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// Copyright (C) 2026 The Qt Company Ltd.
// SPDX-License-Identifier: LicenseRef-Qt-Commercial OR BSD-3-Clause
#include "httpserver.h"
#include <QHostAddress>
#include <QList>
#include <QTcpServer>
#include <QTcpSocket>
#include <optional>
namespace {
constexpr int maxRequestSize = 8 * 1024;
QByteArray makeHttpResponse(int statusCode, const char *reasonPhrase,
const QByteArray &mimeType, const QByteArray &body)
{
return QByteArray("HTTP/1.1 ") + QByteArray::number(statusCode) + ' ' + reasonPhrase + "\r\n"
+ "Content-Type: " + mimeType + "\r\n"
+ "Content-Length: " + QByteArray::number(body.size()) + "\r\n"
+ "Connection: close\r\n"
+ "\r\n" + body;
}
// Returns the request target (the path, without any query string) once the HTTP
// request line has fully arrived, or nullopt while it is still incomplete.
std::optional<QByteArray> tryParseRequestTarget(const QByteArray &request)
{
const int endOfLine = request.indexOf("\r\n");
if (endOfLine < 0)
return std::nullopt;
const QList<QByteArray> parts = request.left(endOfLine).split(' ');
if (parts.size() < 2)
return QByteArray();
QByteArray target = parts.at(1);
const int queryStart = target.indexOf('?');
if (queryStart >= 0)
target.truncate(queryStart);
return target;
}
} // namespace
HttpServer::HttpServer(QHash<QByteArray, HttpResource> routes, QObject *parent)
: QObject(parent)
, m_routes(std::move(routes))
, m_server(new QTcpServer(this))
{
connect(m_server, &QTcpServer::newConnection, this, [this]() {
while (QTcpSocket *socket = m_server->nextPendingConnection())
serveConnection(socket);
});
}
bool HttpServer::listen()
{
if (!m_server->listen(QHostAddress::LocalHost)) {
qWarning("Failed to start HTTP server: %s", qPrintable(m_server->errorString()));
return false;
}
return true;
}
quint16 HttpServer::port() const
{
return m_server->serverPort();
}
void HttpServer::serveConnection(QTcpSocket *socket)
{
connect(socket, &QTcpSocket::disconnected, socket, &QObject::deleteLater);
connect(socket, &QTcpSocket::readyRead, socket,
[this, socket, request = QByteArray()]() mutable {
if (socket->state() != QAbstractSocket::ConnectedState)
return;
request += socket->readAll();
const std::optional<QByteArray> target = tryParseRequestTarget(request);
if (!target) {
if (request.size() > maxRequestSize) {
qWarning("HTTP server: request line exceeded %d bytes; dropping connection",
maxRequestSize);
socket->disconnectFromHost();
}
return;
}
const auto route = m_routes.constFind(*target);
const auto response = route != m_routes.constEnd()
? makeHttpResponse(200, "OK", route->mimeType, route->body)
: makeHttpResponse(404, "Not Found", "text/plain", "Not Found\n");
socket->write(response);
socket->disconnectFromHost();
});
}