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October 9, 2017 18:15
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C# like object mapper in Ruby
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| class AutoMapper | |
| def initialize(klass, resolvers = {}) | |
| @klass = klass | |
| @resolvers = resolvers | |
| end | |
| def map(object) | |
| klass_instance = @klass.new | |
| fields.each do |attribute| | |
| klass_instance.send("#{attribute}=", value_for(attribute, object)) | |
| end | |
| klass_instance | |
| end | |
| private | |
| def value_for(attribute, object) | |
| value_from_resolver(attribute, object) || value_from_object(attribute, object) | |
| end | |
| def value_from_resolver(attribute, object) | |
| return unless @resolvers[attribute.to_sym].present? | |
| @resolvers[attribute.to_sym].call(object) | |
| end | |
| def value_from_object(attribute, object) | |
| object.public_send(attribute) | |
| rescue NoMethodError => e | |
| nil | |
| end | |
| def fields | |
| active_record_columns || class_attributes | |
| end | |
| def active_record_columns | |
| return unless @klass.ancestors.include?(ActiveRecord::Base) | |
| @klass.column_names | |
| end | |
| def class_attributes | |
| @klass.instance_methods(false) | |
| .select { |method| method.to_s.end_with?('=') } | |
| .map { |method| method.to_s.delete('=') } | |
| end | |
| end |
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