Update MQTT api a bit to be more flexible

libnymea-core/hardware/network/mqtt/mqttchannelimplementation.cpp

@@ -52,9 +52,9 @@ quint16 MqttChannelImplementation::serverPort() const
     return m_serverPort;
 }
 
-QString MqttChannelImplementation::topicPrefix() const
+QStringList MqttChannelImplementation::topicPrefixList() const
 {
-    return m_topicPrefix;
+    return m_topicPrefixList;
 }
 
 void MqttChannelImplementation::publish(const QString &topic, const QByteArray &payload)

libnymea-core/hardware/network/mqtt/mqttchannelimplementation.h

@@ -36,7 +36,7 @@ public:
     QString password() const override;
     QHostAddress serverAddress() const override;
     quint16 serverPort() const override;
-    QString topicPrefix() const override;
+    QStringList topicPrefixList() const override;
 
     void publish(const QString &topic, const QByteArray &payload) override;
 
@@ -49,7 +49,7 @@ private:
     QString m_password;
     QHostAddress m_serverAddress;
     quint16 m_serverPort;
-    QString m_topicPrefix;
+    QStringList m_topicPrefixList;
 
     friend class MqttProviderImplementation;
 };

libnymea-core/hardware/network/mqtt/mqttproviderimplementation.cpp

@@ -37,18 +37,23 @@ MqttProviderImplementation::MqttProviderImplementation(MqttBroker *broker, QObje
     connect(broker, &MqttBroker::publishReceived, this, &MqttProviderImplementation::onPublishReceived);
 }
 
-MqttChannel *MqttProviderImplementation::createChannel(const DeviceId &deviceId, const QHostAddress &clientAddress)
+MqttChannel *MqttProviderImplementation::createChannel(const QString &clientId, const QHostAddress &clientAddress, const QStringList &topicPrefixList)
 {
     if (m_broker->configurations().isEmpty()) {
-        qCWarning(dcMqtt) << "MQTT broker not running. Cannot create a channel for device" << deviceId;
+        qCWarning(dcMqtt) << "MQTT broker not running. Cannot create a channel for device" << clientId;
         return nullptr;
     }
 
     MqttChannelImplementation* channel = new MqttChannelImplementation();
-    channel->m_clientId = deviceId.toString().remove(QRegExp("[{}-]"));
+    channel->m_clientId = clientId;
     channel->m_username = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
     channel->m_password = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
-    channel->m_topicPrefix = channel->m_clientId;
+    if (!topicPrefixList.isEmpty()) {
+        channel->m_topicPrefixList = topicPrefixList;
+    } else {
+        QString defaultTopicPrefix = channel->m_clientId;
+        channel->m_topicPrefixList.append(defaultTopicPrefix);
+    }
 
 
     foreach (const QNetworkInterface &interface, QNetworkInterface::allInterfaces()) {
@@ -80,8 +85,10 @@ MqttChannel *MqttProviderImplementation::createChannel(const DeviceId &deviceId,
     policy.clientId = channel->clientId();
     policy.username = channel->username();
     policy.password = channel->password();
-    policy.allowedPublishTopicFilters.append(QString("%1/#").arg(channel->m_topicPrefix));
+    foreach (const QString &topicPrefix, channel->m_topicPrefixList) {
-    policy.allowedSubscribeTopicFilters.append(QString("%1/#").arg(channel->m_topicPrefix));
+        policy.allowedPublishTopicFilters.append(QString("%1/#").arg(topicPrefix));
+        policy.allowedSubscribeTopicFilters.append(QString("%1/#").arg(topicPrefix));
+    }
     m_broker->updatePolicy(policy);
 
     return channel;
@@ -99,7 +106,7 @@ void MqttProviderImplementation::releaseChannel(MqttChannel *channel)
     delete channel;
 }
 
-MqttClient *MqttProviderImplementation::createInternalClient(const DeviceId &deviceId)
+MqttClient *MqttProviderImplementation::createInternalClient(const QString &clientId)
 {
 
     ServerConfiguration preferredConfig;
@@ -117,7 +124,6 @@ MqttClient *MqttProviderImplementation::createInternalClient(const DeviceId &dev
         return nullptr;
     }
 
