src/catalogue/api/fields.py

   1 from rest_framework import serializers
   2 from sorl.thumbnail import default
   3 from catalogue.models import Book
   4
   5
   6 class BookLiked(serializers.ReadOnlyField):
   7     def __init__(self, source='pk', **kwargs):
   8         super(BookLiked, self).__init__(source=source, **kwargs)
   9
  10     def to_representation(self, value):
  11         request = self.context['request']
  12         if not hasattr(request, 'liked_books'):
  13             if request.user.is_authenticated():
  14                 request.liked_books = set(Book.tagged.with_any(request.user.tag_set.all()).values_list('id', flat=True))
  15             else:
  16                 request.liked_books = None
  17         if request.liked_books is not None:
  18             return value in request.liked_books
  19
  20
  21 class ThumbnailField(serializers.FileField):
  22     def __init__(self, geometry, *args, **kwargs):
  23         self.geometry = geometry
  24         super(ThumbnailField, self).__init__(*args, **kwargs)
  25
  26     def to_representation(self, value):
  27         if value:
  28             return super(ThumbnailField, self).to_representation(
  29                 default.backend.get_thumbnail(value, self.geometry)
  30             )