Module: ActiveModel::Serializers::JSON
Relationships & Source Files | |
Extension / Inclusion / Inheritance Descendants | |
Included In:
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Super Chains via Extension / Inclusion / Inheritance | |
Class Chain:
self,
::ActiveSupport::Concern
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Instance Chain:
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Defined in: | activemodel/lib/active_model/serializers/json.rb |
Overview
Active Model JSON Serializer
Class Method Summary
::ActiveSupport::Concern
- Extended
class_methods | Define class methods from given block. |
included | Evaluate given block in context of base class, so that you can write class macros here. |
prepended | Evaluate given block in context of base class, so that you can write class macros here. |
Instance Method Summary
-
#as_json(options = nil)
Returns a hash representing the model.
-
#from_json(json, include_root = include_root_in_json)
Sets the model
attributes
from aJSON
string.
::ActiveModel::Serialization
- Included
#serializable_hash | Returns a serialized hash of your object. |
DSL Calls
included
[ GitHub ]12 13 14 15 16
# File 'activemodel/lib/active_model/serializers/json.rb', line 12
included do extend ActiveModel::Naming class_attribute :include_root_in_json, instance_writer: false, default: false end
Instance Method Details
#as_json(options = nil)
Returns a hash representing the model. Some configuration can be passed through options
.
The option include_root_in_json
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 include_root_in_json
option is false
.
user = User.find(1)
user.as_json
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006-08-01T17:27:133.000Z", "awesome" => true}
ActiveRecord::Base.include_root_in_json = true
user.as_json
# => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006-08-01T17:27:13.000Z", "awesome" => true } }
This behavior can also be achieved by setting the :root
option to true
as in:
user = User.find(1)
user.as_json(root: true)
# => { "user" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006-08-01T17:27:13.000Z", "awesome" => true } }
If you prefer, :root
may also be set to a custom string key instead as in:
user = User.find(1)
user.as_json(root: "author")
# => { "author" => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006-08-01T17:27:13.000Z", "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" => "2006-08-01T17:27:13.000Z", "awesome" => true}
The :only
and :except
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 :methods
:
user.as_json(methods: :permalink)
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006-08-01T17:27:13.000Z", "awesome" => true,
# "permalink" => "1-konata-izumi" }
To include associations use :include
:
user.as_json(include: :posts)
# => { "id" => 1, "name" => "Konata Izumi", "age" => 16,
# "created_at" => "2006-08-01T17:27:13.000Z", "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" => "2006-08-01T17:27:13.000Z", "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" } ] }
#from_json(json, include_root = include_root_in_json)
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|
send("#{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, true) # => #<Person:0x007fec5e7a0088 @age=22, @awesome=true, @name="bob">
person.name # => "bob"
person.age # => 22
person.awesome # => true
# File 'activemodel/lib/active_model/serializers/json.rb', line 146
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