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

/*!
\page qthttpserver-logging.html
\title Qt HTTP Server Logging
\brief Shows how the QtHttpServer module logging can be configured.

The Qt HTTP Server logs using the \l {QLoggingCategory} {QLoggingCategory}
class. The logging categories starting with \c "qt.httpserver" are used by
the different parts of the Qt Http Server. These can be enabled and disabled
as described in \l{QLoggingCategory}.

To dynamically enable or disable what is being logged call
\l {QLoggingCategory::setFilterRules()}. A server can add a URL to change
the filter rules, by using the \l QHttpServer::route() function as shown below.

\code
#include <QCoreApplication>
#include <QHttpServer>
#include <QLoggingCategory>

int main(int argc, char** argv)
{
    QCoreApplication app(argc, argv);
    QHttpServer server;
    auto tcpserver = std::make_unique<QTcpServer>();
    if (!tcpserver->listen(QHostAddress::LocalHost, 8000) || !server.bind(tcpserver.get()))
        return -1;
    tcpserver.release();

    server.route("/loggingFilter", [] (const QHttpServerRequest &request) {
        QString filter;
        QTextStream result(&filter);
        for (auto pair : request.query().queryItems()) {
            if (!filter.isEmpty())
                result << "\n";
            result << pair.first << "=" << pair.second;
        }
        QLoggingCategory::setFilterRules(filter);
        return filter;
    });

    return app.exec();
}
\endcode

The filter rules can now be set using: \c
{"http://127.0.0.1:8000/loggingFilter?qt.httpserver=true&appname.access=true"}.
In this case all Qt HTTP Server logging will be enabled, and in addition the
hypothetical logging category \c{appname.access} is enabled.

\sa QLoggingCategory, QHttpServer
*/