Added client support for self signed certificate on MQTT server

docs/references/mqttclient.rst

@@ -164,6 +164,7 @@ The :class:`~hbmqtt.client.MQTTClient` ``__init__`` method accepts a ``config``
 * ``default_qos``: Default QoS (``0``) used by :meth:`~hbmqtt.client.MQTTClient.publish` if ``qos`` argument is not given.
 * ``default_retain``: Default retain (``False``) used by :meth:`~hbmqtt.client.MQTTClient.publish` if ``qos`` argument is not given.,
 * ``auto_reconnect``: enable or disable auto-reconnect feature (defaults to ``True``).
+* ``ca_certs``: a string path to the Certificate Authority certificate files that are to be treated as trusted by this client. If provided, the client will require the broker to have a certificate signed by the Certificate Authorities in ca_certs and will communicate using TLS, if not provided the client will use the system's Certificate Authorities.
 * ``reconnect_max_interval``: maximum interval (in seconds) to wait before two connection retries (defaults to ``10``).
 * ``reconnect_retries``: maximum number of connect retries (defaults to ``2``). Negative value will cause client to reconnect infinietly.
 Default QoS and default retain can also be overriden by adding a ``topics`` with may contain QoS and retain values for specific topics. See the following example:

hbmqtt/client.py

@@ -396,6 +396,8 @@ def _connect_coro(self):
                 sc.load_cert_chain(self.config['certfile'], self.config['keyfile'])
             if 'check_hostname' in self.config and isinstance(self.config['check_hostname'], bool):
                 sc.check_hostname = self.config['check_hostname']
+            if 'ca_certs' in self.config:
+                sc.load_verify_locations(self.config['ca_certs'])
             kwargs['ssl'] = sc
 
         try: