ActiveModel Serializers: How do I serialize a resource collection? - ruby-on-rails

Question

I have a bookmarks resource and have mapped it to serve json by default under my api namespace like so in my routes.rb:
namespace :api, defaults: {format: 'json'} do
resources :bookmarks
get ':username', to: 'users#index'
get ':username/bookmarks/:id', to: 'users#show'
end
I have a Api::UsersController controller and a supporting BookmarkSerializer that works just fine on an individual bookmark resource like http://localhost:3000/api/emma_carter/bookmarks/87
But when I try to hit http://localhost:3000/api/emma_carter which is supposed to serve all bookmarks owned by the user, I get all different kinds of errors. Here is my Api::UsersController
module Api
class UsersController < ApplicationController
respond_to :json
def index
user = User.find_by(username: params[:username])
bookmarks = user.bookmarks
render json: bookmarks
end
def show
user = User.find_by(username: params[:username])
bookmark = user.bookmarks.find_by(params[:id])
render json: bookmark
end
end
end
The show method works but the index method gives me ArgumentError in Api::UsersController#index
wrong number of arguments (1 for 0)
UPDATE: Full stack trace here: https://gist.github.com/amite/b79fc42bfd73de5a07bd
screenshot
Here is the serializer:
class BookmarkSerializer < ActiveModel::Serializer
attributes :id, :url, :title, :domain, :notes, :image, :created, :username
belongs_to :user
def created
object.created_at
end
def username
user.username
end
end
Looking at other solutions on stack overflow, I have also tried other versions of my index method:
def index
user = User.find_by(username: params[:username])
bookmarks = user.bookmarks
bookmarks.map { |bookmark| ::BookmarkSerializer.new(bookmark)}.to_json #updated line
end
This gives me the error:
Missing template api/users/index, application/index with {:locale=>[:en], :formats=>[:json], :variants=>[], :handlers=>[:erb, :builder, :raw, :ruby, :coffee, :jbuilder]}.
Next the last version of my index method looks like this:
def index
user = User.find_by(username: params[:username])
bookmarks = user.bookmarks
ActiveModel::ArraySerializer.new(bookmarks, each_serializer: ::BookmarkSerializer).to_json
end
This gives me the error uninitialized constant ActiveModel::ArraySerializer
What am I doing wrong? I am using rails 4.1.5 and the github version of the active_model_serializers
gem.
gem 'active_model_serializers', github: 'rails-api/active_model_serializers'
UPDATE: Since I am trying to output a collection of bookmarks I also tried using a separate serializer
BookmarksSerializer but I am getting the same error: ArgumentError in Api::UsersController#index
wrong number of arguments (1 for 0)
UPDATE2: Here is a version of the index method that kinda works in the sense that it renders the resource collection in json format:
def index
user = User.find_by(username: params[:username])
bookmarks = user.bookmarks
respond_with bookmarks.to_json
end
But this still does not use the BookmarksSerializer
class BookmarksSerializer < ActiveModel::Serializer
attributes :id, :title
end
It just outputs the default hash
Full Gemfile
source 'https://rubygems.org'
# Bundle edge Rails instead: gem 'rails', github: 'rails/rails'
gem 'rails', '4.1.5'
# Use mysql as the database for Active Record
gem 'mysql2'
# Use SCSS for stylesheets
gem 'sass-rails', '~> 4.0.3'
# Use Uglifier as compressor for JavaScript assets
gem 'uglifier', '>= 1.3.0'
# Use CoffeeScript for .js.coffee assets and views
gem 'coffee-rails', '~> 4.0.0'
# See https://github.com/sstephenson/execjs#readme for more supported runtimes
# gem 'therubyracer', platforms: :ruby
gem 'bourbon'
gem 'neat'
gem 'bitters'
gem 'refills'
gem 'wisper'
gem 'rails-ioc'
gem 'reform'
gem 'cells'
gem "pundit"
gem 'active_model_serializers', github: 'rails-api/active_model_serializers'
gem "font-awesome-rails"
gem 'simple_form'
# Use jquery as the JavaScript library
gem 'jquery-rails'
# Build JSON APIs with ease. Read more: https://github.com/rails/jbuilder
gem 'jbuilder', '~> 2.0'
# bundle exec rake doc:rails generates the API under doc/api.
gem 'sdoc', '~> 0.4.0', group: :doc
group :development, :test do
# Call 'debugger' anywhere in the code to stop execution and get a debugger console
gem 'byebug'
gem 'ffaker'
gem 'pry-rails'
gem 'capybara'
gem 'factory_girl_rails'
gem 'database_cleaner'
gem 'capybara-webkit'
gem 'rspec-cells'
# Spring speeds up development by keeping your application running in the background. Read more: https://github.com/rails/spring
gem 'spring'
gem 'spring-commands-rspec'
gem 'rspec-rails'
gem 'guard-rspec'
gem 'rb-fsevent' if `uname` =~ /Darwin/
end
# Use ActiveModel has_secure_password
gem 'bcrypt', '~> 3.1.7'
# Use unicorn as the app server
# gem 'unicorn'
# Use Capistrano for deployment
# gem 'capistrano-rails', group: :development
# Use debugger
# gem 'debugger', group: [:development, :test]

Answer 1

turns out I need to include v0.9 of the gem
gem 'active_model_serializers', github: 'rails-api/active_model_serializers', branch: '0-9-stable'

Answer 2

you could try change:
def index
user = User.find_by(username: params[:username])
bookmarks = user.bookmarks
bookmarks.map { |bookmark| ::BookmarkSerializer.new(bookmark)}.to_json #updated line
end
to:
def index
user = User.find_by(username: params[:username])
bookmarks = user.bookmarks
render json: bookmarks.map { |bookmark| ::BookmarkSerializer.new(bookmark)}
end