-    QString clientId = deviceId.toString().remove(QRegExp("[{}-]"));
     MqttPolicy policy;
     policy.clientId = clientId;
     policy.username = QUuid::createUuid().toString().remove(QRegExp("[{}-]"));
@@ -189,9 +195,16 @@ void MqttProviderImplementation::onPublishReceived(const QString &clientId, cons
 void MqttProviderImplementation::onPluginPublished(const QString &topic, const QByteArray &payload)
 {
     MqttChannelImplementation *channel = static_cast<MqttChannelImplementation*>(sender());
-    if (!topic.startsWith(channel->topicPrefix())) {
+    bool found = false;
+    foreach (const QString &topicPrefix, channel->topicPrefixList()) {
+        if (topicPrefix.startsWith(topicPrefix)) {
+            found = true;
+            break;
+        }
+
+    }
+    if (!found) {
         qCWarning(dcMqtt) << "Attempt to publish to MQTT channel for client" << channel->clientId() << "but topic is not within allowed topic prefix. Discarding message.";
-        return;
     }
     m_broker->publish(topic, payload);
 }

libnymea-core/hardware/network/mqtt/mqttproviderimplementation.h

@@ -34,10 +34,10 @@ class MqttProviderImplementation : public MqttProvider
 public:
     explicit MqttProviderImplementation(MqttBroker *broker, QObject *parent = nullptr);
 
-    MqttChannel* createChannel(const DeviceId &deviceId, const QHostAddress &clientAddress) override;
+    MqttChannel* createChannel(const QString &clientId, const QHostAddress &clientAddress, const QStringList &topicPrefixList = QStringList()) override;
     void releaseChannel(MqttChannel* channel) override;
 
-    MqttClient* createInternalClient(const DeviceId &deviceId) override;
+    MqttClient* createInternalClient(const QString &clientId) override;
 
     bool available() const override;
     bool enabled() const override;

libnymea/network/mqtt/mqttchannel.h

@@ -38,7 +38,7 @@ public:
     virtual QString password() const = 0;
     virtual QHostAddress serverAddress() const = 0;
     virtual quint16 serverPort() const = 0;
-    virtual QString topicPrefix() const = 0;
+    virtual QStringList topicPrefixList() const = 0;
 
     virtual void publish(const QString &topic, const QByteArray &payload) = 0;
 

libnymea/network/mqtt/mqttprovider.cpp

@@ -146,11 +146,20 @@
     \sa HardwareResource, HardwareManager::mqttProvider()
 */
 
-/*! \fn MqttChannel *MqttProvider::createChannel(const DeviceId &deviceId, const QHostAddress &clientAddress);
+/*! \fn MqttChannel *MqttProvider::createChannel(const QString &clientId, const QHostAddress &clientAddress, const QString &topicPrefix);
     Creates a new MQTT channel on the internal broker. The returned channel will have the required details for the
-    client device to connect to the broker. A temporaray clientId/user/password combination will be created and
+    client device to connect to the broker. A temporaray user/password combination will be created and
     clients connecting to the broker with those credentials will have access to subscribe and post to # within the
-    given topic prefix.
+    given \a topicPrefixList.
+
+    \a clientId must be unique within the system or the channel creation will fail. If a mqtt client allows to configure the
+    clientId, using it's deviceId is likely a good idea.
+
+    \a topicPrefixList will be used to generate the policy for this MQTT client by appending "/#" to it. This will allow the
+    client to publish and subscribe to topics within "<topicPrefix>/#". See The MQTT specification on topic filters for more details.
+    It is good practice to isolate clients as much as possible the topics should be as restrictive as possible to avoid devices
+    snooping in on other things on the MQTT broker. If no topicPrefix is provided, a default of "<clientId>" Id is generated,
+    resulting in a policy of "<clientId>/#". At this point it is not allowed for plugins to publish/subscribe to # or $ topics.
 
     \sa releaseChannel(MqttChannel *channel)
 */

libnymea/network/mqtt/mqttprovider.h

@@ -38,10 +38,10 @@ class MqttProvider : public HardwareResource
 public:
     explicit MqttProvider(QObject *parent = nullptr);
 
-    virtual MqttChannel* createChannel(const DeviceId &deviceId, const QHostAddress &clientAddress) = 0;
+    virtual MqttChannel* createChannel(const QString &clientId, const QHostAddress &clientAddress, const QStringList &topicPrefixList = QStringList()) = 0;
     virtual void releaseChannel(MqttChannel *channel) = 0;
 
-    virtual MqttClient* createInternalClient(const DeviceId &deviceId) = 0;
+    virtual MqttClient* createInternalClient(const QString &clientId) = 0;
 };
 
 #endif // MQTTPROVIDER_H