+class BookProxy(models.Model):
+    class Meta:
+        managed = False
+
+    def __init__(self, book, key):
+        self.book = book
+        self.key = key
+
+    def __getattr__(self, item):
+        if item not in ('book', 'key'):
+            return self.book.__getattribute__(item)
+        else:
+            return self.__getattribute__(item)
+
+
+class QuerySetProxy(models.QuerySet):
+    def __init__(self, l):
+        self.list = l
+
+    def __iter__(self):
+        return iter(self.list)
+
+
+class FilterBooksHandler(AnonymousBooksHandler):
+    fields = book_tag_categories + [
+        'href', 'title', 'url', 'cover', 'cover_thumb', 'simple_thumb', 'slug', 'key']
+
+    def parse_bool(self, s):
+        if s in ('true', 'false'):
+            return s == 'true'
+        else:
+            return None
+
+    def read(self, request):
+        key_sep = '$'
+        search_string = request.GET.get('search')
+        is_lektura = self.parse_bool(request.GET.get('lektura'))
+        is_audiobook = self.parse_bool(request.GET.get('audiobook'))
+        preview = self.parse_bool(request.GET.get('preview'))
+
+        after = request.GET.get('after')
+        count = int(request.GET.get('count', 50))
+        books = Book.objects.distinct().order_by('slug')
+        if is_lektura is not None:
+            books = books.filter(has_audience=is_lektura)
+        if is_audiobook is not None:
+            if is_audiobook:
+                books = books.filter(media__type='mp3')
+            else:
+                books = books.exclude(media__type='mp3')
+        if preview is not None:
+            books = books.filter(preview=preview)
+        for key in request.GET:
+            if key in category_singular:
+                category = category_singular[key]
+                if category in book_tag_categories:
+                    slugs = request.GET[key].split(',')
+                    tags = Tag.objects.filter(category=category, slug__in=slugs)
+                    books = Book.tagged.with_any(tags, books)
+        if (search_string is not None) and len(search_string) < 3:
+            search_string = None
+        if search_string:
+            search_string = re_escape(search_string)
+            books_author = books.filter(cached_author__iregex='\m' + search_string)
+            books_title = books.filter(title__iregex='\m' + search_string)
+            books_title = books_title.exclude(id__in=list(books_author.values_list('id', flat=True)))
+            if after and (key_sep in after):
+                which, slug = after.split(key_sep, 1)
+                if which == 'title':
+                    book_lists = [(books_title.filter(slug__gt=slug), 'title')]
+                else:  # which == 'author'
+                    book_lists = [(books_author.filter(slug__gt=slug), 'author'), (books_title, 'title')]
+            else:
+                book_lists = [(books_author, 'author'), (books_title, 'title')]
+        else:
+            if after and key_sep in after:
+                which, slug = after.split(key_sep, 1)
+                books = books.filter(slug__gt=slug)
+            book_lists = [(books, 'book')]
+
+        filtered_books = []
+        for book_list, label in book_lists:
+            book_list = book_list.only('slug', 'title', 'cover', 'cover_thumb')
+            for category in book_tag_categories:
+                book_list = prefetch_relations(book_list, category)
+            remaining_count = count - len(filtered_books)
+            new_books = [BookProxy(book, '%s%s%s' % (label, key_sep, book.slug))
+                         for book in book_list[:remaining_count]]
+            filtered_books += new_books
+            if len(filtered_books) == count:
+                break
+
+        return QuerySetProxy(filtered_books)
+
+