Files
consumocuidado-server/utils/tag_serializers.py
2021-01-26 10:58:57 +00:00

155 lines
5.4 KiB
Python

import traceback
from rest_framework import serializers
from rest_framework.fields import CharField, ListField
from rest_framework.serializers import raise_errors_on_nested_writes
from rest_framework.utils import model_meta
from tagulous.models.managers import TagRelatedManagerMixin
from taggit_serializer.serializers import TagListSerializerField, TaggitSerializer
class SingleTag(str):
def __init__(self, *args, **kwargs):
pass
def __str__(self):
return self
class SingleTagSerializerField(serializers.Field):
child = serializers.CharField()
default_error_messages = {
'not_a_str': 'Expected a string but got type "{input_type}".',
}
order_by = None
def __init__(self, **kwargs):
super(SingleTagSerializerField, self).__init__(**kwargs)
def to_internal_value(self, value):
if isinstance(value, str):
if not value:
value = ""
if not isinstance(value, str):
self.fail('not_a_str', input_type=type(value).__name__)
return value
def to_representation(self, value):
if not isinstance(value, SingleTag):
if not isinstance(value, str):
value = value.name
value = SingleTag(value)
return value
class CustomTagSerializer(serializers.Serializer):
"""
Differentiate between tags and single-tags
"""
def create(self, validated_data):
to_be_tagged, validated_data = self._pop_tags(validated_data)
# tag_object = super(CustomTagSerializer, self).create(validated_data)
raise_errors_on_nested_writes('create', self, validated_data)
ModelClass = self.Meta.model
# Remove many-to-many relationships from validated_data.
# They are not valid arguments to the default `.create()` method,
# as they require that the instance has already been saved.
info = model_meta.get_field_info(ModelClass)
many_to_many = {}
for field_name, relation_info in info.relations.items():
if relation_info.to_many and (field_name in validated_data):
many_to_many[field_name] = validated_data.pop(field_name)
try:
instance = ModelClass._default_manager.create(**validated_data)
except TypeError:
tb = traceback.format_exc()
msg = (
'Got a `TypeError` when calling `%s.%s.create()`. '
'This may be because you have a writable field on the '
'serializer class that is not a valid argument to '
'`%s.%s.create()`. You may need to make the field '
'read-only, or override the %s.create() method to handle '
'this correctly.\nOriginal exception was:\n %s' %
(
ModelClass.__name__,
ModelClass._default_manager.name,
ModelClass.__name__,
ModelClass._default_manager.name,
self.__class__.__name__,
tb
)
)
raise TypeError(msg)
# Save many-to-many relationships after the instance is created.
if many_to_many:
for field_name, value in many_to_many.items():
field = getattr(instance, field_name)
if field_name in ('tags', 'category', 'attributes'):
for item in value:
field.set(item)
else:
field.set(value)
return self._save_tags(instance, to_be_tagged)
def update(self, instance, validated_data):
to_be_tagged, validated_data = self._pop_tags(validated_data)
raise_errors_on_nested_writes('update', self, validated_data)
info = model_meta.get_field_info(instance)
# Simply set each attribute on the instance, and then save it.
# Note that unlike `.create()` we don't need to treat many-to-many
# relationships as being a special case. During updates we already
# have an instance pk for the relationships to be associated with.
m2m_fields = []
for attr, value in validated_data.items():
if attr in info.relations and info.relations[attr].to_many:
m2m_fields.append((attr, value))
else:
setattr(instance, attr, value)
instance.save()
# Note that many-to-many fields are set after updating instance.
# Setting m2m fields triggers signals which could potentially change
# updated instance and we do not want it to collide with .update()
for attr, value in m2m_fields:
field = getattr(instance, attr)
if attr in ('tags', 'category', 'attributes'):
for item in value:
field.set(item)
else:
field.set(value)
return self._save_tags(instance, to_be_tagged)
def _save_tags(self, tag_object, tags):
for key in tags.keys():
tag_values = tags.get(key)
getattr(tag_object, key).set(*tag_values)
return tag_object
def _pop_tags(self, validated_data):
to_be_tagged = {}
for key in self.fields.keys():
field = self.fields[key]
if isinstance(field, TagListSerializerField):
if key in validated_data:
to_be_tagged[key] = validated_data.pop(key)
return (to_be_tagged, validated_data)