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Simple upgrades.
[wolnelektury.git] / apps / api / handlers.py
diff --git a/apps/api/handlers.py b/apps/api/handlers.py
index d34806f..e1792af 100644 (file)
--- a/apps/api/handlers.py
+++ b/apps/api/handlers.py
@@ -1,26 +1,33 @@
 # -*- 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.
-
+#
 from datetime import datetime, timedelta
 import json
 
 from django.conf import settings
 from django.contrib.sites.models import Site
 from datetime import datetime, timedelta
 import json
 
 from django.conf import settings
 from django.contrib.sites.models import Site
+from django.core.cache import get_cache
 from django.core.urlresolvers import reverse
 from django.core.urlresolvers import reverse
+from django.utils.functional import lazy
+from django.utils.timezone import utc
 from piston.handler import AnonymousBaseHandler, BaseHandler
 from piston.utils import rc
 from piston.handler import AnonymousBaseHandler, BaseHandler
 from piston.utils import rc
+from sorl.thumbnail import default
 
 from api.helpers import timestamp
 from api.models import Deleted
 from catalogue.forms import BookImportForm
 
 from api.helpers import timestamp
 from api.models import Deleted
 from catalogue.forms import BookImportForm
-from catalogue.models import Book, Tag, BookMedia, Fragment
+from catalogue.models import Book, Tag, BookMedia, Fragment, Collection
+from catalogue.utils import related_tag_name
 from picture.models import Picture
 from picture.forms import PictureImportForm
 from picture.models import Picture
 from picture.forms import PictureImportForm
+from wolnelektury.utils import tz
 
 from stats.utils import piwik_track
 
 
 from stats.utils import piwik_track
 
-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 = {
@@ -31,10 +38,13 @@ 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.
 
 def read_tags(tags, allowed):
     """ Reads a path of filtering tags.
@@ -78,7 +88,7 @@ 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):
@@ -86,57 +96,87 @@ 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', '')
+
+
+class BookDetails(object):
+    """Custom fields used for representing Books."""
+
+    @classmethod
+    def href(cls, book):
+        """ Returns an URI for a Book in the API. """
+        return API_BASE + reverse("api_book", args=[book.slug])
 
 
-    Responsible for lists of Book objects
-    and fields used for representing Books.
+    @classmethod
+    def url(cls, book):
+        """ Returns Book's URL on the site. """
+
+        return WL_BASE + book.get_absolute_url()
 
 
+    @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()
+
+    @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.
+
+    Responsible for single Book details.
     """
     allowed_methods = ['GET']
     """
     allowed_methods = ['GET']
-    fields = ['title', 'parent'] + Book.formats + [
-        'media', 'url'] + category_singular.keys()
+    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. """
 
     @piwik_track
     def read(self, request, book):
         """ Returns details of a book, identified by a slug and lang. """
-        kwargs = Book.split_urlid(book)
-        if not kwargs:
-            return rc.NOT_FOUND
-
         try:
         try:
-            return Book.objects.get(**kwargs)
+            return Book.objects.get(slug=book)
         except Book.DoesNotExist:
             return rc.NOT_FOUND
 
 
         except Book.DoesNotExist:
             return rc.NOT_FOUND
 
 
-class AnonymousBooksHandler(AnonymousBaseHandler):
+class AnonymousBooksHandler(AnonymousBaseHandler, 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 lists of Book objects.
     """
     allowed_methods = ('GET',)
     model = Book
     """
     allowed_methods = ('GET',)
     model = Book
-    fields = ['href', 'title']
-
-    categories = set(['author', 'epoch', 'kind', 'genre'])
-
-    @classmethod
-    def href(cls, book):
-        """ Returns an URI for a Book in the API. """
-        return API_BASE + reverse("api_book", args=[book.urlid()])
+    fields = book_tag_categories + ['href', 'title', 'url', 'cover', 'cover_thumb']
 
     @classmethod
 
     @classmethod
-    def url(cls, book):
-        """ Returns Book's URL on the site. """
-
-        return WL_BASE + book.get_absolute_url()
+    def genres(cls, book):
+        """ Returns all media for a book. """
+        return book.tags.filter(category='genre')
 
     @piwik_track
 
     @piwik_track
-    def read(self, request, tags, top_level=False):
+    def read(self, request, tags, top_level=False,
+                audiobooks=False, daisy=False):
         """ 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
@@ -145,7 +185,11 @@ class AnonymousBooksHandler(AnonymousBaseHandler):
              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)
+        try:
+            tags = read_tags(tags, allowed=book_tag_categories)
+        except ValueError:
+            return rc.NOT_FOUND
+
         if tags:
             if top_level:
                 books = Book.tagged_top_level(tags)
         if tags:
             if top_level:
                 books = Book.tagged_top_level(tags)
@@ -155,27 +199,29 @@ class AnonymousBooksHandler(AnonymousBaseHandler):
         else:
             books = Book.objects.all()
 
         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:
             return rc.NOT_FOUND
 
         if books.exists():
             return books
         else:
             return rc.NOT_FOUND
 
-    def create(self, request, tags, top_level=False):
-        return 'aaa'
-
-    @classmethod
-    def media(self, book):
-        """ Returns all media for a book. """
-
-        return book.media.all()
+    def create(self, request, *args, **kwargs):
+        return rc.FORBIDDEN
 
 
 
 
-class BooksHandler(BaseHandler):
+class BooksHandler(BookDetailHandler):
+    allowed_methods = ('GET', 'POST')
     model = Book
     model = Book
-    fields = ('slug', 'title')
+    fields = book_tag_categories + ['href', 'title', 'url', 'cover', 'cover_thumb']
     anonymous = AnonymousBooksHandler
 
     anonymous = AnonymousBooksHandler
 
-    def create(self, request, tags, top_level=False):
+    def create(self, request, *args, **kwargs):
         if not request.user.has_perm('catalogue.add_book'):
             return rc.FORBIDDEN
 
         if not request.user.has_perm('catalogue.add_book'):
             return rc.FORBIDDEN
 
@@ -187,14 +233,25 @@ class BooksHandler(BaseHandler):
         else:
             return rc.NOT_FOUND
 
         else:
             return rc.NOT_FOUND
 
+
+class EBooksHandler(AnonymousBooksHandler):
+    fields = ('author', 'href', 'title', 'cover') + tuple(Book.ebook_formats)
+
+
 # add categorized tags fields for Book
 def _tags_getter(category):
     @classmethod
     def get_tags(cls, book):
         return book.tags.filter(category=category)
     return get_tags
 # add categorized tags fields for Book
 def _tags_getter(category):
     @classmethod
     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(related_tag_name(t) for t in book.related_info()['tags'].get(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):
@@ -208,13 +265,74 @@ def _file_getter(format):
             return ''
     return get_file
 for format in Book.formats:
             return ''
     return get_file
 for format in Book.formats:
-    setattr(BooksHandler, format, _file_getter(format))
+    setattr(BookDetails, format, _file_getter(format))
+
+
+class CollectionDetails(object):
+    """Custom Collection fields."""
+
+    @classmethod
+    def href(cls, collection):
+        """ Returns URI in the API for the collection. """
+
+        return API_BASE + reverse("api_collection", args=[collection.slug])
+
+    @classmethod
+    def url(cls, collection):
+        """ Returns URL on the site. """
+
+        return WL_BASE + collection.get_absolute_url()
+
+    @classmethod
+    def books(cls, collection):
+        return Book.objects.filter(collection.get_query())
 
 
 
 
-class TagDetailHandler(BaseHandler):
+
+class CollectionDetailHandler(BaseHandler, CollectionDetails):
+    allowed_methods = ('GET',)
+    fields = ['url', 'title', 'description', 'books']
+
+    @piwik_track
+    def read(self, request, slug):
+        """ Returns details of a collection, identified by slug. """
+        try:
+            return Collection.objects.get(slug=slug)
+        except Collection.DoesNotExist:
+            return rc.NOT_FOUND
+
+
+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):
+        """ Returns URI in the API for the tag. """
+
+        return API_BASE + reverse("api_tag", args=[category_plural[tag.category], tag.slug])
+
+    @classmethod
+    def url(cls, tag):
+        """ Returns URL on the site. """
+
+        return WL_BASE + tag.get_absolute_url()
+
+
+class TagDetailHandler(BaseHandler, TagDetails):
     """ Responsible for details of a single Tag object. """
 
