142 lines
4.6 KiB
Ruby
142 lines
4.6 KiB
Ruby
require 'active_support/core_ext/hash/except'
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require 'active_support/core_ext/hash/slice'
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module ActiveModel
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# == Active Model Serialization
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#
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# Provides a basic serialization to a serializable_hash for your object.
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#
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# A minimal implementation could be:
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#
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# class Person
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# include ActiveModel::Serialization
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#
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# attr_accessor :name
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#
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# def attributes
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# {'name' => nil}
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# end
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# end
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#
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# Which would provide you with:
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#
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# person = Person.new
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# person.serializable_hash # => {"name"=>nil}
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# person.name = "Bob"
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# person.serializable_hash # => {"name"=>"Bob"}
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#
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# You need to declare an attributes hash which contains the attributes
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# you want to serialize. Attributes must be strings, not symbols.
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# When called, serializable hash will use
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# instance methods that match the name of the attributes hash's keys.
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# In order to override this behavior, take a look at the private
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# method +read_attribute_for_serialization+.
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#
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# Most of the time though, you will want to include the JSON or XML
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# serializations. Both of these modules automatically include the
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# <tt>ActiveModel::Serialization</tt> module, so there is no need to explicitly
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# include it.
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#
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# A minimal implementation including XML and JSON would be:
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#
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# class Person
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# include ActiveModel::Serializers::JSON
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# include ActiveModel::Serializers::Xml
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#
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# attr_accessor :name
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#
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# def attributes
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# {'name' => nil}
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# end
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# end
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#
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# Which would provide you with:
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#
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# person = Person.new
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# person.serializable_hash # => {"name"=>nil}
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# person.as_json # => {"name"=>nil}
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# person.to_json # => "{\"name\":null}"
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# person.to_xml # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person...
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#
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# person.name = "Bob"
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# person.serializable_hash # => {"name"=>"Bob"}
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# person.as_json # => {"name"=>"Bob"}
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# person.to_json # => "{\"name\":\"Bob\"}"
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# person.to_xml # => "<?xml version=\"1.0\" encoding=\"UTF-8\"?>\n<serial-person...
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#
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# Valid options are <tt>:only</tt>, <tt>:except</tt>, <tt>:methods</tt> and <tt>:include</tt>.
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# The following are all valid examples:
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#
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# person.serializable_hash(:only => 'name')
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# person.serializable_hash(:include => :address)
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# person.serializable_hash(:include => { :address => { :only => 'city' }})
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module Serialization
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def serializable_hash(options = nil)
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options ||= {}
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attribute_names = attributes.keys
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if only = options[:only]
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attribute_names &= Array(only).map(&:to_s)
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elsif except = options[:except]
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attribute_names -= Array(except).map(&:to_s)
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end
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hash = {}
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attribute_names.each { |n| hash[n] = read_attribute_for_serialization(n) }
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Array(options[:methods]).each { |m| hash[m.to_s] = send(m) if respond_to?(m) }
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serializable_add_includes(options) do |association, records, opts|
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hash[association.to_s] = if records.respond_to?(:to_ary)
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records.to_ary.map { |a| a.serializable_hash(opts) }
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else
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records.serializable_hash(opts)
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end
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end
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hash
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end
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private
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# Hook method defining how an attribute value should be retrieved for
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# serialization. By default this is assumed to be an instance named after
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# the attribute. Override this method in subclasses should you need to
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# retrieve the value for a given attribute differently:
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#
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# class MyClass
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# include ActiveModel::Validations
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#
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# def initialize(data = {})
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# @data = data
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# end
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#
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# def read_attribute_for_serialization(key)
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# @data[key]
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# end
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# end
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#
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alias :read_attribute_for_serialization :send
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# Add associations specified via the <tt>:include</tt> option.
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#
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# Expects a block that takes as arguments:
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# +association+ - name of the association
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# +records+ - the association record(s) to be serialized
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# +opts+ - options for the association records
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def serializable_add_includes(options = {}) #:nodoc:
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return unless includes = options[:include]
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unless includes.is_a?(Hash)
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includes = Hash[Array(includes).map { |n| n.is_a?(Hash) ? n.to_a.first : [n, {}] }]
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end
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includes.each do |association, opts|
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if records = send(association)
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yield association, records, opts
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end
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end
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end
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end
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end
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