JSONAPI::Utils

Simple yet powerful way to have your Rails API compliant with JSON API.

JSONAPI::Utils (JU) was built on top of JSONAPI::Resources taking advantage of its resource-driven style and bringing a Rails way to build modern APIs with no or less learning curve.

Installation

Add these lines to your application's Gemfile:

gem 'jsonapi-utils', '~> 0.4.4'

And then execute:

$ bundle

Response Macros

jsonapi_render

Takes ActiveRecord/Hash objects and generates JSON API-compliant responses.

# GET /users
def index
  jsonapi_render json: User.all
end

# GET /users/:id
def show
  jsonapi_render json: User.find(params[:id])
end

Arguments:

• json: ActiveRecord or Hash object to be rendered as JSON document;
• status: HTTP status code (Integer or Symbol). If ommited a status code will be automatically infered;
• options:
  • resource: explicitly points the resource to be used in the serialization. By default, JU will select resources by inferencing from controller's name.
  • count: explicitly points the total count of records for the request in order to build a proper pagination. By default, JU will count the total number of records.
  • model: sets the model reference in cases when json is a Hash or a collection of Hashes.

Examples:

# Specify a particular HTTP status code
jsonapi_render json: new_user, status: :created

# Forcing a different resource
jsonapi_render json: User.all, options: { resource: V2::UserResource }

# Using a specific count
jsonapi_render json: User.some_weird_scope, options: { count: User.some_weird_scope_count }

# Hash rendering
jsonapi_render json: { data: { id: 1, first_name: 'Tiago' } }, options: { model: User }

# Collection of Hashes rendering
jsonapi_render json: { data: [{ id: 1, first_name: 'Tiago' }, { id: 2, first_name: 'Doug' }] }, options: { model: User }

jsonapi_format

In the backstage this is the method that actually parses ActiveRecord/Hash objects and builds a new Hash compliant with JSON API. It can be called anywhere in your controllers being very useful whenever you need to work with a JSON API "serialized" version of your object before rendering it.

Note: because of semantic reasons JSONAPI::Utils#jsonapi_serialize was renamed being now just an alias to JSONAPI::Utils#jsonapi_format.

def index
  result = do_some_magic(jsonapi_format(User.all))
  render json: result
end

Arguments:

• It receives the same options as jsonapi_render.

Usage

Let's say we have a Rails app for a super simple blog.

Models

# app/models/user.rb
class User < ActiveRecord::Base
  has_many :posts
  validates :first_name, :last_name, presence: true
end

# app/models/user.rb
class Post < ActiveRecord::Base
  belongs_to :author, class_name: 'User', foreign_key: 'user_id'
  validates :title, :body, presence: true
end

Resources

Here is where we define how the serialization will behave:

# app/resources/user_resource.rb
class UserResource < JSONAPI::Resource
  attributes :first_name, :last_name, :full_name, :birthday
  attribute :full_name

  has_many :posts

  def full_name
    "#{@model.first_name} #{@model.last_name}"
  end
end

# app/resources/post_resource.rb
class PostResource < JSONAPI::Resource
  attributes :title, :body
  has_one :author
end

Routes & Controllers

Let's define our routes using the jsonapi_resources and jsonapi_links macros provied by the jsonapi-resources gem:

Rails.application.routes.draw do
  jsonapi_resources :users do
    jsonapi_resources :posts
    jsonapi_links :posts
  end
end

And a base controller to include the features from jsonapi-resources and jsonapi-utils:

# app/controllers/base_controller.rb
class BaseController < JSONAPI::ResourceController
  include JSONAPI::Utils
  protect_from_forgery with: :null_session
  rescue_from ActiveRecord::RecordNotFound, with: :jsonapi_render_not_found
end

For this example, let's get focused only on read actions. After including JSONAPI::Utils we can use the jsonapi_render method in order to generate responses which follow the JSON API's standards.

