kaiwren/wrest

# frozen_string_literal: true

# Copyright 2009 Sidu Ponnappa

# Licensed under the Apache License, Version 2.0 (the "License");
# you may not use this file except in compliance with the License.
# You may obtain a copy of the License at http://www.apache.org/licenses/LICENSE-2.0
# Unless required by applicable law or agreed to in writing, software distributed under the License
# is distributed on an "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
# See the License for the specific language governing permissions and limitations under the License.

module Wrest
  module Components
    module Container
      # An extension to Container that adds support for specifying
      # how the values associated with certain attribute keys
      # should be typecast.
      #
      # This extension can be used in situations where the attributes
      # hash consists of just strings with no associated tup information.
      # For example, params recieved from a web browser may contain
      # attributes like
      #  'id' => '4', 'dateofbirth' => '1984-04-05'
      # and we'd like to have these cast to an integer and a date
      # respectively, rather than have to deal with them as strings.
      module Typecaster
        PARSING = {
          'symbol' => proc { |symbol| symbol.to_s.to_sym },
          'date' => proc { |date| ::Date.parse(date) },
          'datetime' => proc { |time|
            begin
              Time.xmlschema(time).utc
            rescue StandardError
              ::DateTime.parse(time).utc
            end
          },
          'integer' => proc { |integer| integer.to_i },
          'float' => proc { |float| float.to_f },
          'decimal' => proc do |number|
            if number.is_a?(String)
              number.to_d
            else
              BigDecimal(number)
            end
          end,
          'boolean' => proc { |boolean| %w[1 true].include?(boolean.to_s.strip) },
          'string' => proc { |string| string.to_s },
          'yaml' => proc { |yaml|
            begin
              YAML.safe_load(yaml)
            rescue StandardError
              yaml
            end
          },
          'base64Binary' => proc { |bin| ::Base64.decode64(bin) },
          'binary' => proc { |bin, entity| _parse_binary(bin, entity) },
          'file' => proc { |file, entity| _parse_file(file, entity) },
          'double' => proc { |float| float.to_f },
          'dateTime' => proc { |time|
            begin
              Time.xmlschema(time).utc
            rescue StandardError
              ::DateTime.parse(time).utc
            end
          }
        }.freeze

        def self.included(klass)
          # :nodoc:
          klass.extend Typecaster::ClassMethods
          klass.class_eval { include Typecaster::InstanceMethods }
          klass.send(:alias_method, :initialize_without_typecasting, :initialize)
          klass.send(:alias_method, :initialize, :initialize_with_typecasting)
        end

        module Helpers
          def as_base64_binary
            PARSING['base64Binary']
          end

          def as_boolean
            PARSING['boolean']
          end

          def as_decimal
            PARSING['decimal']
          end

          def as_date
            PARSING['date']
          end

          def as_datetime
            PARSING['datetime']
          end

          def as_float
            PARSING['float']
          end

          def as_integer
            PARSING['integer']
          end

          def as_symbol
            PARSING['symbol']
          end

          def as_yaml
            PARSING['yaml']
          end
        end

        module ClassMethods
          # Accepts a set of attribute-name/lambda pairs which are used
          # to typecast string values injected through the constructor.
          # Typically needed when populating an +Container+
          # directly from request params. Typecasting kicks in for
          # a given value _only_ if it is a String, Hash or Array, the
          # three classes that deserilisation can produce.
          #
          # Typecast information is inherited by subclasses; however be
          # aware that explicitly invoking +typecast+ in a subclass will
          # discard inherited typecast information leaving only the casts
          # defined in the subclass.
          #
          # Note that this _will_ increase the time needed to initialize
          # instances.
          #
          # Common typecasts such as integer, float, datetime etc. are
          # available through predefined helpers. See TypecastHelpers
          # for a full list.
          #
          # Example:
          #
          #  class Demon
          #    include Wrest::Components::Container
          #    include Wrest::Components::Container::Typecaster
          #
          #    typecast         :age          =>  as_integer,
          #                     :chi          =>  lambda{|chi| Chi.new(chi)}
          #  end
          #
          #  kai_wren = Demon.new('age' => '1500', 'chi' => '1024')
          #  kai_wren.age           # => 1500
          #  kai_wren.chi           # => #<Chi:0x113af8c @count="1024">
          def typecast(cast_map)
            @typecast_map = @typecast_map ? @typecast_map.merge(cast_map.transform_keys(&:to_sym)) : cast_map.transform_keys(&:to_sym)
          end

          def typecast_map # :nodoc:
            if defined?(@typecast_map)
              @typecast_map
            elsif superclass != Object && superclass.respond_to?(:typecast_map)
              superclass.typecast_map
            else
              {}
            end
          end
        end

        module InstanceMethods # :nodoc:
          def initialize_with_typecasting(attributes = {})
            # :nodoc:
            initialize_without_typecasting(attributes)
            self.class.typecast_map.each do |key, typecaster|
              value = @attributes[key]
              if value.is_a?(String) || value.is_a?(Hash) || value.is_a?(Array)
                @attributes[key] =
                  typecaster.call(value)
              end
            end
          end
        end
      end
    end
  end
end