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rails--rails/activemodel/lib/active_model/serializers/json.rb
2012-10-26 21:46:15 -05:00

145 lines
5.5 KiB
Ruby

require 'active_support/json'
module ActiveModel
module Serializers
# == Active Model JSON Serializer
module JSON
extend ActiveSupport::Concern
include ActiveModel::Serialization
included do
extend ActiveModel::Naming
class_attribute :include_root_in_json
self.include_root_in_json = false
end
# Returns a hash representing the model. Some configuration can be
# passed through +options+.
#
# The option <tt>include_root_in_json</tt> controls the top-level behavior
# of +as_json+. If +true+, +as_json+ will emit a single root node named
# after the object's type. The default value for <tt>include_root_in_json</tt>
# option is +false+.
#
# user = User.find(1)
# user.as_json
# # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# # "created_at" => "2006/08/01", "awesome" => true}
#
# ActiveRecord::Base.include_root_in_json = true
#
# user.as_json
# # => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# # "created_at" => "2006/08/01", "awesome" => true } }
#
# This behavior can also be achieved by setting the <tt>:root</tt> option
# to +true+ as in:
#
# user = User.find(1)
# user.as_json(root: true)
# # => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# # "created_at" => "2006/08/01", "awesome" => true } }
#
# Without any +options+, the returned Hash will include all the model's
# attributes.
#
# user = User.find(1)
# user.as_json
# # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# # "created_at" => "2006/08/01", "awesome" => true}
#
# The <tt>:only</tt> and <tt>:except</tt> options can be used to limit
# the attributes included, and work similar to the +attributes+ method.
#
# user.as_json(only: [:id, :name])
# # => { "id" => 1, "name" => "Konata Izumi" }
#
# user.as_json(except: [:id, :created_at, :age])
# # => { "name" => "Konata Izumi", "awesome" => true }
#
# To include the result of some method calls on the model use <tt>:methods</tt>:
#
# user.as_json(methods: :permalink)
# # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# # "created_at" => "2006/08/01", "awesome" => true,
# # "permalink" => "1-konata-izumi" }
#
# To include associations use <tt>:include</tt>:
#
# user.as_json(include: :posts)
# # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# # "created_at" => "2006/08/01", "awesome" => true,
# # "posts" => [ { "id" => 1, "author_id" => 1, "title" => "Welcome to the weblog" },
# # { "id" => 2, "author_id" => 1, "title" => "So I was thinking" } ] }
#
# Second level and higher order associations work as well:
#
# user.as_json(include: { posts: {
# include: { comments: {
# only: :body } },
# only: :title } })
# # => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# # "created_at" => "2006/08/01", "awesome" => true,
# # "posts" => [ { "comments" => [ { "body" => "1st post!" }, { "body" => "Second!" } ],
# # "title" => "Welcome to the weblog" },
# # { "comments" => [ { "body" => "Don't think too hard" } ],
# # "title" => "So I was thinking" } ] }
def as_json(options = nil)
root = if options && options.key?(:root)
options[:root]
else
include_root_in_json
end
if root
root = self.class.model_name.element if root == true
{ root => serializable_hash(options) }
else
serializable_hash(options)
end
end
# Sets the model +attributes+ from a JSON string. Returns +self+.
#
# class Person
# include ActiveModel::Serializers::JSON
#
# attr_accessor :name, :age, :awesome
#
# def attributes=(hash)
# hash.each do |key, value|
# instance_variable_set("@#{key}", value)
# end
# end
#
# def attributes
# instance_values
# end
# end
#
# json = { name: 'bob', age: 22, awesome:true }.to_json
# person = Person.new
# person.from_json(json) # => #<Person:0x007fec5e7a0088 @age=22, @awesome=true, @name="bob">
# person.name # => "bob"
# person.age # => 22
# person.awesome # => true
#
# The default value for +include_root+ is +false+. You can change it to
# +true+ if the given JSON string includes a single root node.
#
# json = { person: { name: 'bob', age: 22, awesome:true } }.to_json
# person = Person.new
# person.from_json(json) # => #<Person:0x007fec5e7a0088 @age=22, @awesome=true, @name="bob">
# person.name # => "bob"
# person.age # => 22
# person.awesome # => true
def from_json(json, include_root=include_root_in_json)
hash = ActiveSupport::JSON.decode(json)
hash = hash.values.first if include_root
self.attributes = hash
self
end
end
end
end