Add Config.from_mapping

flask/config.py

@@ -193,6 +193,28 @@ class Config(dict):
                 self[key] = obj[key]
         return True
 
+    def from_mapping(self, *mapping, **kwargs):
+        """Updates the config like :meth:`update` ignoring items with non-upper
+        keys.
+
+        .. versionadded:: 1.0
+        """
+        mappings = []
+        if len(mapping) == 1:
+            if hasattr(mapping[0], 'items'):
+                mappings.append(mapping[0].items())
+            else:
+                mappings.append(mapping[0])
+        elif len(mapping) > 1:
+            raise TypeError(
+                'expected at most 1 positional argument, got %d' % len(mapping)
+            )
+        mappings.append(kwargs.items())
+        for mapping in mappings:
+            for (key, value) in mapping:
+                if key.isupper():
+                    self[key] = value
+
     def get_namespace(self, namespace, lowercase=True):
         """Returns a dictionary containing a subset of configuration options
         that match the specified namespace/prefix. Example usage::