Add a way to check for backend support of version-dependent features …

…via the site service (#1826)

* Add a way to check for backend support of version-dependent features via the site service

* lint & changelog

news/1826.feature

@@ -0,0 +1 @@
+Site service: Indicate whether the site supports filtering URL aliases by date. @davisagli

src/plone/restapi/services/site/get.py

@@ -10,6 +10,7 @@
 from Products.CMFPlone.interfaces import IImagingSchema
 from Products.CMFPlone.interfaces import ISiteSchema
 from Products.CMFPlone.utils import getSiteLogo
+from Products.CMFPlone.controlpanel.browser.redirects import RedirectionSet
 from zope.component import adapter
 from zope.component import getMultiAdapter
 from zope.component import getUtility
@@ -49,6 +50,7 @@ def __call__(self, expand=False):
                 "plone.default_language": language_settings.default_language,
                 "plone.available_languages": language_settings.available_languages,
                 "plone.portal_timezone": self.plone_timezone(),
+                "features": self.features(),
             }
         )
 
@@ -73,6 +75,18 @@ def plone_timezone(self):
 
         return portal_timezone
 
+    def features(self):
+        """Indicates which features are supported by this site.
+
+        This can be used by a client to check for version-dependent features.
+        """
+        result = {
+            "filter_aliases_by_date": hasattr(
+                RedirectionSet, "supports_date_range_filtering"
+            ),
+        }
+        return result
+
 
 class SiteGet(Service):
     def reply(self):

src/plone/restapi/tests/http-examples/site_get.resp

@@ -3,6 +3,9 @@ Content-Type: application/json
 
 {
     "@id": "http://localhost:55001/plone/@site",
+    "features": {
+        "filter_aliases_by_date": false
+    },
     "plone.allowed_sizes": [
         "huge 1600:65536",
         "great 1200:65536",