Garage

Rails framework to add RESTful hypermedia API to your application.

Gem name has been changed!

We renamed gem name the_garage from version 2.0.0. Please update your Gemfile.

What Is It?

Garage provides a simple, Hypermedia friendly RESTful API to your Rails application using its native RESTful routes. Garage provides a descriptive way to serve your ActiveRecord models, as well as plain old Ruby objects as JSON-based resources.

Garage supports OAuth 2 authorizations via Doorkeeper (more extensions to come), and provides resource-based access controls.

Quickstart

In Gemfile:

# Notice this gem has "the_" prefix for gem name.
gem 'the_garage'

In your Rails model class:

class Employee < ActiveRecord::Base
  include Garage::Representer
  include Garage::Authorizable

  belongs_to :division
  has_many :projects
  property :id
  property :title
  property :first_name
  property :last_name

  property :division, selectable: true
  collection :projects, selectable: true

  link(:division) { division_path(division) }
  link(:projects) { employee_projects_path(self) }

  def self.build_permissions(perms, other, target)
    perms.permits! :read
  end
end

In your controller classes:

class ApplicationController < ActionController::Base
  include Garage::ControllerHelper

  # ...
end

class EmployeesController < ApplicationController
  include Garage::RestfulActions

  def require_resources
    @resources = Employee.all
  end
end

Resources are rendered with respond_with (responders gem). Additional options can be passed to respond_with by implementing respond_with_resources_options (index action) and respond_with_resource_options (show, update destroy actions).

Available options

:paginate - (Boolean) Enable pagination when true. Paginates with the per_page and page params
:per_page - (Integer) value for default number of resources per page when paginating
:max_per_page - (Integer) Maximum resources per page, irrespective of requested per_page
:hard_limit - (Integer) Limit of retrievable records when paginating. Also hides total records.
:distinct_by - (Symbol) Specify a property to count by for total page count
:to_resource_options - (Hash) Options to pass as argument to to_resource(options)

Create decorator for your AR models

With not small application, you may add a presentation layer to build API responses. Define a decorator class with Resource suffix and define #to_resource in your AR model.

class User < ActiveRecord::Base
  def to_resource
    UserResource.new(self)
  end
end

class UserResource
  include Garage::Representer
  include Garage::Authorizable

  property :id
  property :name
  property :email

  delegate :id, :name, :email, to: :@model

  def initialize(model)
    @model = model
  end
end

Advanced Configurations

In config/initializers/garage.rb:

Garage.configure {}

# Optional
Rails.application.config.to_prepare do
  Garage::TokenScope.configure do
    register :public, desc: "accessing publicly available data" do
      access :read, Recipe
    end

    register :read_post, desc: "reading blog post" do
      access :read, Post
    end
  end
end

# If you want to use different authentication/authorization logic.
Garage.configuration.strategy = Garage::Strategy::AuthServer

The following authentication strategies are available.

Garage::Strategy::NoAuthentication - Does not authenticate request and does not verify permission and access on resource operation. For non-public, internal-use Garage application.
Garage::Strategy::Test - Trust request thoroughly, and build access token from request headers. For testing or prototyping.
Garage::Strategy::Doorkeeper - Authenticate request with doorkeeper gem. To use this strategy, bundle garage-doorkeeper gem.
Garage::Strategy::AuthServer - Delegate authentication to OAuth server. This auth strategy has configurations.

Delegate Authentication/Authorization to your OAuth server

To delegate auth to your OAuth server, use Garage::Strategy::AuthServer strategy. Then configure auth server strategy:

Garage.configuration.auth_server_url - A full url of your OAuth server's access token validation endpoint. i.e. https://example.com/token.
Garage.configuration.auth_server_host - A host header value to request to your OAuth server. Can be empty.
Garage.configuration.auth_server_timeout - A read timeout second. Default is 1 second.

The OAuth server must response a json with following structure.

token (string, null) - OAuth access token value.
token_type (string) - OAuth access token value. i.e. bearer type.
scope (string) - OAuth scopes separated by spaces. i.e. public read_user.
application_id (integer) - OAuth application id of the access token.
resource_owner_id (integer, null) - Resource owner id of the access token.
expired_at (string, null) - Expire datetime with string representation.
revoked_at (string, null) - Revoked datetime with string representation.

When requested access token is invalid, OAuth server must response 401.

Customize Authentication/Authorization

Garage supports customizable Authentication/Authorization strategy. The Strategy has some conventions to follow.

Offer OAuth access token via access_token method. With no access token case (does not authenticate request) access_token should return nil.
Register verify_auth hook as before filter in included block if authenticate request. Or register custom authentication hook. The custom authentication hook should response unauthorized using unauthorized_render_options when fails to authenticate a request.
Offer whether verify permission and access in RestfulActions via verify_permission method. Return true to verify them.

module MyStrategy
  extend ActiveSupport::Concern

  included do
    # Register verify_auth hook if you want to authenticate request.
    before_action :verify_auth
  end

  def access_token
    # Fetch some `attributes` from DB or auth server API using request.
    # Then returns an AccessToken with caching.
    @access_token ||= Garage::Strategy::AccessToken.new(attributes)
  end

  # Whether verify permission and access in `RestfulActions`.
  def verify_permission?
    true
  end
end

Distributed tracing

In case you use auth-server strategy, you can setup distributed tracing for the service communication between garage application and auth server. Currently, we support following tracers:

aws-xray using aws-xray gem.
- Bundle aws-xray gem in your application.
- Configure service option for a logical service name of the auth server.

# e.g. aws-xray tracer
require 'aws/xray/hooks/net_http'
Garage::Tracer::AwsXrayTracer.service = 'your-auth-server-name'
Garage.configuration.tracer = Garage::Tracer::AwsXrayTracer