Changeset 9188

Timestamp:

May 12, 2011, 1:19:43 PM (14 years ago)

Author:

rick

Message:

Show-case cache generation to avoid re-generation the pictures all the time.

Location:

src/django_gheat

Files:

• settings.py (modified) (3 diffs)
• website/tile.py (modified) (2 diffs)

src/django_gheat/settings.py

@@ -6 +6 @@
 DEBUG = True
 TEMPLATE_DEBUG = DEBUG
+
+# Required for Etags Caching Implementation
+USE_ETAGS = True
 
 ADMINS = (
@@ -23 +26 @@
     }
 }
+
+CACHES = {
+    'default': {
+        'BACKEND': 'django.core.cache.backends.locmem.LocMemCache',
+        'LOCATION': 'unique-snowflake'
+    }
+}
+
 
 # Local time zone for this installation. Choices can be found here:
@@ -97 +108 @@
 
 MIDDLEWARE_CLASSES = (
+    'django.middleware.cache.UpdateCacheMiddleware',
     'django.middleware.common.CommonMiddleware',
+    'django.middleware.cache.FetchFromCacheMiddleware',
+    'django.middleware.http.ConditionalGetMiddleware',
     'django.contrib.sessions.middleware.SessionMiddleware',
     'django.contrib.auth.middleware.AuthenticationMiddleware',

src/django_gheat/website/tile.py

@@ -4 +4 @@
 #
 # Rick van der Zwet <info@rickvanderzwet.nl>
+from django.core.cache import cache
 from django.core.management import setup_environ
 from django.db.models import Max
@@ -260 +261 @@
 # Create your views here.
 def serve_tile(request,zoom,x,y):
+  """
+  Showcase on caching and tile generation:
+
+  To make it 'easy' we use two types of caching here, memory cache expiring
+  at 30 seconds and database cache, always persistent storage on database.
+  """
+
   hash_key = TileCache.make_key("%s %s %s %s" % (zoom, x ,y, request.GET.urlencode()))
-  try:
-    d = TileCache.objects.get(key=hash_key)
-    data = d.data
-  except TileCache.DoesNotExist:
-    #log.setLevel(logging.DEBUG)
-    filter = {}
-    colour = (255,0,0)
-    for key, value in request.GET.iteritems():
-      if key == 'colour':
-        colour = tuple(map(int,value.split(',')))
-      else:
-        filter[key] = value
-    now = time.time()
-    im = make_tile(int(x),int(y),int(zoom),filter=filter,colour=colour)
-    log.info("Processing time: %s" % (time.time() - now))
-    data = im.get_image('png')
-    r = TileCache.objects.create(key=hash_key,data=data)
+  data = cache.get(hash_key)
+
+  if not data:
+    try:
+      d = TileCache.objects.get(key=hash_key)
+      data = d.data
+      cache.set(hash_key,data, 30)
+    except TileCache.DoesNotExist:
+      #log.setLevel(logging.DEBUG)
+      filter = {}
+      colour = (255,0,0)
+      for key, value in request.GET.iteritems():
+        if key == 'colour':
+          colour = tuple(map(int,value.split(',')))
+        else:
+          filter[key] = value
+      now = time.time()
+      im = make_tile(int(x),int(y),int(zoom),filter=filter,colour=colour)
+      log.info("Processing time: %s" % (time.time() - now))
+      data = im.get_image('png')
+      cache.set(hash_key,data, 30)
+      r = TileCache.objects.create(key=hash_key,data=data)
 
   response = HttpResponse(mimetype="image/png")