Merge pull request #114 from closeio/extensible-resource-serialize-fi…

…elds

Extensible resource field serialization

flask_mongorest/resources.py

@@ -332,6 +332,110 @@ def _subresource(self, obj):
  else:
  return None
 
+ def get_field_value(self, obj, field_name, field_instance=None, **kwargs):
+ """Return a json-serializable field value.
+
+ field_name is the name of the field in `obj` to be serialized.
+ field_instance is a MongoEngine field definition.
+ **kwargs are just any options to be passed through to child resources serializers.
+ """
+ has_field_instance = bool(field_instance)
+ field_instance = (field_instance or
+ self.document._fields.get(field_name, None) or
+ getattr(self.document, field_name, None))
+
+ # Determine the field value
+ if has_field_instance:
+ field_value = obj
+ elif isinstance(obj, dict):
+ return obj[field_name]
+ else:
+ try:
+ field_value = getattr(obj, field_name)
+ except AttributeError:
+ raise UnknownFieldError
+
+ return self.serialize_field_value(obj, field_name, field_instance, field_value, **kwargs)
+
+ def serialize_field_value(self, obj, field_name, field_instance, field_value, **kwargs):
+ """Select and delegate to an appropriate serializer method based on type of field instance.
+
+ field_value is an actual value to be serialized.
+ For other fields, see get_field_value method.
+ """
+ if isinstance(field_instance, (ReferenceField, GenericReferenceField, EmbeddedDocumentField)):
+ return self.serialize_document_field(field_name, field_value, **kwargs)
+
+ elif isinstance(field_instance, ListField):
+ return self.serialize_list_field(field_instance, field_name, field_value, **kwargs)
+
+ elif isinstance(field_instance, DictField):
+ return self.serialize_dict_field(field_instance, field_name, field_value, **kwargs)
+
+ elif callable(field_instance):
+ return self.serialize_callable_field(obj, field_instance, field_name, field_value, **kwargs)
+ return field_value
+
+ def serialize_callable_field(self, obj, field_instance, field_name, field_value, **kwargs):
+ """Execute a callable field and return it or serialize
+ it based on its related resource defined in the `related_resources` map.
+ """
+ if isinstance(field_value, list):
+ value = field_value
+ else:
+ if isbound(field_instance):
+ value = field_instance()
+ elif isbound(field_value):
+ value = field_value()
+ else:
+ value = field_instance(obj)
+ if field_name in self._related_resources:
+ if isinstance(value, list):
+ return [self._related_resources[field_name]().serialize_field(o, **kwargs) for o in value]
+ elif value is None:
+ return None
+ else:
+ return self._related_resources[field_name]().serialize_field(value, **kwargs)
+ return value
+
+ def serialize_dict_field(self, field_instance, field_name, field_value, **kwargs):
+ """Serialize each value based on an explicit field type
+ (e.g. if the schema defines a DictField(IntField), where all
+ the values in the dict should be ints).
+ """
+ if field_instance.field:
+ return {
+ key: self.get_field_value(elem, field_name, field_instance=field_instance.field, **kwargs)
+ for (key, elem) in field_value.items()
+ }
+ # ... or simply return the dict intact, if the field type
+ # wasn't specified
+ else:
+ return field_value
+
+ def serialize_list_field(self, field_instance, field_name, field_value, **kwargs):
+ """Serialize each item in the list separately."""
+ return [val for val in [self.get_field_value(elem, field_name, field_instance=field_instance.field, **kwargs) for elem in field_value] if val]
+
+ def serialize_document_field(self, field_name, field_value, **kwargs):
+ """If this field is a reference or an embedded document, either return
+ a DBRef or serialize it using a resource found in `related_resources`.
+ """
+ if field_name in self._related_resources:
+ return (
+ field_value and
+ not isinstance(field_value, DBRef) and
+ self._related_resources[field_name]().serialize_field(field_value, **kwargs)
+ )
+ else:
+ if DocumentProxy and isinstance(field_value, DocumentProxy):
+ # Don't perform a DBRef isinstance check below since
+ # it might trigger an extra query.
+ return field_value.to_dbref()
+ if isinstance(field_value, DBRef):
+ return field_value
+ return field_value and field_value.to_dbref()
+
  def serialize(self, obj, **kwargs):
  """
  Given an object, serialize it, turning it into its JSON
@@ -346,89 +450,6 @@ def serialize(self, obj, **kwargs):
  if subresource:
  return subresource.serialize(obj, **kwargs)
 
