TMSS-272: added documentation

SAS/TMSS/src/tmss/tmssapp/serializers/widgets.py

@@ -14,20 +14,29 @@ class JSONEditorField(serializers.JSONField):
     """
     An enhanced JSONField that provides a nice editor widget with validation against the $schema in the json field value.
     """
-
     def __init__(self, schema_source: str=None, *args, **kwargs):
+        '''schema_source should be a string 'pointing to'  the used template and it's schema property.
+        For example in the SubtaskSerializer, we point to the specifications_template's schema like so:
+          specifications_doc = JSONEditorField(schema_source='specifications_template.schema')
+        '''
         self.schema_source = schema_source
         super().__init__(*args, **kwargs)
 
     def get_schema(self, json_data=None):
+        '''get the schema that this JSONEditorField is using via the schema_source'''
         try:
-            serializer = self.parent
-            return fields.get_attribute(serializer.instance, self.schema_source.split('.'))
+            if isinstance(self.parent.instance, list):
+                # the serializer is serializing a list of model instances, so we cannot get a single schema from a single instance
+                return None
+            return fields.get_attribute(self.parent.instance, self.schema_source.split('.'))
         except (AttributeError, TypeError):
             try:
                 if json_data and '$schema' in json_data:
                     schema_url = json_data['$schema']
-                    return json.loads(requests.get(schema_url).text)
+                    response = requests.get(schema_url)
+                    if response.status_code == 200:
+                        schema = response.text
+                        return json.loads(schema)
             except (KeyError, TypeError, json.JSONDecodeError):
                 pass
         return None
@@ -45,7 +54,7 @@ class JSONEditorField(serializers.JSONField):
 
     def to_representation(self, value):
         '''create representation of the json-schema-value,
-        with all common json schema refs pointing to the correct host,
+        with all common json schema $ref's pointing to the correct host,
         and inject the josdejong_jsoneditor_widget.html in the render style based on the requests accepted_media_type'''
         self.style = {}