Alan DeKok via Freeradius-Users <freeradius-users@lists.freeradius.org> wrote:
On Apr 13, 2026, at 4:59 PM, g4-lisz@tonarchiv.ch wrote:
I read about the default / alternation syntax for string expansion, like %{%{Foo}:-bar}.
But what I needed is this: if (foo != '' ) ? '[ %{foo} ]' : 'null'.
This is for a JSON request string in a REST module configuration. The request property in question must be a JSON array ( [ .. ] ) or 'null'.
I could use Unlang IF and declare the complete JSON request in different versions depending on foo. But I would prefer to do this with expansion inside the JSON string definition, if possible.
You'll have to use 'if'. There is a mods-available/json, and you can do:
%{json_encode:&foo}
Except that if "foo" doesn't exist, it returns an empty json object: "{}"
You could use another attribute and assign the json text to that attribute using if/else, then base the REST stuff off that attribute. That at least keeps your REST query DRY. There are some temporary internal-use-only attributes in the dictionary for stuff like this. If you are running a version that has mod_json you should use it. Performing data sanitation by hand is cringy.