Tweaks to node update method

We override the update method so that the allowed_methods property can
be stripped before being sent to the server, avoiding validation issues.

We also introduce a new has_method method, which can be used in the UI
to check if the user can perform a specific method on the node.

pillarsdk/nodes.py

@@ -31,6 +31,30 @@ class Node(List, Find, Create, Post, Update, Delete, Replace):
             url = utils.join_url_params(url, params)
         return cls(api.get(url))
 
+    def update(self, attributes=None, api=None):
+        api = api or self.api
+        attributes = attributes or self.to_dict()
+        etag = attributes['_etag']
+        attributes.pop('_id')
+        attributes.pop('_etag')
+        attributes.pop('_created')
+        attributes.pop('_updated')
+        attributes.pop('_links')
+        attributes.pop('allowed_methods')
+        url = utils.join_url(self.path, str(self['_id']))
+        headers = utils.merge_dict(
+            self.http_headers(),
+            {'If-Match': str(etag)})
+        new_attributes = api.put(url, attributes, headers)
+        self.error = None
+        self.merge(new_attributes)
+        return self.success()
+
+    def has_method(self, method):
+        if method in self.allowed_methods:
+            return True
+        return False
+
 
 class NodeType(List, Find, Create, Post, Delete):
     """NodeType class wrapping the REST node_types endpoint