Add websocket list APIs for the registries (#16597)

* Add websocket list APIs for the registries

* Remove identifiers

* Fix tests

* Use ordered dict

homeassistant/components/config/device_registry.py

@@ -0,0 +1,46 @@
+"""HTTP views to interact with the device registry."""
+import voluptuous as vol
+
+from homeassistant.core import callback
+from homeassistant.helpers.device_registry import async_get_registry
+from homeassistant.components import websocket_api
+
+DEPENDENCIES = ['websocket_api']
+
+WS_TYPE_LIST = 'config/device_registry/list'
+SCHEMA_WS_LIST = websocket_api.BASE_COMMAND_MESSAGE_SCHEMA.extend({
+    vol.Required('type'): WS_TYPE_LIST,
+})
+
+
+async def async_setup(hass):
+    """Enable the Entity Registry views."""
+    hass.components.websocket_api.async_register_command(
+        WS_TYPE_LIST, websocket_list_devices,
+        SCHEMA_WS_LIST
+    )
+    return True
+
+
+@callback
+def websocket_list_devices(hass, connection, msg):
+    """Handle list devices command.
+
+    Async friendly.
+    """
+    async def retrieve_entities():
+        """Get devices from registry."""
+        registry = await async_get_registry(hass)
+        connection.send_message_outside(websocket_api.result_message(
+            msg['id'], [{
+                'config_entries': list(entry.config_entries),
+                'connections': list(entry.connections),
+                'manufacturer': entry.manufacturer,
+                'model': entry.model,
+                'name': entry.name,
+                'sw_version': entry.sw_version,
+                'id': entry.id,
+            } for entry in registry.devices.values()]
+        ))
+
+    hass.async_add_job(retrieve_entities())