     """ Responsible for details of a single Tag object. """
 
-    fields = ['name', 'sort_key', 'description']
+    fields = ['name', 'url', 'sort_key', 'description']
 
     @piwik_track
     def read(self, request, category, slug):
 
     @piwik_track
     def read(self, request, category, slug):
@@ -231,7 +349,7 @@ class TagDetailHandler(BaseHandler):
             return rc.NOT_FOUND
 
 
             return rc.NOT_FOUND
 
 
-class TagsHandler(BaseHandler):
+class TagsHandler(BaseHandler, TagDetails):
     """ Main handler for Tag objects.
 
     Responsible for lists of Tag objects
     """ Main handler for Tag objects.
 
     Responsible for lists of Tag objects
@@ -240,7 +358,7 @@ class TagsHandler(BaseHandler):
     """
     allowed_methods = ('GET',)
     model = Tag
     """
     allowed_methods = ('GET',)
     model = Tag
-    fields = ['name', 'href']
+    fields = ['name', 'href', 'url']
 
     @piwik_track
     def read(self, request, category):
 
     @piwik_track
     def read(self, request, category):
@@ -258,34 +376,42 @@ class TagsHandler(BaseHandler):
             return rc.NOT_FOUND
 
 
             return rc.NOT_FOUND
 
 
+class FragmentDetails(object):
+    """Custom Fragment fields."""
+
     @classmethod
     @classmethod
-    def href(cls, tag):
-        """ Returns URI in the API for the tag. """
+    def href(cls, fragment):
+        """ Returns URI in the API for the fragment. """
 
 
-        return API_BASE + reverse("api_tag", args=[category_plural[tag.category], tag.slug])
+        return API_BASE + reverse("api_fragment",
+            args=[fragment.book.slug, fragment.anchor])
+
+    @classmethod
+    def url(cls, fragment):
+        """ Returns URL on the site for the fragment. """
 
 
+        return WL_BASE + fragment.get_absolute_url()
+
+    @classmethod
+    def themes(cls, fragment):
+        """ Returns a list of theme tags for the fragment. """
 
 
-class FragmentDetailHandler(BaseHandler):
+        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. """
     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. """
-        kwargs = Book.split_urlid(book)
-        if not kwargs:
-            return rc.NOT_FOUND
-
-        fragment_kwargs = {}
-        for field, value in kwargs.items():
-            fragment_kwargs['book__' + field] = value
-
         try:
         try:
-            return Fragment.objects.get(anchor=anchor, **fragment_kwargs)
+            return Fragment.objects.get(book__slug=book, anchor=anchor)
         except Fragment.DoesNotExist:
             return rc.NOT_FOUND
 
 
         except Fragment.DoesNotExist:
             return rc.NOT_FOUND
 
 
-class FragmentsHandler(BaseHandler):
+class FragmentsHandler(BaseHandler, FragmentDetails):
     """ Main handler for Fragments.
 
     Responsible for lists of Fragment objects
     """ Main handler for Fragments.
 
     Responsible for lists of Fragment objects
@@ -293,7 +419,7 @@ class FragmentsHandler(BaseHandler):
 
     """
     model = Fragment
 
     """
     model = Fragment
-    fields = ['book', 'anchor', 'href']
+    fields = ['book', 'url', 'anchor', 'href']
     allowed_methods = ('GET',)
 
     categories = set(['author', 'epoch', 'kind', 'genre', 'book', 'theme'])
     allowed_methods = ('GET',)
 
     categories = set(['author', 'epoch', 'kind', 'genre', 'book', 'theme'])
@@ -306,32 +432,16 @@ class FragmentsHandler(BaseHandler):
              books/book-slug/authors/an-author/themes/a-theme/
 
         """
              books/book-slug/authors/an-author/themes/a-theme/
 
         """
-        tags = read_tags(tags, allowed=self.categories)
+        try:
+            tags = 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:
             return rc.NOT_FOUND
 
         fragments = Fragment.tagged.with_all(tags).select_related('book')
         if fragments.exists():
             return fragments
         else:
             return rc.NOT_FOUND
 
