From 3614e0656c357e27dec1dfdd5f538f4c6ecc4860 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Laura=20Kl=C3=BCnder?= <laura@codingcatgirl.de>
Date: Tue, 13 Sep 2016 21:03:43 +0200
Subject: [PATCH] cache api responses

---
 src/c3nav/api/views/cache.py   | 41 ++++++++++++++++++++++++++++++++++
 src/c3nav/api/views/mapdata.py |  7 +++---
 2 files changed, 45 insertions(+), 3 deletions(-)
 create mode 100644 src/c3nav/api/views/cache.py

diff --git a/src/c3nav/api/views/cache.py b/src/c3nav/api/views/cache.py
new file mode 100644
index 00000000..51b73021
--- /dev/null
+++ b/src/c3nav/api/views/cache.py
@@ -0,0 +1,41 @@
+import base64
+
+from django.core.cache import cache
+from django.utils.cache import patch_vary_headers
+
+from ..permissions import get_unlocked_packages
+
+
+class CachedViewSetMixin:
+    def get_cache_key(self, request):
+        cache_key = ('api__' + ('OPTIONS' if request.method == 'OPTIONS' else 'GET') + '_' +
+                     base64.b64encode(self.get_cache_params(request).encode()).decode() + '_' +
+                     request.path + '?' + request.META['QUERY_STRING'])
+        return cache_key
+
+    def get_cache_params(self, request):
+        return ''
+
+    def dispatch(self, request, *args, **kwargs):
+        do_cache = request.method in ('GET', 'HEAD', 'OPTIONS')
+        if do_cache:
+            cache_key = self.get_cache_key(request)
+            if cache_key in cache:
+                return cache.get(cache_key)
+        response = super().dispatch(request, *args, **kwargs)
+        patch_vary_headers(response, ['Cookie'])
+        if do_cache:
+            response.render()
+            cache.set(cache_key, response, 60)
+        return response
+
+    @property
+    def default_response_headers(self):
+        headers = super().default_response_headers
+        headers['Vary'] += ', Cookie'
+        return headers
+
+
+class AccessCachedViewSetMixin(CachedViewSetMixin):
+    def get_cache_params(self, request):
+        return super().get_cache_params(request)+'___'+'___'.join(get_unlocked_packages(request))
diff --git a/src/c3nav/api/views/mapdata.py b/src/c3nav/api/views/mapdata.py
index 27a18d8b..b2d6cc81 100644
--- a/src/c3nav/api/views/mapdata.py
+++ b/src/c3nav/api/views/mapdata.py
@@ -11,9 +11,10 @@ from rest_framework.viewsets import ReadOnlyModelViewSet
 from ...mapdata.models import Level, Package, Source
 from ..permissions import filter_source_queryset
 from ..serializers import LevelSerializer, PackageSerializer, SourceSerializer
+from .cache import AccessCachedViewSetMixin, CachedViewSetMixin
 
 
-class LevelViewSet(ReadOnlyModelViewSet):
+class LevelViewSet(CachedViewSetMixin, ReadOnlyModelViewSet):
     """
     Returns a list of all levels on the map.
     """
@@ -26,7 +27,7 @@ class LevelViewSet(ReadOnlyModelViewSet):
     search_fields = ('name',)
 
 
-class PackageViewSet(ReadOnlyModelViewSet):
+class PackageViewSet(AccessCachedViewSetMixin, ReadOnlyModelViewSet):
     """
     Returns a list of all packages the map consists of.
     """
@@ -39,7 +40,7 @@ class PackageViewSet(ReadOnlyModelViewSet):
     search_fields = ('name',)
 
 
-class SourceViewSet(ReadOnlyModelViewSet):
+class SourceViewSet(AccessCachedViewSetMixin, ReadOnlyModelViewSet):
     """
     Returns a list of source images (to use as a drafts).
     Call /sources/{name}/image to get the image.