Using cache middleware instead of various caching micro-strategies,

[wolnelektury.git] / apps / api / handlers.py

diff --git a/apps/api/handlers.py b/apps/api/handlers.py
index 32a3ce3..5fe931e 100644 (file)
--- a/apps/api/handlers.py
+++ b/apps/api/handlers.py
@@ -1,23 +1,27 @@
 # -*- coding: utf-8 -*-
 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.
 # -*- coding: utf-8 -*-
 # This file is part of Wolnelektury, licensed under GNU Affero GPLv3 or later.
 # Copyright © Fundacja Nowoczesna Polska. See NOTICE for more information.

+#
+import json

 
 

-from datetime import datetime, timedelta
-
-from django.conf import settings

 from django.contrib.sites.models import Site
 from django.core.urlresolvers import reverse
 from django.contrib.sites.models import Site
 from django.core.urlresolvers import reverse

-from django.http import Http404
-from django.shortcuts import get_object_or_404
-from piston.handler import BaseHandler
+from django.utils.functional import lazy
+from piston.handler import AnonymousBaseHandler, BaseHandler

 from piston.utils import rc
 from piston.utils import rc

+from sorl.thumbnail import default
+
+from catalogue.forms import BookImportForm
+from catalogue.models import Book, Tag, BookMedia, Fragment, Collection
+from picture.models import Picture
+from picture.forms import PictureImportForm

 
 

-from api.helpers import timestamp
-from api.models import Deleted
-from catalogue.models import Book, Tag, BookMedia, Fragment
+from stats.utils import piwik_track

 
 

+from . import emitters # Register our emitters

 
 

-API_BASE = WL_BASE = MEDIA_BASE = 'http://' + Site.objects.get_current().domain
+API_BASE = WL_BASE = MEDIA_BASE = lazy(
+    lambda: u'http://' + Site.objects.get_current().domain, unicode)()

 
 
 category_singular = {
 
 
 category_singular = {


@@ -28,23 +32,27 @@ category_singular = {
     'themes': 'theme',
     'books': 'book',
 }
     'themes': 'theme',
     'books': 'book',
 }

-category_plural={}
+category_plural = {}

 for k, v in category_singular.items():
     category_plural[v] = k
 
 for k, v in category_singular.items():
     category_plural[v] = k
 

+book_tag_categories = ['author', 'epoch', 'kind', 'genre']
+
+

 
 def read_tags(tags, allowed):
     """ Reads a path of filtering tags.
 
     :param str tags: a path of category and slug pairs, like: authors/an-author/...
     :returns: list of Tag objects
 
 def read_tags(tags, allowed):
     """ Reads a path of filtering tags.
 
     :param str tags: a path of category and slug pairs, like: authors/an-author/...
     :returns: list of Tag objects

-    :raises: django.http.Http404
+    :raises: ValueError when tags can't be found

     """
     if not tags:
     """
     if not tags:

-        return []
+        return [], []

 
     tags = tags.strip('/').split('/')
     real_tags = []
 
     tags = tags.strip('/').split('/')
     real_tags = []

+    books = []

     while tags:
         category = tags.pop(0)
         slug = tags.pop(0)
     while tags:
         category = tags.pop(0)
         slug = tags.pop(0)


@@ -52,17 +60,22 @@ def read_tags(tags, allowed):
         try:
             category = category_singular[category]
         except KeyError:
         try:
             category = category_singular[category]
         except KeyError:

-            raise Http404
+            raise ValueError('Unknown category.')

 
         if not category in allowed:
 
         if not category in allowed:

-            raise Http404
+            raise ValueError('Category not allowed.')

 
 

-        # !^%@#$^#!

         if category == 'book':
         if category == 'book':

-            slug = 'l-' + slug
+            try:
+                books.append(Book.objects.get(slug=slug))
+            except Book.DoesNotExist:
+                raise ValueError('Unknown book.')

