pulibrary / orangelight / 0e37073d-109c-440c-949f-49d2aa86311b

module Orangelight

  module Middleware

    class InvalidParameterHandler

      def initialize(app)

        @app = app

      end

      def call(env)

        validate_for!(env)

        @app.call(env)

      rescue ActionController::BadRequest => bad_request_error

        raise bad_request_error if raise_error?(bad_request_error.message)

        Rails.logger.error "Invalid parameters passed in the request: #{bad_request_error} within the environment #{@request.inspect}"

        bad_request_response(env)

      end

      private

        def bad_request_body

          'Bad Request'

        end

        def bad_request_headers(env)

          {

            'Content-Type' => "#{request_content_type(env)}; charset=#{default_charset}",

            'Content-Length' => bad_request_body.bytesize.to_s

          }

        end

        def bad_request_response(env)

          [

            bad_request_status,

            bad_request_headers(env),

            [bad_request_body]

          ]

        end

        def bad_request_status

          400

        end

        def default_charset

          ActionDispatch::Response.default_charset

        end

        def default_content_type

          'text/html'

        end

        def facet_fields_values(params)

          facet_parameter = params.fetch(:f, [])

          raise ActionController::BadRequest, "Invalid facet parameter passed: #{facet_parameter}" unless facet_parameter.is_a?(Array) || facet_parameter.is_a?(Hash)

          facet_parameter.collect do |facet_field, value_list|

            raise ActionController::BadRequest, "Facet field #{facet_field} has a scalar value #{value_list}" if value_list.is_a?(String)

            next unless value_list.nil?

            raise ActionController::BadRequest, "Facet field #{facet_field} has a nil value"

          end

        end

        def check_for_white_spaces(params)

          params.each_key do |k|

            next unless ((k[0].match?(/\s/) || k[-1].match?(/\s/)) && (k.is_a? String)) == true

            raise ActionController::BadRequest, "Param '#{k}' contains a space"

          end

        end

        def raise_error?(_message)

          false

        end

        def request_content_type(env)

          request = request_for(env)

          request.formats.first || default_content_type

        end

        def request_for(env)

          ActionDispatch::Request.new(env.dup)

        end

        def valid_message_patterns

          [

            /invalid %-encoding/,

            /Facet field/,

            /Invalid facet/,

            /contains a space/

          ]

        end

        def validate_for!(env)

          params = request_for(env).params

          check_for_white_spaces(params)

          facet_fields_values(params)

        end

    end

  end

end