated
    support for this, including CMake and qmake.

    \section2 Building with CMake

    Use the \c find_package() command to locate the needed module components in
    the Qt6 package:

    \badcode
    find_package(Qt6 REQUIRED COMPONENTS HttpServer)
    target_link_libraries(mytarget PRIVATE Qt6::HttpServer)
    \endcode

    See also the \l{Build with CMake} overview.

    \section2 Building with qmake

    To configure the module for building with qmake, add the module as a value
    of the QT variable in the project's .pro file:

    \badcode
    QT += httpserver
    \endcode

    \section1 Licenses

    Qt HTTP Server is available under commercial licenses from \l{The Qt Company}.
    In addition, it is available under the \l {GNU General Public License, version 3}.
    See \l{Qt Licensing} for further details.

    \section1 Reference
    \list
    \li \l{Qt HTTP Server Logging}
    \li \l{Qt HTTP Server C++ Classes}{C++ Classes}
    \endlist

    \section1 Examples

    The module provides the following \l{Qt HTTP Server Examples}{Examples} as a guide to using
    the API.
*/