From 13b457c4409fc536b83556d9258fb880d149bdd8 Mon Sep 17 00:00:00 2001
From: yackob03 <jacob.moshenko@gmail.com>
Date: Sun, 20 Oct 2013 01:18:31 -0400
Subject: [PATCH] Add caching to the changes api since it is so expensive and
 can return large results.

---
 endpoints/api.py |  2 ++
 util/cache.py    | 12 ++++++++++++
 2 files changed, 14 insertions(+)
 create mode 100644 util/cache.py

diff --git a/endpoints/api.py b/endpoints/api.py
index edb49aa0e..e2229d81b 100644
--- a/endpoints/api.py
+++ b/endpoints/api.py
@@ -20,6 +20,7 @@ from auth.permissions import (ReadRepositoryPermission,
                               AdministerRepositoryPermission)
 from endpoints import registry
 from endpoints.web import common_login
+from util.cache import cache_control
 
 
 store = storage.load()
@@ -380,6 +381,7 @@ def get_image(namespace, repository, image_id):
 
 @app.route('/api/repository/<path:repository>/image/<image_id>/changes',
            methods=['GET'])
+@cache_control(max_age=60*60)  # Cache for one hour
 @parse_repository_name
 def get_image_changes(namespace, repository, image_id):
   permission = ReadRepositoryPermission(namespace, repository)
diff --git a/util/cache.py b/util/cache.py
new file mode 100644
index 000000000..96160a71e
--- /dev/null
+++ b/util/cache.py
@@ -0,0 +1,12 @@
+from functools import wraps
+
+
+def cache_control(max_age=55):
+  def wrap(f):
+    @wraps(f)
+    def add_max_age(*args, **kwargs):
+      response = f(*args, **kwargs)
+      response.headers['Cache-Control'] = 'max-age=%d' % max_age
+      return response
+    return add_max_age
+  return wrap