Purge old absolute_urls of a model when model instance is updated.

.gitignore

@@ -0,0 +1,3 @@
+
+django_varnish.egg-info/*
+*.pyc

setup.py

@@ -2,7 +2,7 @@
 
 setup(
     name = "django-varnish",
-    version = '0.1',
+    version = '0.1.2',
     url = 'http://opensource.washingtontimes.com/projects/django-varnish/',
     author = 'Justin Quick',
     author_email= 'justquick@gmail.com',

varnishapp/manager.py

@@ -3,4 +3,6 @@
 from atexit import register
 
 manager = VarnishManager(getattr(settings, 'VARNISH_MANAGEMENT_ADDRS', ()))
-register(manager.close)
+register(manager.close)
+
+from signals import *

varnishapp/signals.py

@@ -3,9 +3,87 @@
 from django.conf import settings
 from manager import manager
 
+import logging
+
+logger = logging.getLogger("varnish.invalidation")
+
+
+def purge_old_paths(abs_url):
+
+    """
+    If Django redirects app is installed, search for new paths based on given absolute url 
+    and purge all the corresponding old paths to ensure the user gets a redirect to the 
+    new path and not an old cached version of the page if i.e. the slug has changed.
+    """
+
+    if "django.contrib.redirects" in settings.INSTALLED_APPS:
+        from django.contrib.redirects.models import Redirect
+
+        oldpaths = Redirect.objects.filter(new_path=abs_url)
+
+        for p in oldpaths:
+
+             try:
+                 resp = manager.run('ban.url', r'^%s$' % str(p.old_path))
+             except:
+                 logger.warn('No varnish instance running. Could not purge %s' % str(p.old_path))
 
 def absolute_url_purge_handler(sender, **kwargs):
-    manager.run('purge.url', r'^%s$' % kwargs['instance'].get_absolute_url())
+    """
+    Purges the absolute url of the model instance
+    NB: It adds $ to the end of the purge, so no urls with parameters etc are purged, 
+    only the url given by get_absolute_url itself
+    """
+    instance = kwargs['instance']
+
+    if hasattr(instance, 'get_absolute_url'):
+        abs_url = instance.get_absolute_url()
+
+        try:
+            banurl = r'^%s$' % abs_url
+            logger.info("Banning %s" % banurl)
+            resp = manager.run('ban.url', banurl)
+            logger.info(resp)
+        except:
+            logger.warn('No varnish instance running. Could not purge %s ' % abs_url)
+
+        purge_old_paths(abs_url)
+
+for model in getattr(settings, 'VARNISH_WATCHED_MODELS', ()):
+    post_save.connect(absolute_url_purge_handler, sender=get_model(*model.split('.')))
+
+
+
 
+def api_resource_purge_handler (sender, **kwargs):
+
+    """
+    Purges object urls in the API. Requires a get_resource_url on the model that
+    returns the url of the api resource object base url. If using tastypie that would 
+    look like something like this on a resource named person:
+
+    @models.permalink
+    def get_resource_url(self):
+           return ('api_dispatch_detail', (), {
+                                               'resource_name': 'person', 
+                                                'api_name': 'v1',
+                                                'pk': self.id}) 
+
+    The method will purge all urls *starting* with the url  
+
+    """
+    instance = kwargs['instance']
+
+    if hasattr(instance, 'get_resource_url'):
+        resource_url = instance.get_resource_url()
+
+        try:
+            manager.run('ban.url', r'^%s' % resource_url)
+        except:
+            logger.warn('No varnish instance running. Could not purge %s ' % resource_url)
+
+        purge_old_paths(resource_url)
+
+
 for model in getattr(settings, 'VARNISH_WATCHED_MODELS', ()):
-    post_save.connect(absolute_url_purge_handler, sender=get_model(*model.split('.')))
+    post_save.connect(api_resource_purge_handler, sender=get_model(*model.split('.')))