-    @classmethod
-    def href(cls, fragment):
-        """ Returns URI in the API for the fragment. """
-
-        return API_BASE + reverse("api_fragment", args=[fragment.book.urlid(), fragment.anchor])
-
-    @classmethod
-    def url(cls, fragment):
-        """ Returns URL on the site for the fragment. """
-
-        return WL_BASE + fragment.get_absolute_url()
-
-    @classmethod
-    def themes(cls, fragment):
-        """ Returns a list of theme tags for the fragment. """
-
-        return fragment.tags.filter(category='theme')
-
-
 
 
 # Changes handlers
 
 
 # Changes handlers
@@ -357,7 +467,7 @@ class CatalogueHandler(BaseHandler):
         """
         # set to five minutes ago, to avoid concurrency issues
         if t is None:
         """
         # set to five minutes ago, to avoid concurrency issues
         if t is None:
-            t = datetime.now() - timedelta(seconds=settings.API_WAIT)
+            t = datetime.utcnow().replace(tzinfo=utc) - timedelta(seconds=settings.API_WAIT)
         # set to whole second in case DB supports something smaller
         return t.replace(microsecond=0)
 
         # set to whole second in case DB supports something smaller
         return t.replace(microsecond=0)
 
@@ -365,7 +475,7 @@ class CatalogueHandler(BaseHandler):
     def book_dict(book, fields=None):
         all_fields = ['url', 'title', 'description',
                       'gazeta_link', 'wiki_link',
     def book_dict(book, fields=None):
         all_fields = ['url', 'title', 'description',
                       'gazeta_link', 'wiki_link',
-                      ] + Book.formats + BookMedia.formats + [
+                      ] + Book.formats + BookMedia.formats.keys() + [
                       'parent', 'parent_number',
                       'tags',
                       'license', 'license_description', 'source_name',
                       'parent', 'parent_number',
                       'tags',
                       'license', 'license_description', 'source_name',
@@ -377,7 +487,7 @@ class CatalogueHandler(BaseHandler):
         else:
             fields = all_fields
 
         else:
             fields = all_fields
 
-        extra_info = book.get_extra_info_value()
+        extra_info = book.extra_info
 
         obj = {}
         for field in fields:
 
         obj = {}
         for field in fields:
@@ -392,7 +502,7 @@ class CatalogueHandler(BaseHandler):
 
             elif field in BookMedia.formats:
                 media = []
 
             elif field in BookMedia.formats:
                 media = []
-                for m in book.media.filter(type=field):
+                for m in book.media.filter(type=field).iterator():
                     media.append({
                         'url': m.file.url,
                         'size': m.file.size,
                     media.append({
                         'url': m.file.url,
                         'size': m.file.size,
@@ -404,10 +514,10 @@ class CatalogueHandler(BaseHandler):
                 obj[field] = book.get_absolute_url()
 
             elif field == 'tags':
                 obj[field] = book.get_absolute_url()
 
             elif field == 'tags':
-                obj[field] = [t.id for t in book.tags.exclude(category__in=('book', 'set'))]
+                obj[field] = [t.id for t in book.tags.exclude(category__in=('book', 'set')).iterator()]
 
             elif field == 'author':
 
             elif field == 'author':
-                obj[field] = ", ".join(t.name for t in book.tags.filter(category='author'))
+                obj[field] = ", ".join(t.name for t in book.tags.filter(category='author').iterator())
 
             elif field == 'parent':
                 obj[field] = book.parent_id
 
             elif field == 'parent':
                 obj[field] = book.parent_id
@@ -428,7 +538,7 @@ class CatalogueHandler(BaseHandler):
 
     @classmethod
     def book_changes(cls, request=None, since=0, until=None, fields=None):
 
     @classmethod
     def book_changes(cls, request=None, since=0, until=None, fields=None):
-        since = datetime.fromtimestamp(int(since))
+        since = datetime.fromtimestamp(int(since), tz)
         until = cls.until(until)
 
         changes = {
         until = cls.until(until)
 
         changes = {
@@ -444,16 +554,16 @@ class CatalogueHandler(BaseHandler):
 
         last_change = since
         for book in Book.objects.filter(changed_at__gte=since,
 
         last_change = since
         for book in Book.objects.filter(changed_at__gte=since,
-                    changed_at__lt=until):
+                    changed_at__lt=until).iterator():
             book_d = cls.book_dict(book, fields)
             updated.append(book_d)
         if updated:
             changes['updated'] = updated
 
