introduce aux predicate for absolute path type

src/web_api/background.pl

@@ -71,8 +71,9 @@ all_items_external_(_Key-Value,Item) :-
 %
 % Generates the type definition for an item (that is a file or a directory). Type is a valid type as defined by types:check_type_def/1.
 item_type(anyof([DirectoryType,FileType])) :-
+    abs_path_type(AbsPathType),
     CommonKeys=[
-        abs_path: atom('^(/|.*[^/])$'),
+        abs_path: AbsPathType,
         creation_time: integer
     ],
     FileType = dict([

src/web_api/irrelevance.pl

@@ -18,8 +18,9 @@
 % @error api_error(_, implementation_error) if checking the irrelevance itself
 %                                           throws an exception.
 do_handle_irrelevant_file(Parameters,AbsPath) :-
+    abs_path_type(AbsPathType),
     parse_parameters(Parameters, 
-                     dict([abs_path:atom]),
+                     dict([abs_path:AbsPathType]),
                      Parsed),
     AbsPath=Parsed.abs_path,
     catch(user:irrelevant(AbsPath),

src/web_api/requests.pl

@@ -99,3 +99,8 @@ parse_parameters(In, Type, Out) :-
             throw(Exception)
           ) 
     ).
+
+%! abs_path_type(-Type) is det.
+%
+% Return the type definition for an absolute path used to identify items.
+abs_path_type(atom('^(/|.*[^/])$')).