Enable autodiscovery for mqtt cameras (#13697)

* Enable autodiscovery for mqtt cameras, BREAKING CHANGE: homogenisation topic->state_topic

* fix line too long

* fix topic->state_topic in test

* image shall not be the state of entity

homeassistant/components/camera/mqtt.py

@@ -19,7 +19,6 @@ from homeassistant.helpers import config_validation as cv
 _LOGGER = logging.getLogger(__name__)
 
 CONF_TOPIC = 'topic'
-
 DEFAULT_NAME = 'MQTT Camera'
 
 DEPENDENCIES = ['mqtt']
@@ -33,9 +32,13 @@ PLATFORM_SCHEMA = PLATFORM_SCHEMA.extend({
 @asyncio.coroutine
 def async_setup_platform(hass, config, async_add_devices, discovery_info=None):
     """Set up the MQTT Camera."""
-    topic = config[CONF_TOPIC]
+    if discovery_info is not None:
+        config = PLATFORM_SCHEMA(discovery_info)
 
-    async_add_devices([MqttCamera(config[CONF_NAME], topic)])
+    async_add_devices([MqttCamera(
+        config.get(CONF_NAME),
+        config.get(CONF_TOPIC)
+    )])
 
 
 class MqttCamera(Camera):

homeassistant/components/mqtt/discovery.py

@@ -20,10 +20,12 @@ TOPIC_MATCHER = re.compile(
     r'(?:(?P<node_id>[a-zA-Z0-9_-]+)/)?(?P<object_id>[a-zA-Z0-9_-]+)/config')
 
 SUPPORTED_COMPONENTS = [
-    'binary_sensor', 'cover', 'fan', 'light', 'sensor', 'switch', 'lock']
+    'binary_sensor', 'camera', 'cover', 'fan',
+    'light', 'sensor', 'switch', 'lock']
 
 ALLOWED_PLATFORMS = {
     'binary_sensor': ['mqtt'],
+    'camera': ['mqtt'],
     'cover': ['mqtt'],
     'fan': ['mqtt'],
     'light': ['mqtt', 'mqtt_json', 'mqtt_template'],