Extract data validator to own file and add tests (#12401)

homeassistant/components/http/data_validator.py

@@ -0,0 +1,51 @@
+"""Decorator for view methods to help with data validation."""
+import asyncio
+from functools import wraps
+import logging
+
+import voluptuous as vol
+
+_LOGGER = logging.getLogger(__name__)
+
+
+class RequestDataValidator:
+    """Decorator that will validate the incoming data.
+
+    Takes in a voluptuous schema and adds 'post_data' as
+    keyword argument to the function call.
+
+    Will return a 400 if no JSON provided or doesn't match schema.
+    """
+
+    def __init__(self, schema, allow_empty=False):
+        """Initialize the decorator."""
+        self._schema = schema
+        self._allow_empty = allow_empty
+
+    def __call__(self, method):
+        """Decorate a function."""
+        @asyncio.coroutine
+        @wraps(method)
+        def wrapper(view, request, *args, **kwargs):
+            """Wrap a request handler with data validation."""
+            data = None
+            try:
+                data = yield from request.json()
+            except ValueError:
+                if not self._allow_empty or \
+                   (yield from request.content.read()) != b'':
+                    _LOGGER.error('Invalid JSON received.')
+                    return view.json_message('Invalid JSON.', 400)
+                data = {}
+
+            try:
+                kwargs['data'] = self._schema(data)
+            except vol.Invalid as err:
+                _LOGGER.error('Data does not match schema: %s', err)
+                return view.json_message(
+                    'Message format incorrect: {}'.format(err), 400)
+
+            result = yield from method(view, request, *args, **kwargs)
+            return result
+
+        return wrapper