Clear the resource viewlet cache when changing the resource registry …

…or activating an add-on.

This avoids needing a restart before seeing changes when you run in production mode.
Fixes [issue 3505](#3505).

Products/CMFPlone/controlpanel/browser/resourceregistry.py

@@ -2,6 +2,7 @@
 from plone.base import PloneMessageFactory as _
 from plone.base.interfaces import IBundleRegistry
 from plone.registry.interfaces import IRegistry
+from Products.CMFPlone.resources.browser.resource import clear_resource_viewlet_caches
 from Products.Five.browser import BrowserView
 from Products.statusmessages.interfaces import IStatusMessage
 from zope.component import getUtility
@@ -149,4 +150,5 @@ def process_form(self):
             self._switch_cache(False)
         else:
             raise ValueError("Invalid form data")
+        clear_resource_viewlet_caches()
         self.request.response.redirect(self.request["ACTUAL_URL"])

Products/CMFPlone/resources/browser/resource.py

@@ -19,7 +19,7 @@
 logger = logging.getLogger(__name__)
 
 REQUEST_CACHE_KEY = "_WEBRESOURCE_CACHE_"
-
+SITE_ROOT_CACHE_KEY_PREFIX = "_v_rendered_cache_"
 GRACEFUL_DEPENDENCY_REWRITE = {
     "plone-base": "plone",
     "plone-legacy": "plone",
@@ -59,7 +59,7 @@ def _cache_attr_name(self, site):
         for bundle in e_bundles | d_bundles:
             hashtool.update(bundle.encode('utf8'))
         hashtool.update(self._user_local_roles(site).encode("utf8"))
-        return f"_v_renderend_cache_{hashtool.hexdigest()}"
+        return f"{SITE_ROOT_CACHE_KEY_PREFIX}{hashtool.hexdigest()}"
 
     @property
     def _rendered_cache(self):
@@ -313,3 +313,26 @@ def index(self):
             rendered = self.renderer["css"].render()
             self._rendered_cache = rendered
         return rendered
+
+
+def clear_resource_viewlet_caches():
+    """Remove volatile cache of resource viewlets.
+
+    See discussion in https://github.com/plone/Products.CMFPlone/issues/3505
+    """
+    site = getSite()
+
+    # I don't trust removing keys from a dict when iterating over this dict,
+    # so gather them in a list first.
+    to_remove = [
+        name for name in site.__dict__
+        if name.startswith(SITE_ROOT_CACHE_KEY_PREFIX)
+    ]
+    for name in to_remove:
+        # The attribute is volatile, meaning it may disappear at any time,
+        # so we catch errors.
+        try:
+            delattr(site, name)
+        except AttributeError:
+            pass
+    logger.info("Cleared resource viewlet caches.")

Products/CMFPlone/resources/configure.zcml

@@ -3,5 +3,6 @@
     i18n_domain="plone.registry">
 
     <include package=".browser" />
+    <subscriber handler=".eventhandlers.check_registry_update" />
 
 </configure>

Products/CMFPlone/resources/eventhandlers.py

@@ -0,0 +1,16 @@
+from Products.CMFPlone.resources.browser.resource import clear_resource_viewlet_caches
+from Products.GenericSetup.interfaces import IProfileImportedEvent
+from zope.component import adapter
+
+
+@adapter(IProfileImportedEvent)
+def check_registry_update(event):
+    """Check if a profile import may have updated the configuration registry.
+
+    Main concern for now is: the resource registries may have changed.
+    This means the resource viewlet caches should be cleared.
+    See discussion in https://github.com/plone/Products.CMFPlone/issues/3505
+    """
+    if not (event.full_import or "plone.app.registry" in event.steps):
+        return
+    clear_resource_viewlet_caches()

news/3505.bugfix

@@ -0,0 +1,4 @@
+Clear the resource viewlet cache when changing the resource registry or activating an add-on.
+This avoids needing a restart before seeing changes when you run in production mode.
+Fixes [issue 3505](https://github.com/plone/Products.CMFPlone/issues/3505).
+[maurits]