Module: Sequel::Plugins::JsonSerializer

Defined in:
lib/sequel/plugins/json_serializer.rb

Overview

The json_serializer plugin handles serializing entire Sequel::Model objects to JSON, as well as support for deserializing JSON directly into Sequel::Model objects. It requires the json library, and can work with either the pure ruby version or the C extension.

Basic Example:

album = Album[1]
album.to_json
# => '{"json_class"=>"Album","id"=>1,"name"=>"RF","artist_id"=>2}'

In addition, you can provide options to control the JSON output:

album.to_json(:only=>:name)
album.to_json(:except=>[:id, :artist_id])
# => '{"json_class"="Album","name"=>"RF"}'

album.to_json(:include=>:artist)
# => '{"json_class":"Album","id":1,"name":"RF","artist_id":2,
       "artist":{"json_class":"Artist","id":2,"name":"YJM"}}'

You can use a hash value with :include to pass options to associations:

album.to_json(:include=>{:artist=>{:only=>:name}})
# => '{"json_class":"Album","id":1,"name":"RF","artist_id":2,
       "artist":{"json_class":"Artist","name":"YJM"}}'

You can specify the :root option to nest the JSON under the name of the model:

album.to_json(:root => true)
# => '{"album":{"id":1,"name":"RF","artist_id":2}}'

In addition to creating JSON, this plugin also enables Sequel::Model objects to be automatically created when JSON is parsed:

json = album.to_json
album = JSON.parse(json)

In addition, you can update existing model objects directly from JSON using from_json:

album.from_json(json)

This works by parsing the JSON (which should return a hash), and then calling set with the returned hash.

Additionally, to_json also exists as a class and dataset method, both of which return all objects in the dataset:

Album.to_json
Album.filter(:artist_id=>1).to_json(:include=>:tags)

Usage:

# Add JSON output capability to all model subclass instances (called before loading subclasses)
Sequel::Model.plugin :json_serializer

# Add JSON output capability to Album class instances
Album.plugin :json_serializer

Defined Under Namespace

Modules: ClassMethods, DatasetMethods, InstanceMethods Classes: Literal

Class Method Summary collapse

Class Method Details

.configure(model, opts = {}) ⇒ Object

Set up the column readers to do deserialization and the column writers to save the value in deserialized_values.



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# File 'lib/sequel/plugins/json_serializer.rb', line 69

def self.configure(model, opts={})
  model.instance_eval do
    @json_serializer_opts = (@json_serializer_opts || {}).merge(opts)
  end
end