 
 

-        real_tags.append(get_object_or_404(Tag, category=category, slug=slug))
-    return real_tags
+        try:
+            real_tags.append(Tag.objects.get(category=category, slug=slug))
+        except Tag.DoesNotExist:
+            raise ValueError('Tag not found')
+    return real_tags, books

 
 
 # RESTful handlers
 
 
 # RESTful handlers


@@ -72,7 +85,7 @@ class BookMediaHandler(BaseHandler):
     """ Responsible for representing media in Books. """
 
     model = BookMedia
     """ Responsible for representing media in Books. """
 
     model = BookMedia

-    fields = ['name', 'type', 'url']
+    fields = ['name', 'type', 'url', 'artist', 'director']

 
     @classmethod
     def url(cls, media):
 
     @classmethod
     def url(cls, media):


@@ -80,50 +93,87 @@ class BookMediaHandler(BaseHandler):
 
         return MEDIA_BASE + media.file.url
 
 
         return MEDIA_BASE + media.file.url
 

+    @classmethod
+    def artist(cls, media):
+        return media.extra_info.get('artist_name', '')

 
 

-class BookDetailHandler(BaseHandler):
-    """ Main handler for Book objects.
+    @classmethod
+    def director(cls, media):
+        return media.extra_info.get('director_name', '')

 
 

-    Responsible for lists of Book objects
-    and fields used for representing Books.

 
 

-    """
-    allowed_methods = ['GET']
-    fields = ['title', 'parent',
-        'xml', 'html', 'pdf', 'epub', 'txt',
-        'media', 'url'] + category_singular.keys()
+class BookDetails(object):
+    """Custom fields used for representing Books."""

 
 

-    def read(self, request, slug):
-        """ Returns details of a book, identified by a slug. """
+    @classmethod
+    def href(cls, book):
+        """ Returns an URI for a Book in the API. """
+        return API_BASE + reverse("api_book", args=[book.slug])
+
+    @classmethod
+    def url(cls, book):
+        """ Returns Book's URL on the site. """
+
+        return WL_BASE + book.get_absolute_url()

 
 

-        return get_object_or_404(Book, slug=slug)
+    @classmethod
+    def children(cls, book):
+        """ Returns all children for a book. """
+
+        return book.children.all()

 
 

+    @classmethod
+    def media(cls, book):
+        """ Returns all media for a book. """
+        return book.media.all()

 
 

-class BooksHandler(BaseHandler):
+    @classmethod
+    def cover(cls, book):
+        return MEDIA_BASE + book.cover.url if book.cover else ''
+
+    @classmethod
+    def cover_thumb(cls, book):
+        return MEDIA_BASE + default.backend.get_thumbnail(
+                    book.cover, "139x193").url if book.cover else ''
+
+
+
+class BookDetailHandler(BaseHandler, BookDetails):

     """ Main handler for Book objects.
 
     """ Main handler for Book objects.
 

-    Responsible for lists of Book objects
-    and fields used for representing Books.
+    Responsible for single Book details.
+    """
+    allowed_methods = ['GET']
+    fields = ['title', 'parent', 'children'] + Book.formats + [
+        'media', 'url', 'cover', 'cover_thumb'] + [
+            category_plural[c] for c in book_tag_categories]
+
+    @piwik_track
+    def read(self, request, book):
+        """ Returns details of a book, identified by a slug and lang. """
+        try:
+            return Book.objects.get(slug=book)
+        except Book.DoesNotExist:
+            return rc.NOT_FOUND
+

 
 

+class AnonymousBooksHandler(AnonymousBaseHandler, BookDetails):
+    """ Main handler for Book objects.
+
+    Responsible for lists of Book objects.

