diff options
Diffstat (limited to 'main')
| -rw-r--r-- | main/models.py | 6 | ||||
| -rw-r--r-- | main/utils.py | 42 |
2 files changed, 1 insertions, 47 deletions
diff --git a/main/models.py b/main/models.py index 09b1adc0..1b95f3fa 100644 --- a/main/models.py +++ b/main/models.py @@ -443,12 +443,8 @@ class PackageFile(models.Model): db_table = 'package_files' -# connect signals needed to keep cache in line with reality -from main.utils import refresh_latest -from django.db.models.signals import pre_save, post_save +from django.db.models.signals import pre_save -post_save.connect(refresh_latest, sender=Package, - dispatch_uid="main.models") # note: reporead sets the 'created' field on Package objects, so no signal # listener is set up here to do so pre_save.connect(set_created_field, sender=Donor, diff --git a/main/utils.py b/main/utils.py index 97cc540a..cf156566 100644 --- a/main/utils.py +++ b/main/utils.py @@ -12,11 +12,6 @@ from django.utils.timezone import now from django.template.defaultfilters import slugify -CACHE_TIMEOUT = 1800 -INVALIDATE_TIMEOUT = 10 -CACHE_LATEST_PREFIX = 'cache_latest_' - - def cache_function_key(func, args, kwargs): raw = [func.__name__, func.__module__, args, kwargs] pickled = pickle.dumps(raw, protocol=pickle.HIGHEST_PROTOCOL) @@ -76,43 +71,6 @@ def format_http_headers(request): make_choice = lambda l: [(str(m), str(m)) for m in l] -# These are in here because we would be jumping around in some import circles -# and hoops otherwise. The only thing currently using these keys is the feed -# caching stuff. - -def refresh_latest(**kwargs): - '''A post_save signal handler to clear out the cached latest value for a - given model.''' - cache_key = CACHE_LATEST_PREFIX + kwargs['sender'].__name__ - # We could delete the value, but that could open a race condition - # where the new data wouldn't have been committed yet by the calling - # thread. Instead, explicitly set it to None for a short amount of time. - # Hopefully by the time it expires we will have committed, and the cache - # will be valid again. See "Scaling Django" by Mike Malone, slide 30. - cache.set(cache_key, None, INVALIDATE_TIMEOUT) - - -def retrieve_latest(sender, latest_by=None): - # we could break this down based on the request url, but it would probably - # cost us more in query time to do so. - cache_key = CACHE_LATEST_PREFIX + sender.__name__ - latest = cache.get(cache_key) - if latest: - return latest - try: - if latest_by is None: - latest_by = sender._meta.get_latest_by - latest = sender.objects.values(latest_by).latest(latest_by)[latest_by] - # Using add means "don't overwrite anything in there". What could be in - # there is an explicit None value that our refresh signal set, which - # means we want to avoid race condition possibilities for a bit. - cache.add(cache_key, latest, CACHE_TIMEOUT) - return latest - except sender.DoesNotExist: - pass - return None - - def set_created_field(sender, **kwargs): '''This will set the 'created' field on any object to the current UTC time if it is unset. |