Allow purging of subpaths of pages

wagtail/contrib/wagtailfrontendcache/utils.py

@@ -25,9 +25,11 @@ class CustomHTTPAdapter(HTTPAdapter):
 
 
 def purge_page_from_cache(page):
+    # Get session
     varnish_url = getattr(settings, 'WAGTAILFRONTENDCACHE_LOCATION', 'http://127.0.0.1:8000/')
-
-    # Purge
     session = requests.Session()
     session.mount('http://', CustomHTTPAdapter(varnish_url))
-    session.request('PURGE', page.full_url)
+
+    # Purge paths from cache
+    for path in page.get_cached_paths():
+        session.request('PURGE', page.full_url + path[1:])

wagtail/wagtailcore/models.py

@@ -629,13 +629,27 @@ class Page(MP_Node, ClusterableModel, Indexed):
         """
         return self.serve(self.dummy_request())
 
+    def get_internal_paths(self):
+        """
+        This returns a list of paths within this page.
+        This is used for static sites, sitemaps and cache invalidation.
+        """
+        return ['/']
+
+    def get_cached_paths(self):
+        """
+        This returns a list of paths to invalidate in a frontend cache
+        """
+        return self.get_internal_paths()
+
     def get_static_site_paths(self):
         """
         This is a generator of URL paths to feed into a static site generator
         Override this if you would like to create static versions of subpages
         """
-        # Yield paths for this page
-        yield '/'
+       # Yield paths for this page
+        for url in self.get_internal_paths():
+            yield url
 
         # Yield paths for child pages
         for child in self.get_children().live():