# File lib/devise_unix2_chkpwd_authenticatable/strategy.rb, line 13
      def authenticate!
        credentials = params[scope]

        # credentials are empty when using HTTP auth
        if credentials.nil?
          # only HTTP Basic authentication is supported
          request.authorization =~ /^Basic (.*)/m
          usrname, pwd = Base64.decode64($1).split(/:/, 2)
          credentials = {:username => usrname, :password => pwd}
        end

        if resource = mapping.to.authenticate_with_unix2_chkpwd(credentials)
          Rails.logger.info "*** Success!"
          success!(resource)
        else
          Rails.logger.error "*** Invalid!"
          fail(:invalid)
        end
      end