class Roda::RodaPlugins::ContentSecurityPolicy::Policy

def append_formatted_value(s, v)

surrounds them with '
Array :: only accepts 2 element arrays, joins them with - and
Symbol :: Substitutes _ with - and surrounds with '
String :: used verbatim
Handle three types of values when formatting the header: 
def append_formatted_value(s, v)
  case v
  when String
    s << ' ' << v
  when Array
    case v.length
    when 2
      s << " '" << v.join('-') << "'"
    else
      raise RodaError, "unsupported CSP value used: #{v.inspect}"
    end
  when Symbol
    s << " '" << v.to_s.gsub('_', '-') << "'"
  else
    raise RodaError, "unsupported CSP value used: #{v.inspect}"
  end
end