chore: add simple Qt example that uses libwaku (#3310)

.gitignore

@@ -72,3 +72,7 @@ coverage_html_report/
 **/rln_tree/
 **/certs/
 
+# simple qt example
+.qmake.stash
+main-qt
+waku_handler.moc.cpp

examples/qt/Makefile

@@ -0,0 +1,26 @@
+
+## Has been compiled with Qt 5.15.2
+
+## If change the main.qml, the qmake should be called
+## This may be needed in Ubuntu: sudo apt install qtdeclarative5-dev qtquickcontrols2-5-dev
+
+CXX = g++
+CXXFLAGS = -g3 -fpermissive -fPIC `pkg-config --cflags Qt5Core Qt5Gui Qt5Qml Qt5Quick`
+LDFLAGS = `pkg-config --libs Qt5Core Qt5Gui Qt5Qml Qt5Quick` -lwaku -L../../build/
+MOC = moc
+
+TARGET = main-qt
+SRC = main_qt.cpp
+MOC_SRC = waku_handler.moc.cpp
+HEADERS = waku_handler.h
+
+all: $(TARGET)
+
+$(MOC_SRC): $(HEADERS)
+	$(MOC) $< -o $@
+
+$(TARGET): $(SRC) $(MOC_SRC)
+	$(CXX) $(CXXFLAGS) -o $(TARGET) $(SRC) $(MOC_SRC) $(LDFLAGS)
+
+clean:
+	rm -f $(TARGET) $(MOC_SRC)

examples/qt/main.qml

@@ -0,0 +1,64 @@
+import QtQuick 2.15
+import QtQuick.Controls 2.15
+
+ApplicationWindow {
+    visible: true
+    width: 400
+    height: 300
+    title: "Hello, World!"
+
+    Column {
+        anchors.centerIn: parent
+        spacing: 20
+
+        Label {
+            text: "Hello, World!"
+            font.pixelSize: 24
+            horizontalAlignment: Text.AlignHCenter
+        }
+    }
+
+    Rectangle {
+        width: parent.width
+        height: 60
+        anchors.bottom: parent.bottom
+        color: "transparent"
+
+        Row {
+            anchors.centerIn: parent
+            spacing: 30
+
+            Button {
+                text: "Start Waku Node"
+                width: 150
+                height: 40
+                font.pixelSize: 16
+                MouseArea {
+                    anchors.fill: parent
+                    cursorShape: Qt.PointingHandCursor
+                    onClicked: wakuHandler.start()
+                }
+                background: Rectangle {
+                    color: "#2196F3"
+                    radius: 10
+                }
+            }
+
+            Button {
+                text: "Stop Waku Node"
+                width: 150
+                height: 40
+                font.pixelSize: 16
+                MouseArea {
+                    anchors.fill: parent
+                    cursorShape: Qt.PointingHandCursor
+                    onClicked: wakuHandler.stop()
+                }
+                background: Rectangle {
+                    color: "#F44336"
+                    radius: 10
+                }
+            }
+        }
+    }
+}