- def get(obj, field_name, field_instance=None):
- """
- @TODO needs significant cleanup
- """
-
- has_field_instance = bool(field_instance)
- field_instance = (field_instance or
- self.document._fields.get(field_name, None) or
- getattr(self.document, field_name, None))
-
- # Determine the field value
- if has_field_instance:
- field_value = obj
- elif isinstance(obj, dict):
- return obj[field_name]
- else:
- try:
- field_value = getattr(obj, field_name)
- except AttributeError:
- raise UnknownFieldError
-
- # If this field is a reference or an embedded document, either
- # return a DBRef or serialize it using a resource found in
- # `related_resources`.
- if isinstance(field_instance, (ReferenceField, GenericReferenceField, EmbeddedDocumentField)):
- if field_name in self._related_resources:
- return (
- field_value and
- not isinstance(field_value, DBRef) and
- self._related_resources[field_name]().serialize_field(field_value, **kwargs)
- )
- else:
- if DocumentProxy and isinstance(field_value, DocumentProxy):
- # Don't perform a DBRef isinstance check below since
- # it might trigger an extra query.
- return field_value.to_dbref()
- if isinstance(field_value, DBRef):
- return field_value
- return field_value and field_value.to_dbref()
-
- # If this field is a list, serialize each item in the list separately.
- elif isinstance(field_instance, ListField):
- return [val for val in [get(elem, field_name, field_instance=field_instance.field) for elem in field_value] if val]
-
- # If this field is a dict...
- elif isinstance(field_instance, DictField):
- # ... serialize each value based on an explicit field type
- # (e.g. if the schema defines a DictField(IntField), where all
- # the values in the dict should be ints).
- if field_instance.field:
- return {
- key: get(elem, field_name, field_instance=field_instance.field)
- for (key, elem) in field_value.items()
- }
- # ... or simply return the dict intact, if the field type
- # wasn't specified
- else:
- return field_value
-
- # If this field is callable, execute it and return it or serialize
- # it based on its related resource defined in the
- # `related_resources` map.
- elif callable(field_instance):
- if isinstance(field_value, list):
- value = field_value
- else:
- if isbound(field_instance):
- value = field_instance()
- elif isbound(field_value):
- value = field_value()
- else:
- value = field_instance(obj)
-
- if field_name in self._related_resources:
- if isinstance(value, list):
- return [self._related_resources[field_name]().serialize_field(o, **kwargs) for o in value]
- elif value is None:
- return None
- else:
- return self._related_resources[field_name]().serialize_field(value, **kwargs)
- return value
- return field_value
-
  # Get the requested fields
  requested_fields = self.get_requested_fields(**kwargs)
 
@@ -465,7 +486,7 @@ def get(obj, field_name, field_instance=None):
  data[renamed_field] = value
  else:
  try:
- data[renamed_field] = get(obj, field)
+ data[renamed_field] = self.get_field_value(obj, field, **kwargs)
  except UnknownFieldError:
  try:
  data[renamed_field] = self.value_for_field(obj, field)
@@ -897,6 +918,7 @@ def update_object(self, obj, data=None, save=True, parent_resources=None):
  def delete_object(self, obj, parent_resources=None):
  obj.delete()
 
+
 # Py2/3 compatible way to do metaclasses (or six.add_metaclass)
 body = vars(Resource).copy()
 body.pop('__dict__', None)

flask_mongorest/utils.py

@@ -28,6 +28,7 @@ def default(self, value, **kwargs):
  return str(value)
  return super(MongoEncoder, self).default(value, **kwargs)
 
+
 try:
  cmp
 except NameError: # Python 3

tests/__init__.py

@@ -1321,6 +1321,7 @@ def test_serialize_mongoengine_validation_error(self):
  }
  })
 
+
 if __name__ == '__main__':
  unittest.main()