# app/controllers/users_controller.rb
class UsersController < BaseController
  before_action :load_user, only: [:show]

  # GET /users
  def index
    jsonapi_render json: User.all
  end

  # GET /users/:id
  def show
    jsonapi_render json: @user
  end

  private

  def load_user
    @user = User.find(params[:id])
  end
end

And:

# app/controllers/posts_controller.rb
class PostsController < BaseController
  before_action :load_user, only: [:index, :show]
  before_action :load_post, only: [:show]

  # GET /users/:user_id/posts
  def index
    posts = @user.posts.enabled
    jsonapi_render json: posts, options: { count: posts.count }
  end

  # GET /users/:user_id/posts/:id
  def show
    jsonapi_render json: @post
  end

  private

  def load_user
    @user = User.find(params[:user_id])
  end

  def load_post
    @post = @user.posts.find(params[:id])
  end
end

Errors

Not found

As you might have seen in BaseController this line will handle all errors related to not found resources:

rescue_from ActiveRecord::RecordNotFound, with: :jsonapi_render_not_found

The jsonapi_render_not_found method will produce the following error payload:

HTTP/1.1 404 Not found
Content-Type: application/vnd.api+json

{
  "errors": [
    {
      "title": "Record not found",
      "detail": "The record identified by 3 could not be found.",
      "code": "404",
      "status": "404"
    }
  ]
}

In case you prefer rendering not found resources with null data and 200 OK status code, you can use jsonapi_render_not_found_with_null to produce:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "data": null
}

If you need to create custom error message, check this.

Initializer

In order to enable a proper pagination, record count etc, let's define an initializer such as:

# config/initializers/jsonapi_resources.rb
JSONAPI.configure do |config|
  config.json_key_format = :underscored_key
  config.route_format = :dasherized_route

  config.operations_processor = :active_record

  config.allow_include = true
  config.allow_sort = true
  config.allow_filter = true

  config.raise_if_parameters_not_allowed = true

  config.default_paginator = :paged

  config.top_level_links_include_pagination = true

  config.default_page_size = 10
  config.maximum_page_size = 20

  config.top_level_meta_include_record_count = true
  config.top_level_meta_record_count_key = :record_count

  config.use_text_errors = false

  config.exception_class_whitelist = []

  config.always_include_to_one_linkage_data = false
end

You may want a different configuration for your API. For more information check this.

Requests & Responses

Here's some examples of requests – based on those sample controllers – and their respective JSON responses.

• Collection
• Collection (options)
• Single record
• Record (options)
• Relationships (identifier objects)
• Nested resources

Collection

Request:

GET /users HTTP/1.1
Accept: application/vnd.api+json

Response:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "data": [
    {
      "id": "1",
      "type": "users",
      "links": {
        "self": "http://api.myblog.com/users/1"
      },
      "attributes": {
        "first_name": "Tiago",
        "last_name": "Guedes",
        "full_name": "Tiago Guedes",
        "birthday": null
      },
      "relationships": {
        "posts": {
          "links": {
            "self": "http://api.myblog.com/users/1/relationships/posts",
            "related": "http://api.myblog.com/users/1/posts"
          }
        }
      }
    },
    {
      "id": "2",
      "type": "users",
      "links": {
        "self": "http://api.myblog.com/users/2"
      },
      "attributes": {
        "first_name": "Douglas",
        "last_name": "André",
        "full_name": "Douglas André",
        "birthday": null
      },
      "relationships": {
        "posts": {
          "links": {
            "self": "http://api.myblog.com/users/2/relationships/posts",
            "related": "http://api.myblog.com/users/2/posts"
          }
        }
      }
    }
  ],
  "meta": {
    "record_count": 2
  },
  "links": {
    "first": "http://api.myblog.com/users?page%5Bnumber%5D=1&page%5Bsize%5D=10",
    "last": "http://api.myblog.com/users?page%5Bnumber%5D=1&page%5Bsize%5D=10"
  }
}

Collection (options)

Request:

GET /users?include=posts&fields[users]=first_name,last_name,posts&fields[posts]=title&sort=first_name,last_name&page[number]=1&page[size]=1 HTTP/1.1
Accept: application/vnd.api+json

