Rails API : Best way to implement authentication?

Question

I\'m writing a Rails 4 app that will expose an API for a mobile app that\'s yet to be developed. Users will authenticate using an e-mail and password from the mobile app.

Answer 1

Another option is to include the module below in your devise MODEL and add the auth_token to you table.

app/models/concerns/token_authenticable.rb

module TokenAuthenticatable
  extend ActiveSupport::Concern

  included do
    before_save :ensure_auth_token
  end

  module ClassMethods
    def find_by_token(token)
      find_by(auth_token: token)
    end
  end

  def ensure_auth_token
    self.auth_token = generate_auth_token if auth_token.blank?
  end

  private

  def generate_auth_token
    loop do
      token = Devise.friendly_token
      break token unless self.class.exists?(auth_token: token)
    end
  end
end

app/controllers/api/v1/login_controller.rb

...
 def login_user(params)
    if params[:authentication]
      @user = User.find_by(auth_token: params[:authentication])
      if @user.nil?
        render json: err('login user by token failed', ERR_USER_NOT_FOUND), status: :not_found
        event('login_user_by_auth_failed', 'token', params[:authentication])
        return
      else
        render status: :ok, json: @user
        return
      end
    else
      user = user.find_by(email: params[:email])
      if user.nil?
        event('login_user_failed_not_found', 'user_email', params[:email])
        render json: err("login user not found #{params[:email]}", ERR_USER_NOT_FOUND), status: :not_found
        return
      end
      if user.access_locked?
        event('login_user_blocked', 'user_id', user.id)
        render json: err("login user account is locked : #{user.id}", ERR_USER_LOCKED), status: :unauthorized
        return
      end
      unless user.try(:valid_password?, params[:password])
        event("login_user_password_does_not_match #{user.id}", 'user_id',  user.id)
        render json: err('login user password does not match', ERR_PASSWORD_NOT_MATCH), status: :unauthorized
        return
      end
      event('login_user_succeeded', 'user_id', user.id)
      @user= user
      if @user.save
        response.headers['authentication'] = @user.auth_token
        render status: :ok, json: @user
        return
      else
        render json: @user.errors, status: :unprocessable_entity
        return
      end
    end
  end
...

Edit: Corrected code-breaking typo