diff options
Diffstat (limited to 'rest_framework')
| -rw-r--r-- | rest_framework/serializers.py | 81 |
1 files changed, 60 insertions, 21 deletions
diff --git a/rest_framework/serializers.py b/rest_framework/serializers.py index e1851ddd..68d0b8cc 100644 --- a/rest_framework/serializers.py +++ b/rest_framework/serializers.py @@ -561,6 +561,64 @@ class ListSerializer(BaseSerializer): # ModelSerializer & HyperlinkedModelSerializer # -------------------------------------------- +def raise_errors_on_nested_writes(method_name, serializer): + """ + Give explicit errors when users attempt to pass writable nested data. + + If we don't do this explicitly they'd get a less helpful error when + calling `.save()` on the serializer. + + We don't *automatically* support these sorts of nested writes brecause + there are too many ambiguities to define a default behavior. + + Eg. Suppose we have a `UserSerializer` with a nested profile. How should + we handle the case of an update, where the `profile` realtionship does + not exist? Any of the following might be valid: + + * Raise an application error. + * Silently ignore the nested part of the update. + * Automatically create a profile instance. + """ + + # Ensure we don't have a writable nested field. For example: + # + # class UserSerializer(ModelSerializer): + # ... + # profile = ProfileSerializer() + assert not any( + isinstance(field, BaseSerializer) and (key in validated_attrs) + for key, field in serializer.fields.items() + ), ( + 'The `.{method_name}()` method does not support nested writable ' + 'fields by default. Write an explicit `.{method_name}()` method for ' + 'serializer `{module}.{class_name}`, or set `read_only=True` on ' + 'nested serializer fields.'.format( + method_name=method_name, + module=serializer.__class__.__module__, + class_name=serializer.__class__.__name__ + ) + ) + + # Ensure we don't have a writable dotted-source field. For example: + # + # class UserSerializer(ModelSerializer): + # ... + # address = serializer.CharField('profile.address') + assert not any( + '.' in field.source and (key in validated_attrs) + for key, field in serializer.fields.items() + ), ( + 'The `.{method_name}()` method does not support writable dotted-source ' + 'fields by default. Write an explicit `.{method_name}()` method for ' + 'serializer `{module}.{class_name}`, or set `read_only=True` on ' + 'dotted-source serializer fields.'.format( + method_name=method_name, + module=serializer.__class__.__module__, + class_name=serializer.__class__.__name__ + ) + ) + + class ModelSerializer(Serializer): """ A `ModelSerializer` is just a regular `Serializer`, except that: @@ -624,18 +682,7 @@ class ModelSerializer(Serializer): If you want to support writable nested relationships you'll need to write an explicit `.create()` method. """ - # Check that the user isn't trying to handle a writable nested field. - # If we don't do this explicitly they'd likely get a confusing - # error at the point of calling `Model.objects.create()`. - assert not any( - isinstance(field, BaseSerializer) and (key in validated_attrs) - for key, field in self.fields.items() - ), ( - 'The `.create()` method does not support nested writable fields ' - 'by default. Write an explicit `.create()` method for serializer ' - '`%s.%s`, or set `read_only=True` on nested serializer fields.' % - (self.__class__.__module__, self.__class__.__name__) - ) + raise_errors_on_nested_writes('create', self) ModelClass = self.Meta.model @@ -675,15 +722,7 @@ class ModelSerializer(Serializer): return instance def update(self, instance, validated_data): - assert not any( - isinstance(field, BaseSerializer) and (key in validated_attrs) - for key, field in self.fields.items() - ), ( - 'The `.update()` method does not support nested writable fields ' - 'by default. Write an explicit `.update()` method for serializer ' - '`%s.%s`, or set `read_only=True` on nested serializer fields.' % - (self.__class__.__module__, self.__class__.__name__) - ) + raise_errors_on_nested_writes('update', self) for attr, value in validated_data.items(): setattr(instance, attr, value) |