+ function (field_tag, required)
+ local raw_data = field_tag:get_child_text("value")
+ local data = jid_prep(raw_data);
+ if data and #data > 0 then
+ return data
+ elseif raw_data then
+ return nil, "Invalid JID: " .. raw_data;
+ elseif required then
+ return nil, "Required value missing";
+ end
+ end