before_action.rb

before_action.rb

module Sinatra::BeforeAction
  def before_action(&blk)
    before {
      # Find all the routes for the given request method
      routes = self.class.routes[request.request_method]

      # Find the route that matches the pattern/conditions of the
      # request and steal the params.
      routes.select do |pattern, keys, conditions, block|
        process_route(pattern, keys, conditions) { @action_params = params }
        @action_params
      end

      # If there were params stolen, use those to evaluate
      # the block passed into .before_action. Must be sure
      # to set the params back to what they initially were.
      if @action_params
        begin
          original_params = @params
          @params = @action_params
          instance_eval(&blk)
        ensure
          @params = original_params
        end
      end
    }
  end
end