This optional parameter allows you to define a Perl function that will be called during packet processing. PreProcessingHook is called for each request before per-Realm user name rewriting, before accounting log files are written, and before any PreAuthHooks. A reference to the current request is passed as the first argument, and a reference to the reply packet currently being constructed is passed as the second argument.

The hook code is compiled by Perl when Radiator starts up. Compilation errors in your hook code will be reported to the log file at start-up time. Runtime errors in your hook will also be reported to the log file when your hook executes. Multiline hooks (i.e. with trailing backslashes (\)) are parsed by Radiator into one long line. Therefore you should not use trailing comments in your hook.

PreProcessingHook can be an arbitrarily complicated Perl function, that might run external processes, consult databases, change the contents of the current request or many other things.

# Fake a new attribute into the request, so its logged in the
# accounting log file
PreProcessingHook sub { ${$_[0]}->add_attr('My-Realm', \
      'some.realm.com');}