examples/qt/main_qt.cpp

@@ -0,0 +1,46 @@
+#include <QGuiApplication>
+#include <QQmlApplicationEngine>
+#include <QQmlContext>
+
+#include "waku_handler.h"
+
+void event_handler(int callerRet, const char* msg, size_t len, void* userData) {
+    printf("Receiving message %s\n", msg);
+}
+
+int main(int argc, char *argv[]) {
+    QGuiApplication app(argc, argv);
+    QQmlApplicationEngine engine;
+
+    WakuHandler wakuHandler;
+    void* userData = nullptr;
+
+    QString jsonConfig = R"(
+        {
+            "tcpPort": 60000,
+            "relay": true,
+            "logLevel": "TRACE",
+            "discv5Discovery": true,
+            "discv5BootstrapNodes": [
+                "enr:-QESuEB4Dchgjn7gfAvwB00CxTA-nGiyk-aALI-H4dYSZD3rUk7bZHmP8d2U6xDiQ2vZffpo45Jp7zKNdnwDUx6g4o6XAYJpZIJ2NIJpcIRA4VDAim11bHRpYWRkcnO4XAArNiZub2RlLTAxLmRvLWFtczMud2FrdS5zYW5kYm94LnN0YXR1cy5pbQZ2XwAtNiZub2RlLTAxLmRvLWFtczMud2FrdS5zYW5kYm94LnN0YXR1cy5pbQYfQN4DgnJzkwABCAAAAAEAAgADAAQABQAGAAeJc2VjcDI1NmsxoQOvD3S3jUNICsrOILlmhENiWAMmMVlAl6-Q8wRB7hidY4N0Y3CCdl-DdWRwgiMohXdha3UyDw",
+                "enr:-QEkuEBIkb8q8_mrorHndoXH9t5N6ZfD-jehQCrYeoJDPHqT0l0wyaONa2-piRQsi3oVKAzDShDVeoQhy0uwN1xbZfPZAYJpZIJ2NIJpcIQiQlleim11bHRpYWRkcnO4bgA0Ni9ub2RlLTAxLmdjLXVzLWNlbnRyYWwxLWEud2FrdS5zYW5kYm94LnN0YXR1cy5pbQZ2XwA2Ni9ub2RlLTAxLmdjLXVzLWNlbnRyYWwxLWEud2FrdS5zYW5kYm94LnN0YXR1cy5pbQYfQN4DgnJzkwABCAAAAAEAAgADAAQABQAGAAeJc2VjcDI1NmsxoQKnGt-GSgqPSf3IAPM7bFgTlpczpMZZLF3geeoNNsxzSoN0Y3CCdl-DdWRwgiMohXdha3UyDw"
+            ],
+            "discv5UdpPort": 9999,
+            "dnsDiscovery": true,
+            "dnsDiscoveryUrl": "enrtree://AOGYWMBYOUIMOENHXCHILPKY3ZRFEULMFI4DOM442QSZ73TT2A7VI@test.waku.nodes.status.im",
+            "dnsDiscoveryNameServers": ["8.8.8.8", "1.0.0.1"]
+        }
+        )";
+
+    wakuHandler.initialize(jsonConfig, event_handler, userData);
+
+    engine.rootContext()->setContextProperty("wakuHandler", &wakuHandler);
+
+    engine.load(QUrl::fromLocalFile("main.qml"));
+    
+    if (engine.rootObjects().isEmpty())
+        return -1;
+
+    return app.exec();
+}
+

examples/qt/qt.pro

@@ -0,0 +1,18 @@
+######################################################################
+# Automatically generated by qmake (3.1) Thu Feb 27 21:42:11 2025
+######################################################################
+
+TEMPLATE = app
+TARGET = qt
+INCLUDEPATH += .
+
+# You can make your code fail to compile if you use deprecated APIs.
+# In order to do so, uncomment the following line.
+# Please consult the documentation of the deprecated API in order to know
+# how to port your code away from it.
+# You can also select to disable deprecated APIs only up to a certain version of Qt.
+#DEFINES += QT_DISABLE_DEPRECATED_BEFORE=0x060000    # disables all the APIs deprecated before Qt 6.0.0
+
+# Input
+HEADERS += waku_handler.h
+SOURCES += main_qt.cpp waku_hand.moc.cpp waku_handler.moc.cpp

examples/qt/waku_handler.h

@@ -0,0 +1,56 @@
+#include <QObject>
+#include <QDebug>
+#include <QString>
+
+#include "../../library/libwaku.h"
+
+class WakuHandler : public QObject {
+    Q_OBJECT
+private:
+    static void event_handler(int callerRet, const char* msg, size_t len, void* userData) {
+        printf("Receiving message %s\n", msg);
+    }
+
+    static void on_event_received(int callerRet, const char* msg, size_t len, void* userData) {
+        if (callerRet == RET_ERR) {
+            printf("Error: %s\n", msg);
+            exit(1);
+        }
+        else if (callerRet == RET_OK) {
+            printf("Receiving event: %s\n", msg);
+        }
+    }
+
+public:
+    WakuHandler() : QObject(), ctx(nullptr) {}
+
+    void initialize(const QString& jsonConfig, WakuCallBack event_handler, void* userData) {
+        ctx = waku_new(jsonConfig.toUtf8().constData(), WakuCallBack(event_handler), userData);
+
+        waku_set_event_callback(ctx, on_event_received, userData);
+        qDebug() << "Waku context initialized, ready to start.";
+    }
+
+    Q_INVOKABLE void start() {
+        if (ctx) {
+            waku_start(ctx, event_handler, nullptr);
+            qDebug() << "Waku start called with event_handler and userData.";
+        } else {
+            qDebug() << "Context is not initialized in start.";
+        }
+    }
+
+    Q_INVOKABLE void stop() {
+        if (ctx) {
+            waku_stop(ctx, event_handler, nullptr);
+            qDebug() << "Waku stop called with event_handler and userData.";
+        } else {
+            qDebug() << "Context is not initialized in stop.";
+        }
+    }
+
+    virtual ~WakuHandler() {}
+
+private:
+    void* ctx;
+};