     """
     allowed_methods = ('GET',)
     model = Book
     """
     allowed_methods = ('GET',)
     model = Book

-    fields = ['href', 'title']
-
-    categories = set(['author', 'epoch', 'kind', 'genre'])
+    fields = book_tag_categories + ['href', 'title', 'url', 'cover', 'cover_thumb']

 
     @classmethod
 
     @classmethod

-    def href(cls, book):
-        """ Returns an URI for a Book in the API. """
-        return API_BASE + reverse("api_book", args=[book.slug])
+    def genres(cls, book):
+        """ Returns all media for a book. """
+        return book.tags.filter(category='genre')

 
 

-    @classmethod
-    def url(cls, book):
-        """ Returns Book's URL on the site. """
-
-        return WL_BASE + book.get_absolute_url()
-
-    def read(self, request, tags, top_level=False):
+    @piwik_track
+    def read(self, request, tags=None, top_level=False,
+                audiobooks=False, daisy=False, pk=None):

         """ Lists all books with given tags.
 
         :param tags: filtering tags; should be a path of categories
         """ Lists all books with given tags.
 
         :param tags: filtering tags; should be a path of categories


@@ -132,14 +182,63 @@ class BooksHandler(BaseHandler):
              it's children are aren't. By default all books matching the tags
              are returned.
         """
              it's children are aren't. By default all books matching the tags
              are returned.
         """

-        tags = read_tags(tags, allowed=self.categories)
+        if pk is not None:
+            try:
+                return Book.objects.get(pk=pk)
+            except Book.DoesNotExist:
+                return rc.NOT_FOUND
+
+        try:
+            tags, _ancestors = read_tags(tags, allowed=book_tag_categories)
+        except ValueError:
+            return rc.NOT_FOUND
+

         if tags:
             if top_level:
         if tags:
             if top_level:

-                return Book.tagged_top_level(tags)
+                books = Book.tagged_top_level(tags)
+                return books if books else rc.NOT_FOUND

             else:
             else:

-                return Book.tagged.with_all(tags)
+                books = Book.tagged.with_all(tags)
+        else:
+            books = Book.objects.all()
+
+        if top_level:
+            books = books.filter(parent=None)
+        if audiobooks:
+            books = books.filter(media__type='mp3').distinct()
+        if daisy:
+            books = books.filter(media__type='daisy').distinct()
+
+        if books.exists():
+            return books

         else:
         else:

-            return Book.objects.all()
+            return rc.NOT_FOUND
+
+    def create(self, request, *args, **kwargs):
+        return rc.FORBIDDEN
+
+
+class BooksHandler(BookDetailHandler):
+    allowed_methods = ('GET', 'POST')
+    model = Book
+    fields = book_tag_categories + ['href', 'title', 'url', 'cover', 'cover_thumb']
+    anonymous = AnonymousBooksHandler
+
+    def create(self, request, *args, **kwargs):
+        if not request.user.has_perm('catalogue.add_book'):
+            return rc.FORBIDDEN
+
+        data = json.loads(request.POST.get('data'))
+        form = BookImportForm(data)
+        if form.is_valid():
+            form.save()
+            return rc.CREATED
+        else:
+            return rc.NOT_FOUND
+
+
+class EBooksHandler(AnonymousBooksHandler):
+    fields = ('author', 'href', 'title', 'cover') + tuple(Book.ebook_formats)

 
 
 # add categorized tags fields for Book
 
 
 # add categorized tags fields for Book


@@ -148,8 +247,14 @@ def _tags_getter(category):
     def get_tags(cls, book):
         return book.tags.filter(category=category)
     return get_tags
     def get_tags(cls, book):
         return book.tags.filter(category=category)
     return get_tags

+def _tag_getter(category):
+    @classmethod
+    def get_tag(cls, book):
+        return ', '.join(tag.name for tag in book.tags.filter(category=category))
+    return get_tag

 for plural, singular in category_singular.items():
 for plural, singular in category_singular.items():

-    setattr(BooksHandler, plural, _tags_getter(singular))
+    setattr(BookDetails, plural, _tags_getter(singular))
+    setattr(BookDetails, singular, _tag_getter(singular))

 
 # add fields for files in Book
 def _file_getter(format):
 
 # add fields for files in Book
 def _file_getter(format):


@@ -162,46 +267,57 @@ def _file_getter(format):
         else:
             return ''
     return get_file
         else:
             return ''
     return get_file

-for format in ('xml', 'txt', 'html', 'epub', 'pdf'):
-    setattr(BooksHandler, format, _file_getter(format))
+for format in Book.formats:
+    setattr(BookDetails, format, _file_getter(format))

 
 
 
 

-class TagDetailHandler(BaseHandler):
-    """ Responsible for details of a single Tag object. """
+class CollectionDetails(object):
+    """Custom Collection fields."""

