expose server version via PROPFIND on root collection and display in the UI for authenticated users

radicale/app/propfind.py

@@ -168,6 +168,8 @@ def xml_propfind_response(
         props = []
         # Should list all properties that can be retrieved by the code below
         props.append(xmlutils.make_clark("D:principal-collection-set"))
+        if user:
+            props.append(xmlutils.make_clark("RADICALE:version"))
         props.append(xmlutils.make_clark("D:current-user-principal"))
         props.append(xmlutils.make_clark("D:current-user-privilege-set"))
         props.append(xmlutils.make_clark("D:supported-report-set"))
@@ -467,6 +469,11 @@ def xml_propfind_response(
                     element.append(child_element)
                 else:
                     is404 = True
+            elif tag == xmlutils.make_clark("RADICALE:version"):
+                if user:
+                    element.text = utils.package_version("radicale")
+                else:
+                    is404 = True
             else:
                 human_tag = xmlutils.make_human_tag(tag)
                 tag_text = collection.get_meta(human_tag)