Add cloudflare purging to homepage

home/__init__.py

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+default_app_config = 'home.apps.HomeConfig'

home/apps.py

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+from django.apps import AppConfig
+
+
+class HomeConfig(AppConfig):
+    name = 'home'
+
+    def ready(self):
+        import home.signals # noqa: F401

home/signals.py

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+from django.db.models.signals import post_save, post_delete
+
+from wagtail.contrib.wagtailfrontendcache.utils import purge_page_from_cache
+
+from home.models import HomePage
+from github.models import Release
+from blog.models import BlogPage
+from directory.models import DirectoryEntry
+
+
+def purge_homepage_from_frontend_cache(sender, **kwargs):
+    for home_page in HomePage.objects.live():
+        purge_page_from_cache(home_page)
+
+
+post_save.connect(purge_homepage_from_frontend_cache, sender=Release)
+post_save.connect(purge_homepage_from_frontend_cache, sender=BlogPage)
+post_save.connect(purge_homepage_from_frontend_cache, sender=DirectoryEntry)
+post_delete.connect(purge_homepage_from_frontend_cache, sender=Release)
+post_delete.connect(purge_homepage_from_frontend_cache, sender=BlogPage)
+post_delete.connect(purge_homepage_from_frontend_cache, sender=DirectoryEntry)

home/tests/test_frontendcache_purging.py

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+import datetime
+
+from unittest.mock import patch, call
+
+from django.test import TestCase
+
+from home.tests.factories import HomePageFactory
+from github.models import Release
+from blog.tests.factories import BlogPageFactory
+from directory.tests.factories import DirectoryEntryFactory
+
+
+@patch('home.signals.purge_page_from_cache')
+class FrontendCacheTestCase(TestCase):
+    def setUp(self):
+        self.home_page = HomePageFactory()
+
+    def test_cache_purged_for_release(self, purge_mock):
+        "Homepage cache should be purged when a new release is added"
+        Release.objects.create(date=datetime.datetime(2016, 1, 1, 0, 0, 0))
+        purge_mock.assert_called_once_with(self.home_page)
+
+    def test_cache_purged_for_blog_post(self, purge_mock):
+        "Homepage cache should be purged when a new blog post is added"
+        BlogPageFactory.create()
+        purge_mock.assert_called_once_with(self.home_page)
+
+    def test_cache_purged_for_directory_entry(self, purge_mock):
+        "Homepage cache should be purged when a new directory entry is added"
+        DirectoryEntryFactory.create()
+        # DirectoryEntry saving logic causes it to be saved twice, triggering
+        # the purge twice (this is not necessarily desireable, but it is
+        # mostly harmless)
+        purge_mock.assert_has_calls([
+            call(self.home_page), call(self.home_page)
+        ])