 
 

-    fields = ['name', 'sort_key', 'description']
+    @classmethod
+    def href(cls, collection):
+        """ Returns URI in the API for the collection. """

 
 

-    def read(self, request, category, slug):
-        """ Returns details of a tag, identified by category and slug. """
+        return API_BASE + reverse("api_collection", args=[collection.slug])

 
 

-        try:
-            category_sng = category_singular[category]
-        except KeyError, e:
-            return rc.NOT_FOUND
+    @classmethod
+    def url(cls, collection):
+        """ Returns URL on the site. """

 
 

-        return get_object_or_404(Tag, category=category_sng, slug=slug)
+        return WL_BASE + collection.get_absolute_url()

 
 

+    @classmethod
+    def books(cls, collection):
+        return Book.objects.filter(collection.get_query())

 
 

-class TagsHandler(BaseHandler):
-    """ Main handler for Tag objects.

 
 

-    Responsible for lists of Tag objects
-    and fields used for representing Tags.

 
 

-    """
+class CollectionDetailHandler(BaseHandler, CollectionDetails):

     allowed_methods = ('GET',)
     allowed_methods = ('GET',)

-    model = Tag
-    fields = ['name', 'href']
-
-    def read(self, request, category):
-        """ Lists all tags in the category (eg. all themes). """
+    fields = ['url', 'title', 'description', 'books']

 
 

+    @piwik_track
+    def read(self, request, slug):
+        """ Returns details of a collection, identified by slug. """

         try:
         try:

-            category_sng = category_singular[category]
-        except KeyError, e:
+            return Collection.objects.get(slug=slug)
+        except Collection.DoesNotExist:

             return rc.NOT_FOUND
 
             return rc.NOT_FOUND
 

-        return Tag.objects.filter(category=category_sng)
+
+class CollectionsHandler(BaseHandler, CollectionDetails):
+    allowed_methods = ('GET',)
+    model = Collection
+    fields = ['url', 'href', 'title']
+
+    @piwik_track
+    def read(self, request):
+        """ Returns all collections. """
+        return Collection.objects.all()
+
+
+class TagDetails(object):
+    """Custom Tag fields."""

 
     @classmethod
     def href(cls, tag):
 
     @classmethod
     def href(cls, tag):


@@ -209,44 +325,74 @@ class TagsHandler(BaseHandler):
 
         return API_BASE + reverse("api_tag", args=[category_plural[tag.category], tag.slug])
 
 
         return API_BASE + reverse("api_tag", args=[category_plural[tag.category], tag.slug])
 

+    @classmethod
+    def url(cls, tag):
+        """ Returns URL on the site. """

 
 

-class FragmentDetailHandler(BaseHandler):
-    fields = ['book', 'anchor', 'text', 'url', 'themes']
+        return WL_BASE + tag.get_absolute_url()

 
 

-    def read(self, request, slug, anchor):
-        """ Returns details of a fragment, identified by book slug and anchor. """

 
 

-        return get_object_or_404(Fragment, book__slug=slug, anchor=anchor)
+class TagDetailHandler(BaseHandler, TagDetails):
+    """ Responsible for details of a single Tag object. """

 
 

+    fields = ['name', 'url', 'sort_key', 'description']

 
 

-class FragmentsHandler(BaseHandler):
-    """ Main handler for Fragments.
+    @piwik_track
+    def read(self, request, category, slug):
+        """ Returns details of a tag, identified by category and slug. """