             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, 
+        for book in Deleted.objects.filter(content_type=Book,
                     deleted_at__gte=since,
                     deleted_at__lt=until,
                     deleted_at__gte=since,
                     deleted_at__lt=until,
-                    created_at__lt=since):
+                    created_at__lt=since).iterator():
             deleted.append(book.id)
         if deleted:
             changes['deleted'] = deleted
             deleted.append(book.id)
         if deleted:
             changes['deleted'] = deleted
@@ -479,7 +589,7 @@ class CatalogueHandler(BaseHandler):
                 obj[field] = tag.get_absolute_url()
 
             elif field == 'books':
                 obj[field] = tag.get_absolute_url()
 
             elif field == 'books':
-                obj[field] = [b.id for b in Book.tagged_top_level([tag])]
+                obj[field] = [b.id for b in Book.tagged_top_level([tag]).iterator()]
 
             elif field == 'sort_key':
                 obj[field] = tag.sort_key
 
             elif field == 'sort_key':
                 obj[field] = tag.sort_key
@@ -494,7 +604,7 @@ class CatalogueHandler(BaseHandler):
 
     @classmethod
     def tag_changes(cls, request=None, since=0, until=None, fields=None, categories=None):
 
     @classmethod
     def tag_changes(cls, request=None, since=0, until=None, fields=None, categories=None):
-        since = datetime.fromtimestamp(int(since))
+        since = datetime.fromtimestamp(int(since), tz)
         until = cls.until(until)
 
         changes = {
         until = cls.until(until)
 
         changes = {
@@ -515,9 +625,9 @@ class CatalogueHandler(BaseHandler):
         updated = []
         deleted = []
 
         updated = []
         deleted = []
 
-        for tag in Tag.objects.filter(category__in=categories, 
+        for tag in Tag.objects.filter(category__in=categories,
                     changed_at__gte=since,
                     changed_at__gte=since,
-                    changed_at__lt=until):
+                    changed_at__lt=until).iterator():
             # only serve non-empty tags
             if tag.book_count:
                 tag_d = cls.tag_dict(tag, fields)
             # only serve non-empty tags
             if tag.book_count:
                 tag_d = cls.tag_dict(tag, fields)
@@ -528,10 +638,10 @@ class CatalogueHandler(BaseHandler):
             changes['updated'] = updated
 
         for tag in Deleted.objects.filter(category__in=categories,
             changes['updated'] = updated
 
         for tag in Deleted.objects.filter(category__in=categories,
-                content_type=Tag, 
+                content_type=Tag,
                     deleted_at__gte=since,
                     deleted_at__lt=until,
                     deleted_at__gte=since,
                     deleted_at__lt=until,
-                    created_at__lt=since):
+                    created_at__lt=since).iterator():
             deleted.append(tag.id)
         if deleted:
             changes['deleted'] = deleted
             deleted.append(tag.id)
         if deleted:
             changes['deleted'] = deleted
@@ -542,6 +652,16 @@ class CatalogueHandler(BaseHandler):
     def changes(cls, request=None, since=0, until=None, book_fields=None,
                 tag_fields=None, tag_categories=None):
         until = cls.until(until)
     def changes(cls, request=None, since=0, until=None, book_fields=None,
                 tag_fields=None, tag_categories=None):
         until = cls.until(until)
+        since = int(since)
+
+        if not since:
+            cache = get_cache('api')
+            key = hash((book_fields, tag_fields, tag_categories,
+                    tuple(sorted(request.GET.items()))
+                  ))
+            value = cache.get(key)
+            if value is not None:
+                return value
 
         changes = {
             'time_checked': timestamp(until)
 
         changes = {
             'time_checked': timestamp(until)
@@ -557,6 +677,10 @@ class CatalogueHandler(BaseHandler):
                 if field == 'time_checked':
                     continue
                 changes.setdefault(field, {})[model] = changes_by_type[model][field]
                 if field == 'time_checked':
                     continue
                 changes.setdefault(field, {})[model] = changes_by_type[model][field]
+
+        if not since:
+            cache.set(key, changes)
+
         return changes
 
 
         return changes