Add some caching using Redis

util.py

@@ -1,11 +1,48 @@
 import datetime
+import os
 import random
 import re
-from functools import wraps
+import time
+from functools import wraps, update_wrapper
 
 from flask import abort
 from flask_login import current_user, login_required
 from passlib.hash import bcrypt
+from redis import from_url
+
+redis = from_url(os.getenv("REDIS_URL"))
+
+
+def cache(expire_in=120, uid=None):
+    def decorator(f):
+        def cache_function(*args, **kwargs):
+            arg_collection = list(args) + sorted(kwargs.items())
+            key = 'cache/%s/%s' % (f.__name__, arg_collection)
+            if uid is not None:
+                key = '%s/%s' % (key, uid())
+            with redis.pipeline() as p:
+                p.get(key)
+                result = p.execute()[0]
+                if result is None:
+                    result = f(*args, **kwargs)
+                    p.set(key, result)
+                    p.expireat(key, int(time.time() + expire_in))
+                    p.execute()
+            return result
+
+        return update_wrapper(cache_function, f)
+
+    return decorator
+
+
+def uncache(function_name=None, args=None, uid=None):
+    if not function_name: return
+    key = 'cache/%s/%s' % (function_name, args)
+    if uid is not None:
+        key = '%s/%s' % (key, uid)
+    with redis.pipeline() as p:
+        p.delete(key)
+        p.execute()
 
 
 def isoformat(seconds):

views/events.py

@@ -7,7 +7,7 @@
 import config
 from forms import EventForm
 from models import db, Event
-from util import admin_required, isoformat
+from util import admin_required, isoformat, cache, uncache
 
 blueprint = Blueprint('events', __name__, template_folder='templates')
 
@@ -21,6 +21,7 @@ def events_create():
         event_create_form.populate_obj(new_event)
         db.session.add(new_event)
         db.session.commit()
+        uncache(function_name=events_owned.__name__, args=[], uid=current_user.id)
         return redirect(url_for('.events_owned'))
     return render_template('events/create.html', event_create_form=event_create_form)
 
@@ -139,6 +140,7 @@ def events_unapproved(page_number=1):
 
 @blueprint.route('/owned')
 @blueprint.route('/owned/page/<int:page_number>')
+@cache(uid=lambda: current_user.id)
 @login_required
 def events_owned(page_number=1):
     if page_number <= 0:
@@ -199,5 +201,6 @@ def events_remove(event_id):
     if current_user != event.owner:
         abort(403)
     event.removed = True
+    uncache(function_name=events_owned.__name__, args=[], uid=current_user.id)
     db.session.commit()
     return redirect(url_for('.events_owned'))