 
 

-    Responsible for lists of Fragment objects
-    and fields used for representing Fragments.
+        try:
+            category_sng = category_singular[category]
+        except KeyError, e:
+            return rc.NOT_FOUND
+
+        try:
+            return Tag.objects.get(category=category_sng, slug=slug)
+        except Tag.DoesNotExist:
+            return rc.NOT_FOUND
+
+
+class TagsHandler(BaseHandler, TagDetails):
+    """ Main handler for Tag objects.
+
+    Responsible for lists of Tag objects
+    and fields used for representing Tags.

 
     """
 
     """

-    model = Fragment
-    fields = ['book', 'anchor', 'href']

     allowed_methods = ('GET',)
     allowed_methods = ('GET',)

+    model = Tag
+    fields = ['name', 'href', 'url']

 
 

-    categories = set(['author', 'epoch', 'kind', 'genre', 'book', 'theme'])
+    @piwik_track
+    def read(self, request, category=None, pk=None):
+        """ Lists all tags in the category (eg. all themes). """
+        if pk is not None:
+            try:
+                return Tag.objects.exclude(category='set').get(pk=pk)
+            except Book.DoesNotExist:
+                return rc.NOT_FOUND

 
 

-    def read(self, request, tags):
-        """ Lists all fragments with given book, tags, themes.
+        try:
+            category_sng = category_singular[category]
+        except KeyError, e:
+            return rc.NOT_FOUND

 
 

-        :param tags: should be a path of categories and slugs, i.e.:
-             books/book-slug/authors/an-author/themes/a-theme/
+        tags = Tag.objects.filter(category=category_sng).exclude(items=None)
+        if tags.exists():
+            return tags
+        else:
+            return rc.NOT_FOUND

 
 

-        """
-        tags = read_tags(tags, allowed=self.categories)
-        return Fragment.tagged.with_all(tags).select_related('book')
+
+class FragmentDetails(object):
+    """Custom Fragment fields."""

 
     @classmethod
     def href(cls, fragment):
         """ Returns URI in the API for the fragment. """
 
 
     @classmethod
     def href(cls, fragment):
         """ Returns URI in the API for the fragment. """
 

-        return API_BASE + reverse("api_fragment", args=[fragment.book.slug, fragment.anchor])
+        return API_BASE + reverse("api_fragment",
+            args=[fragment.book.slug, fragment.anchor])

 
     @classmethod
     def url(cls, fragment):
 
     @classmethod
     def url(cls, fragment):


@@ -261,251 +407,63 @@ class FragmentsHandler(BaseHandler):
         return fragment.tags.filter(category='theme')
 
 
         return fragment.tags.filter(category='theme')
 
 

+class FragmentDetailHandler(BaseHandler, FragmentDetails):
+    fields = ['book', 'anchor', 'text', 'url', 'themes']

 
 

+    @piwik_track
+    def read(self, request, book, anchor):
+        """ Returns details of a fragment, identified by book slug and anchor. """
+        try:
+            return Fragment.objects.get(book__slug=book, anchor=anchor)
+        except Fragment.DoesNotExist:
+            return rc.NOT_FOUND

 
 

