json-serializer 
Customizes JSON output through serializer objects.
Installation
Add this line to your application's Gemfile:
gem "json-serializer"And then execute:
$ bundle
Or install it yourself as:
$ gem install json-serializer
Usage
Here's a simple example:
require "json_serializer"
class UserSerializer < JsonSerializer
attribute :id
attribute :first_name
attribute :last_name
endIn this case, we defined a new serializer class and specified the attributes we would like to include in the serialized form.
user = User.create(first_name: "Sonny", last_name: "Moore", admin: true)
UserSerializer.new(user).to_json
# => "{\"id\":1,\"first_name\":\"Sonny\",\"last_name\":\"Moore\"}"You can add a root to the outputted json through the :root option:
user = User.create(first_name: "Sonny", last_name: "Moore", admin: true)
UserSerializer.new(user).to_json(root: :user)
# => "{\"user\":{\"id\":1,\"first_name\":\"Sonny\",\"last_name\":\"Moore\"}}"Arrays
A serializer can be used for objects contained in an array:
require "json_serializer"
class PostSerializer < JsonSerializer
attribute :id
attribute :title
attribute :body
end
posts = []
posts << Post.create(title: "Post 1", body: "Hello!")
posts << Post.create(title: "Post 2", body: "Goodbye!")
PostSerializer.new(posts).to_jsonGiven the example above, it will return a json output like:
[
{ "id": 1, "title": "Post 1", "body": "Hello!" },
{ "id": 2, "title": "Post 2", "body": "Goodbye!" }
]Attributes
By default, before looking up the attribute on the object, it checks the presence of a method with the name of the attribute. This allow serializes to include properties in addition to the object attributes or customize the result of a specified attribute. You can access the object being serialized with the +object+ method.
require "json_serializer"
class UserSerializer < JsonSerializer
attribute :id
attribute :first_name
attribute :last_name
attribute :full_name
def full_name
object.first_name + " " + object.last_name
end
end
user = User.create(first_name: "Sonny", last_name: "Moore")
UserSerializer.new(user).to_json
# => "{\"id\":1,\"first_name\":\"Sonny\",\"last_name\":\"Moore\",\"full_name\":\"Sonny Moore\"}"If you would like direct, low-level control of attribute serialization, you can
completely override to_hash method to return the hash you need:
require "json_serializer"
class UserSerializer < JsonSerializer
attribute :id
attribute :first_name
attribute :last_name
attr_reader :current_user
def initialize(object, current_user)
super(object)
@current_user = current_user
end
def to_hash
hash = super
hash.merge!(admin: object.admin) if current_user.admin?
hash
end
endAttributes with Custom Serializer
You can specify a serializer class for a defined attribute. This is very useful for serializing each element of an association.
require "json_serializer"
class UserSerializer < JsonSerializer
attribute :id
attribute :username
end
class PostSerializer < JsonSerializer
attribute :id
attribute :title
attribute :user, :UserSerializer
attribute :comments, :CommentSerializer
end
class CommentSerializer < JsonSerializer
attribute :id
attribute :content
attribute :user, :UserSerializer
end
admin = User.create(username: "admin", admin: true)
user = User.create(username: "user")
post = Post.create(title: "Hello!", user: admin)
post.comments << Comment.create(content: "First comment", user: user)
PostSerializer.new(post).to_jsonThe example above returns the following json output:
{
"id": 1,
"title": "Hello!",
"user":
{
"id": 1,
"username": "admin"
},
"comments":
[
{
"id": 1,
"content": "First comment",
"user":
{
"id": 2,
"username": "user"
}
}
]
}Contributing
Fork the project with:
$ git clone git@github.com:frodsan/json-serializer.git
To install dependencies, use:
$ bundle install
To run the test suite, do:
$ rake test
For bug reports and pull requests use GitHub.
License
This gem is released under the MIT License.