wasm: add echo_server test TCP server

Test server for in-browser TCP usage.

Pick-to: 6.4
Change-Id: Ia1a29c0e14a6d2ee8075ce202c9f6998a3ccc4c9
Reviewed-by: Lorn Potter <lorn.potter@gmail.com>

tests/manual/wasm/network/echo_server/CMakeLists.txt

@@ -0,0 +1,14 @@
+project(echo_server)
+cmake_minimum_required(VERSION 3.19)
+
+find_package(Qt6 COMPONENTS Core)
+find_package(Qt6 COMPONENTS network)
+
+qt_add_executable(echo_server
+    main.cpp
+)
+
+target_link_libraries(echo_server PUBLIC
+    Qt::Core
+    Qt::Network
+)

tests/manual/wasm/network/echo_server/main.cpp

@@ -0,0 +1,127 @@
+/****************************************************************************
+**
+** Copyright (C) 2021 The Qt Company Ltd.
+** Contact: https://www.qt.io/licensing/
+**
+** This file is part of the examples of the Qt Toolkit.
+**
+** $QT_BEGIN_LICENSE:BSD$
+** Commercial License Usage
+** Licensees holding valid commercial Qt licenses may use this file in
+** accordance with the commercial license agreement provided with the
+** Software or, alternatively, in accordance with the terms contained in
+** a written agreement between you and The Qt Company. For licensing terms
+** and conditions see https://www.qt.io/terms-conditions. For further
+** information use the contact form at https://www.qt.io/contact-us.
+**
+** BSD License Usage
+** Alternatively, you may use this file under the terms of the BSD license
+** as follows:
+**
+** "Redistribution and use in source and binary forms, with or without
+** modification, are permitted provided that the following conditions are
+** met:
+**   * Redistributions of source code must retain the above copyright
+**     notice, this list of conditions and the following disclaimer.
+**   * Redistributions in binary form must reproduce the above copyright
+**     notice, this list of conditions and the following disclaimer in
+**     the documentation and/or other materials provided with the
+**     distribution.
+**   * Neither the name of The Qt Company Ltd nor the names of its
+**     contributors may be used to endorse or promote products derived
+**     from this software without specific prior written permission.
+**
+**
+** THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
+** "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
+** LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
+** A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
+** OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
+** SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
+** LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
+** DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
+** THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
+** (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
+** OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE."
+**
+** $QT_END_LICENSE$
+**
+****************************************************************************/
+
+#include <QtCore>
+#include <QtNetwork>
+
+const int timeout = 60 * 1000;
+
+int main(int argc, char **argv)
+{
+    QCoreApplication app(argc, argv);
+
+    QTcpServer server;
+    QObject::connect(&server, &QTcpServer::newConnection, [&server](){
+        qDebug() << "new connection";
+
+        QByteArray *receiveBuffer = new QByteArray();
+
+        QTcpSocket *socket = server.nextPendingConnection();
+        QObject::connect(socket, &QIODevice::readyRead, [socket, receiveBuffer](){
+
+            // This implements a very simple command protocol, where the server
+            // processes a stream of commands delimited by ';', and then performs
+            // an action in reply. The supported commands with actions are:
+            //
+            //  echo:<message>;  writes the received <message> back
+            //  close;           closes the socket
+            //
+
+            // We might receive multiple or partial commands; read all available data
+            // and then scan the buffer for complete commands.
+            QByteArray newData = socket->readAll();
+            *receiveBuffer += newData;
+
+            int pos = receiveBuffer->indexOf(";");
+            while (pos != -1) {
+                QByteArray command = receiveBuffer->left(pos);
+                receiveBuffer->remove(0, pos + 1);
+                pos = receiveBuffer->indexOf(";");
+
+                if (command.startsWith("echo")) {
+                    // Echo expects echo:<message>
+                    QList<QByteArray> parts = command.split(':');
+                    QByteArray reply = parts.last() + ';';
+                    qDebug() << "Command: echo:" << parts.last();
+                    socket->write(reply);
+                    socket->flush();
+
+                } else if (command.startsWith("close")) {
+                    qDebug() << "Command: close";
+                    socket->write("bye!;");
+                    socket->flush();
+                    socket->close();
+                    break;
+                } else {
+                    qDebug() << "Unknown command:" << command;
+                }
+            }
+        });
+
+        QObject::connect(socket, &QAbstractSocket::disconnected, [socket, receiveBuffer](){
+            delete receiveBuffer;
+            socket->deleteLater();
+        });
+    });
+
+    // This is example is intended to be used together with WebSockify on
+    // the server and acts as a counterpart to the client examples which
+    // run in the browser. (This example does not run in the browser).
+
+    qDebug() << "\nStarting echo server at port 1516. You should now start the"
+             << "\nWebSockify forwarding server, and then connect from one of"
+             << "\nthe client examples."
+             << "\n  websockify 1515 localhost:1516";
+
+    server.listen(QHostAddress::Any, 1516);
+
+    return app.exec();
+}
+