-# Changes handlers
-
-class CatalogueHandler(BaseHandler):
-
-    @staticmethod
-    def fields(request, name):
-        fields_str = request.GET.get(name) if request is not None else None
-        return fields_str.split(',') if fields_str is not None else None
-
-    @staticmethod
-    def until(t=None):
-        """ Returns time suitable for use as upper time boundary for check.
-
-            Used to avoid issues with time between setting the change stamp
-            and actually saving the model in database.
-            Cuts the microsecond part to avoid issues with DBs where time has
-            more precision.
-
-            :param datetime t: manually sets the upper boundary
-
-        """
-        # set to five minutes ago, to avoid concurrency issues
-        if t is None:
-            t = datetime.now() - timedelta(seconds=settings.API_WAIT)
-        # set to whole second in case DB supports something smaller
-        return t.replace(microsecond=0)
-
-    @staticmethod
-    def book_dict(book, fields=None):
-        all_fields = ('url', 'title', 'description',
-                      'gazeta_link', 'wiki_link',
-                      'xml', 'epub', 'txt', 'pdf', 'html',
-                      'mp3', 'ogg', 'daisy',
-                      'parent', 'parent_number',
-                      'tags',
-                      'license', 'license_description', 'source_name',
-                      'technical_editors', 'editors',
-                      'author', 'sort_key',
-                     )
-        if fields:
-            fields = (f for f in fields if f in all_fields)
-        else:
-            fields = all_fields
-
-        extra_info = book.get_extra_info_value()
-
-        obj = {}
-        for field in fields:
-
-            if field in ('xml', 'epub', 'txt', 'pdf', 'html'):
-                f = getattr(book, field+'_file')
-                if f:
-                    obj[field] = {
-                        'url': f.url,
-                        'size': f.size,
-                    }
-
-            elif field in ('mp3', 'ogg', 'daisy'):
-                media = []
-                for m in book.media.filter(type=field):
-                    media.append({
-                        'url': m.file.url,
-                        'size': m.file.size,
-                    })
-                if media:
-                    obj[field] = media
-
-            elif field == 'url':
-                obj[field] = book.get_absolute_url()

 
 

-            elif field == 'tags':
-                obj[field] = [t.id for t in book.tags.exclude(category__in=('book', 'set'))]
+class FragmentsHandler(BaseHandler, FragmentDetails):
+    """ Main handler for Fragments.

 
 

-            elif field == 'author':
-                obj[field] = ", ".join(t.name for t in book.tags.filter(category='author'))
+    Responsible for lists of Fragment objects
+    and fields used for representing Fragments.

 
 

-            elif field == 'parent':
-                obj[field] = book.parent_id
+    """
+    model = Fragment
+    fields = ['book', 'url', 'anchor', 'href']
+    allowed_methods = ('GET',)

 
 

-            elif field in ('license', 'license_description', 'source_name',
-                      'technical_editors', 'editors'):
-                f = extra_info.get(field)
-                if f:
-                    obj[field] = f
+    categories = set(['author', 'epoch', 'kind', 'genre', 'book', 'theme'])

 
 

-            else:
-                f = getattr(book, field)
-                if f:
-                    obj[field] = f
+    @piwik_track
+    def read(self, request, tags):
+        """ Lists all fragments with given book, tags, themes.

 
 

-        obj['id'] = book.id
-        return obj
+        :param tags: should be a path of categories and slugs, i.e.:
+             books/book-slug/authors/an-author/themes/a-theme/

 
 

-    @classmethod
-    def book_changes(cls, request=None, since=0, until=None, fields=None):
-        since = datetime.fromtimestamp(int(since))
-        until = cls.until(until)
-
-        changes = {
-            'time_checked': timestamp(until)
-        }
-
-        if not fields:
-            fields = cls.fields(request, 'book_fields')
-
-        added = []
-        updated = []
-        deleted = []
-
-        last_change = since
-        for book in Book.objects.filter(changed_at__gte=since,
-                    changed_at__lt=until):
-            book_d = cls.book_dict(book, fields)
-            updated.append(book_d)
-        if updated:
-            changes['updated'] = updated
-
-        for book in Deleted.objects.filter(content_type=Book, 
-                    deleted_at__gte=since,
-                    deleted_at__lt=until,
-                    created_at__lt=since):
-            deleted.append(book.id)
-        if deleted:
-            changes['deleted'] = deleted
-
-        return changes
-
-    @staticmethod
-    def tag_dict(tag, fields=None):
-        all_fields = ('name', 'category', 'sort_key', 'description',
-                      'gazeta_link', 'wiki_link',
-                      'url', 'books',
-                     )
-
-        if fields:
-            fields = (f for f in fields if f in all_fields)
+        """
+        try:
+            tags, ancestors = read_tags(tags, allowed=self.categories)
+        except ValueError:
+            return rc.NOT_FOUND
+        fragments = Fragment.tagged.with_all(tags).select_related('book')
+        if fragments.exists():
+            return fragments

         else:
         else:

