error_handler.rb

require_relative 'constants'

module Rack
  class ErrorHandler
    def initialize(app)
      @app = app
    end

    def log_error(env, error)
      env[RACK_ERRORS].puts(error.full_message)
    end

    def bad_request(error)
      [400, {}, ["Bad Request: #{error.class}"]]
    end

    def internal_server_error(error)
      [500, {}, ["Internal Server Error: #{error.class}"]]
    end

    def call(env)
      @app.call(env)
    rescue BadRequest => error
      log_error(env, error)
      return bad_request(error)
    rescue ScriptError, StandardError => error
      log_error(env, error)
      return internal_server_error(error)
    end
  end
end