Response:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "data": [
    {
      "id": "2",
      "type": "users",
      "links": {
        "self": "http://api.myblog.com/users/2"
      },
      "attributes": {
        "first_name": "Douglas",
        "last_name": "André"
      },
      "relationships": {
        "posts": {
          "links": {
            "self": "http://api.myblog.com/users/2/relationships/posts",
            "related": "http://api.myblog.com/users/2/posts"
          },
          "data": []
        }
      }
    },
    {
      "id": "1",
      "type": "users",
      "links": {
        "self": "http://api.myblog.com/users/1"
      },
      "attributes": {
        "first_name": "Tiago",
        "last_name": "Guedes"
      },
      "relationships": {
        "posts": {
          "links": {
            "self": "http://api.myblog.com/users/1/relationships/posts",
            "related": "http://api.myblog.com/users/1/posts"
          },
          "data": [
            {
              "type": "posts",
              "id": "1"
            }
          ]
        }
      }
    }
  ],
  "included": [
    {
      "id": "1",
      "type": "posts",
      "links": {
        "self": "http://api.myblog.com/posts/1"
      },
      "attributes": {
        "title": "An awesome post"
      }
    }
  ],
  "meta": {
    "record_count": 2
  },
  "links": {
    "first": "http://api.myblog.com/users?fields%5Bposts%5D=title&fields%5Busers%5D=first_name%2Clast_name%2Cposts&include=posts&page%5Blimit%5D=2&page%5Boffset%5D=0&sort=first_name%2Clast_name",
    "last": "http://api.myblog.com/users?fields%5Bposts%5D=title&fields%5Busers%5D=first_name%2Clast_name%2Cposts&include=posts&page%5Blimit%5D=2&page%5Boffset%5D=0&sort=first_name%2Clast_name"
  }
}

Single record

Request:

GET /users/1 HTTP/1.1
Accept: application/vnd.api+json

Response:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "data": {
    "id": "1",
    "type": "users",
    "links": {
      "self": "http://api.myblog.com/users/1"
    },
    "attributes": {
      "first_name": "Tiago",
      "last_name": "Guedes",
      "full_name": "Tiago Guedes",
      "birthday": null
    },
    "relationships": {
      "posts": {
        "links": {
          "self": "http://api.myblog.com/users/1/relationships/posts",
          "related": "http://api.myblog.com/users/1/posts"
        }
      }
    }
  }
}

Single record (options)

Request:

GET /users/1?include=posts&fields[users]=full_name,posts&fields[posts]=title HTTP/1.1
Accept: application/vnd.api+json

Response:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "data": {
    "id": "1",
    "type": "users",
    "links": {
      "self": "http://api.myblog.com/users/1"
    },
    "attributes": {
      "full_name": "Tiago Guedes"
    },
    "relationships": {
      "posts": {
        "links": {
          "self": "http://api.myblog.com/users/1/relationships/posts",
          "related": "http://api.myblog.com/users/1/posts"
        },
        "data": [
          {
            "type": "posts",
            "id": "1"
          }
        ]
      }
    }
  },
  "included": [
    {
      "id": "1",
      "type": "posts",
      "links": {
        "self": "http://api.myblog.com/posts/1"
      },
      "attributes": {
        "title": "An awesome post"
      }
    }
  ]
}

Relationships (identifier objects)

Request:

GET /users/1/relationships/posts HTTP/1.1
Accept: application/vnd.api+json

Response:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "links": {
    "self": "http://api.myblog.com/users/1/relationships/posts",
    "related": "http://api.myblog.com/users/1/posts"
  },
  "data": [
    {
      "type": "posts",
      "id": "1"
    }
  ]
}

Nested resources

Request:

GET /users/1/posts HTTP/1.1
Accept: application/vnd.api+json

Response:

HTTP/1.1 200 OK
Content-Type: application/vnd.api+json

{
  "data": [
    {
      "id": "1",
      "type": "posts",
      "links": {
        "self": "http://api.myblog.com/posts/1"
      },
      "attributes": {
        "title": "An awesome post",
        "body": "Lorem ipsum dolot sit amet"
      },
      "relationships": {
        "author": {
          "links": {
            "self": "http://api.myblog.com/posts/1/relationships/author",
            "related": "http://api.myblog.com/posts/1/author"
          }
        }
      }
    }
  ],
  "meta": {
    "record_count": 1
  },
  "links": {
    "first": "http://api.myblog.com/posts?page%5Bnumber%5D=1&page%5Bsize%5D=10",
    "last": "http://api.myblog.com/posts?page%5Bnumber%5D=1&page%5Bsize%5D=10"
  }
}

Development

After checking out the repo, run bin/setup to install dependencies. Then, run rake rspec to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

To install this gem onto your local machine, run bundle exec rake install. To release a new version, update the version number in version.rb, and then run bundle exec rake release, which will create a git tag for the version, push git commits and tags, and push the .gem file to rubygems.org.

Contributing

Bug reports and pull requests are welcome on GitHub at https://github.com/[USERNAME]/jsonapi-utils. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

License

The gem is available as open source under the terms of the MIT License.