module WEBrick::HTTPAuth::Authenticator

def check_init(config)
  [:UserDB, :Realm].each{|sym|
    unless config[sym]
      raise ArgumentError, "Argument #{sym.inspect} missing."
    end
  }
  @realm     = config[:Realm]
  @userdb    = config[:UserDB]
  @logger    = config[:Logger] || Log::new($stderr)
  @reload_db = config[:AutoReloadUserDB]
  @request_field   = self::class::RequestField
  @response_field  = self::class::ResponseField
  @resp_info_field = self::class::ResponseInfoField
  @auth_exception  = self::class::AuthException
  @auth_scheme     = self::class::AuthScheme
end

def check_scheme(req)
  unless credentials = req[@request_field]
    error("no credentials in the request.")
    return nil
  end
  unless match = /^#{@auth_scheme}\s+/i.match(credentials)
    error("invalid scheme in %s.", credentials)
    info("%s: %s", @request_field, credentials) if $DEBUG
    return nil
  end
  return match.post_match
end

def error(fmt, *args)
  if @logger.error?
    log(:error, fmt, *args)
  end
end

def info(fmt, *args)
  if @logger.info?
    log(:info, fmt, *args)
  end
end

def log(meth, fmt, *args)
  msg = format("%s %s: ", @auth_scheme, @realm)
  msg << fmt % args
  @logger.__send__(meth, msg)
end