src/catalogue/api/fields.py

   1 # -*- coding: utf-8 -*-
   2 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
   3 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
   4 #
   5 from rest_framework import serializers
   6 from catalogue.models import Book
   7
   8
   9 class BookLiked(serializers.ReadOnlyField):
  10     def __init__(self, source='pk', **kwargs):
  11         super(BookLiked, self).__init__(source=source, **kwargs)
  12
  13     def to_representation(self, value):
  14         request = self.context['request']
  15         if not hasattr(request, 'liked_books'):
  16             if request.user.is_authenticated():
  17                 request.liked_books = set(Book.tagged.with_any(request.user.tag_set.all()).values_list('id', flat=True))
  18             else:
  19                 request.liked_books = None
  20         if request.liked_books is not None:
  21             return value in request.liked_books