[mqtt] Add missing broker connection configuration parameters (#13303)

Allows to configure the following broker connection configuration parameters:

* Protocol: TCP (default), WEBSOCKETS
* MQTT Version: V3 (default), V5
* Hostname Validation: true (default), false

The defaults are chosen to remain backwards compatible.

Signed-off-by: Wouter Born <github@maindrain.net>

bundles/org.openhab.binding.mqtt/README.md

@@ -28,6 +28,9 @@ Required configuration parameters are:
 
 Additionally the following parameters can be set:
 
+* __hostnameValidated__: Validate hostname from certificate against server hostname for secure connection. Defaults to true.
+* __protocol__:  The protocol used for communicating with the broker (TCP, WEBSOCKETS). Defaults to TCP.
+* __mqttVersion__: The MQTT version used for communicating with the broker (V3, V5). Defaults to V3.
 * __qos__: Quality of Service. Can be 0, 1 or 2. Please read the MQTT specification for details. Defaults to 0.
 * __clientID__: Use a fixed client ID. Defaults to empty which means a user ID is generated for this connection.
 

bundles/org.openhab.binding.mqtt/src/main/java/org/openhab/binding/mqtt/handler/BrokerHandler.java

@@ -200,8 +200,8 @@ public class BrokerHandler extends AbstractBrokerHandler implements PinnedCallba
             throw new IllegalArgumentException("Host is empty!");
         }
 
-        final MqttBrokerConnection connection = new MqttBrokerConnection(host, config.port, config.secure,
+        final MqttBrokerConnection connection = new MqttBrokerConnection(config.protocol, config.mqttVersion, host,
-                config.clientID);
+                config.port, config.secure, config.hostnameValidated, config.clientID);
 
         final String username = config.username;
         final String password = config.password;

bundles/org.openhab.binding.mqtt/src/main/resources/OH-INF/i18n/mqtt.properties

@@ -26,6 +26,8 @@ thing-type.config.mqtt.broker.enableDiscovery.label = Enable Discovery
 thing-type.config.mqtt.broker.enableDiscovery.description = If set to true enables this broker for all discovery services.
 thing-type.config.mqtt.broker.host.label = Broker Hostname/IP
 thing-type.config.mqtt.broker.host.description = The IP/Hostname of the MQTT broker
+thing-type.config.mqtt.broker.hostnameValidated.label = Hostname Validated
+thing-type.config.mqtt.broker.hostnameValidated.description = Validate hostname from certificate against server hostname for secure connection.
 thing-type.config.mqtt.broker.keepAlive.label = Heartbeat
 thing-type.config.mqtt.broker.keepAlive.description = Keep alive / heartbeat timer in s. It can take up to this time to determine if a server connection is lost. A lower value may keep the broker unnecessarily busy for no or little additional value.
 thing-type.config.mqtt.broker.lwtMessage.label = Last Will Message
@@ -39,10 +41,18 @@ thing-type.config.mqtt.broker.lwtRetain.label = Last Will Retain
 thing-type.config.mqtt.broker.lwtRetain.description = True if last Will should be retained (defaults to false)
 thing-type.config.mqtt.broker.lwtTopic.label = Last Will Topic
 thing-type.config.mqtt.broker.lwtTopic.description = Defaults to empty and therefore disables the last will.
+thing-type.config.mqtt.broker.mqttVersion.label = MQTT Version
+thing-type.config.mqtt.broker.mqttVersion.description = The MQTT version used for communicating with the broker.
+thing-type.config.mqtt.broker.mqttVersion.option.V3 = Version 3
+thing-type.config.mqtt.broker.mqttVersion.option.V5 = Version 5
 thing-type.config.mqtt.broker.password.label = Password
 thing-type.config.mqtt.broker.password.description = The MQTT password
 thing-type.config.mqtt.broker.port.label = Broker Port
 thing-type.config.mqtt.broker.port.description = The port is optional, if none is provided, the typical ports 1883 and 8883 (SSL) are used.
+thing-type.config.mqtt.broker.protocol.label = Protocol
+thing-type.config.mqtt.broker.protocol.description = The protocol used for communicating with the broker.
+thing-type.config.mqtt.broker.protocol.option.TCP = TCP
+thing-type.config.mqtt.broker.protocol.option.WEBSOCKETS = WebSockets
 thing-type.config.mqtt.broker.publickey.label = Public Key Hash
 thing-type.config.mqtt.broker.publickey.description = If **publickeypin** is set this hash is used to verify the connection. Clear to allow a new public key pinning on the next connection attempt. If empty will be filled automatically by the next successful connection. An example input would be `SHA-256:83F9171E06A313118889F7D79302BD1B7A2042EE0CFD029ABF8DD06FFA6CD9D3`
 thing-type.config.mqtt.broker.publickeypin.label = Public Key Pinning

bundles/org.openhab.binding.mqtt/src/main/resources/OH-INF/thing/thing-types.xml

@@ -29,6 +29,35 @@
 				<default>false</default>
 			</parameter>
 
+			<parameter name="hostnameValidated" type="boolean">
+				<label>Hostname Validated</label>
+				<description>Validate hostname from certificate against server hostname for secure connection.</description>
+				<default>true</default>
+				<advanced>true</advanced>
+			</parameter>
+
+			<parameter name="protocol" type="text">
+				<label>Protocol</label>
+				<description>The protocol used for communicating with the broker.</description>
+				<options>
+					<option value="TCP">TCP</option>
+					<option value="WEBSOCKETS">WebSockets</option>
+				</options>
+				<default>TCP</default>
+				<advanced>true</advanced>
+			</parameter>
+
+			<parameter name="mqttVersion" type="text">
+				<label>MQTT Version</label>
+				<description>The MQTT version used for communicating with the broker.</description>
+				<options>
+					<option value="V3">Version 3</option>
+					<option value="V5">Version 5</option>
+				</options>
+				<default>V3</default>
+				<advanced>true</advanced>
+			</parameter>
+
 			<parameter name="qos" type="integer">
 				<label>Quality of Service</label>
 				<options>