Add standalone C++/Qt example which opens HTML client in a browser.

This example shows how to use the (currently quite ugly) raw C++ API
to setup a webchannel without using QML at all. The HTML client is then
handled by the users default browser.

The example itself shows a simple chat between the HTML client and the
C++/Qt server, with a line edit for input and a text edit showing the
chat history.

Change-Id: I8baf14efb9d0c5f5880d99710cf6317fe9b887b9
Reviewed-by: Zeno Albisser <zeno.albisser@digia.com>

2 files changed, 21 insertions, 0 deletions

diff --git a/src/webchannel/qmetaobjectpublisher.cpp b/src/webchannel/qmetaobjectpublisher.cpp
index c141fb2..fcf809a 100644
--- a/src/webchannel/qmetaobjectpublisher.cpp
+++ b/src/webchannel/qmetaobjectpublisher.cpp
@@ -54,6 +54,7 @@
 #include <QDebug>
 #include <QPointer>
 #include <QEvent>
+#include <QJsonDocument>
 
 namespace {
 const QString KEY_SIGNALS = QStringLiteral("signals");
@@ -647,6 +648,17 @@ bool QMetaObjectPublisher::handleRequest(const QJsonObject &message)
     return false;
 }
 
+void QMetaObjectPublisher::handleRawMessage(const QString &message)
+{
+    QJsonParseError error;
+    const QJsonDocument doc = QJsonDocument::fromJson(message.toUtf8(), &error);
+    if (error.error) {
+        qWarning() << "Could not parse raw input message as JSON: " << error.errorString() << "Message was: " << message;
+    } else if (doc.isObject() && !handleRequest(doc.object())) {
+        qWarning() << "Could not handle raw message as meta object request: " << message;
+    }
+}
+
 QWebChannel *QMetaObjectPublisher::webChannel() const
 {
     return d->webChannel;
diff --git a/src/webchannel/qmetaobjectpublisher.h b/src/webchannel/qmetaobjectpublisher.h
index da733b2..684be1d 100644
--- a/src/webchannel/qmetaobjectpublisher.h
+++ b/src/webchannel/qmetaobjectpublisher.h
@@ -103,6 +103,15 @@ signals:
     void webChannelChanged(QWebChannel *channel);
     void blockUpdatesChanged(bool block);
 
+public slots:
+    /**
+     * Helper slot which you can connect directly to WebChannel's rawMessageReceived signal.
+     *
+     * This slot then tries to parse the message as JSON and if it succeeds, calls handleRequest
+     * with the obtained JSON object.
+     */
+    void handleRawMessage(const QString &message);
+
 protected:
     void timerEvent(QTimerEvent *) Q_DECL_OVERRIDE;