[odrs-web] odrs: Add caching support to fetch and ratings endpoints

[Richard Hughes <rhughes src gnome org>]

commit f077fe5b2e269ed4950513bd7b44df61146237f9
Author: Philip Withnall <withnall endlessm com>
Date:   Tue Aug 11 16:04:21 2020 +0100

    odrs: Add caching support to fetch and ratings endpoints
    
    Particularly with the ratings endpoint, this will allow users to avoid
    re-downloading all the ratings data if their local cache is up to date.
    
    Note that in production, this is already handled by the WSGI proxy
    layer. It helps to be explicit in the code about what caching is
    suitable for each endpoint, though.
    
    Signed-off-by: Philip Withnall <withnall endlessm com>

 app_data/odrs/views_api.py | 18 ++++++++++++------
 1 file changed, 12 insertions(+), 6 deletions(-)
---
diff --git a/app_data/odrs/views_api.py b/app_data/odrs/views_api.py
index 002e284..9527901 100644
--- a/app_data/odrs/views_api.py
+++ b/app_data/odrs/views_api.py
@@ -292,9 +292,12 @@ def api_fetch():
     items_new = items_new[start : start+limit]
 
     dat = json.dumps(items_new, sort_keys=True, indent=4, separators=(',', ': '))
-    return Response(response=dat,
-                    status=200, \
-                    mimetype='application/json')
+    response = Response(response=dat,
+                        status=200, \
+                        mimetype='application/json')
+    response.cache_control = 'private'
+    response.add_etag()
+    return response.make_conditional(request)
 
 @app.route('/1.0/reviews/api/moderate/<user_hash>')
 @app.route('/1.0/reviews/api/moderate/<user_hash>/<locale>')
@@ -518,6 +521,9 @@ def api_ratings():
         item[component.app_id] = ratings
 
     dat = json.dumps(item, sort_keys=True, indent=4, separators=(',', ': '))
-    return Response(response=dat,
-                    status=200, \
-                    mimetype='application/json')
+    response = Response(response=dat,
+                        status=200, \
+                        mimetype='application/json')
+    response.cache_control.public = True
+    response.add_etag()
+    return response.make_conditional(request)