-            fields = all_fields
-
-        obj = {}
-        for field in fields:
-
-            if field == 'url':
-                obj[field] = tag.get_absolute_url()
-
-            elif field == 'books':
-                obj[field] = [b.id for b in Book.tagged_top_level([tag])]
+            return rc.NOT_FOUND

 
 

-            elif field == 'sort_key':
-                obj[field] = tag.sort_key

 
 

-            else:
-                f = getattr(tag, field)
-                if f:
-                    obj[field] = f
+class PictureHandler(BaseHandler):
+    model = Picture
+    fields = ('slug', 'title')
+    allowed_methods = ('POST',)

 
 

-        obj['id'] = tag.id
-        return obj
+    def create(self, request):
+        if not request.user.has_perm('picture.add_picture'):
+            return rc.FORBIDDEN

 
 

-    @classmethod
-    def tag_changes(cls, request=None, since=0, until=None, fields=None, categories=None):
-        since = datetime.fromtimestamp(int(since))
-        until = cls.until(until)
-
-        changes = {
-            'time_checked': timestamp(until)
-        }
-
-        if not fields:
-            fields = cls.fields(request, 'tag_fields')
-        if not categories:
-            categories = cls.fields(request, 'tag_categories')
-
-        all_categories = ('author', 'epoch', 'kind', 'genre')
-        if categories:
-            categories = (c for c in categories if c in all_categories)
+        data = json.loads(request.POST.get('data'))
+        form = PictureImportForm(data)
+        if form.is_valid():
+            form.save()
+            return rc.CREATED

         else:
         else:

-            categories = all_categories
-
-        updated = []
-        deleted = []
-
-        for tag in Tag.objects.filter(category__in=categories, 
-                    changed_at__gte=since,
-                    changed_at__lt=until):
-            # only serve non-empty tags
-            if tag.get_count():
-                tag_d = cls.tag_dict(tag, fields)
-                updated.append(tag_d)
-            elif tag.created_at < since:
-                deleted.append(tag.id)
-        if updated:
-            changes['updated'] = updated
-
-        for tag in Deleted.objects.filter(category__in=categories,
-                content_type=Tag, 
-                    deleted_at__gte=since,
-                    deleted_at__lt=until,
-                    created_at__lt=since):
-            deleted.append(tag.id)
-        if deleted:
-            changes['deleted'] = deleted
-
-        return changes
-
-    @classmethod
-    def changes(cls, request=None, since=0, until=None, book_fields=None,
-                tag_fields=None, tag_categories=None):
-        until = cls.until(until)
-
-        changes = {
-            'time_checked': timestamp(until)
-        }
-
-        changes_by_type = {
-            'books': cls.book_changes(request, since, until, book_fields),
-            'tags': cls.tag_changes(request, since, until, tag_fields, tag_categories),
-        }
-
-        for model in changes_by_type:
-            for field in changes_by_type[model]:
-                if field == 'time_checked':
-                    continue
-                changes.setdefault(field, {})[model] = changes_by_type[model][field]
-        return changes
-
-
-class BookChangesHandler(CatalogueHandler):
-    allowed_methods = ('GET',)
-
-    def read(self, request, since):
-        return self.book_changes(request, since)
-
-
-class TagChangesHandler(CatalogueHandler):
-    allowed_methods = ('GET',)
-
-    def read(self, request, since):
-        return self.tag_changes(request, since)
-
-
-class ChangesHandler(CatalogueHandler):
-    allowed_methods = ('GET',)
-
-    def read(self, request, since):
-        return self.changes(request, since)
+            return rc.NOT_FOUND