RESTful login with devise (Rails 4)

Question

How do I do RESTful sign-up and sign-in using devise in Ruby on Rails (I am using version 4)?

I could not find any documentation with regards to the parameters (e.g. email, password) that I should POST to the server.

It seems that RESTful login using JSON data (e.g. via AJAX) is not supported out of the box in the current version of devise - the default behavior is to send back a whole HTML page for any type of request made, instead of a JSON object for handling JSON request specifically.

Does this mean that I need to create/extend custom controller for handling user registration and login for RESTful apps using JSON? If so, please elaborate.

Answer 1

If you're using Devise, all of the RESTful actions have been provided through their forms & controller (if you browse to http://your-app.com/users/sign_up, you'll be able to register etc)

If you're looking to make your Devise handle JSON, you are correct in that it's not handled "out of the box", but fortunately, there is a way to do it:

Live Code

#config/routes (notice custom controllers)
devise_for :users, :path => '', :controllers => {:sessions => 'sessions', :registrations => 'registrations'}

#app/controllers/registrations_controller.rb
class RegistrationsController < DeviseController
  prepend_before_filter :require_no_authentication, :only => [ :new, :create, :cancel ]
  prepend_before_filter :authenticate_scope!, :only => [:edit, :update, :destroy]

  before_filter :configure_permitted_parameters

  prepend_view_path 'app/views/devise'

  # GET /resource/sign_up
  def new
    build_resource({})
    respond_with self.resource
  end

  # POST /resource
  def create
    build_resource(sign_up_params)

    if resource.save
      if resource.active_for_authentication?
        set_flash_message :notice, :signed_up if is_navigational_format?
        sign_up(resource_name, resource)
        respond_with resource, :location => after_sign_up_path_for(resource)
      else
        set_flash_message :notice, :"signed_up_but_#{resource.inactive_message}" if is_navigational_format?
        expire_session_data_after_sign_in!
        respond_with resource, :location => after_inactive_sign_up_path_for(resource)
      end
    else
      clean_up_passwords resource

      respond_to do |format|
        format.json { render :json => resource.errors, :status => :unprocessable_entity }
        format.html { respond_with resource }
      end
    end
  end

  # GET /resource/edit
  def edit
    render :edit
  end

  # PUT /resource
  # We need to use a copy of the resource because we don't want to change
  # the current user in place.
  def update
    self.resource = resource_class.to_adapter.get!(send(:"current_#{resource_name}").to_key)
    prev_unconfirmed_email = resource.unconfirmed_email if resource.respond_to?(:unconfirmed_email)

    if update_resource(resource, account_update_params)
      if is_navigational_format?
        flash_key = update_needs_confirmation?(resource, prev_unconfirmed_email) ?
          :update_needs_confirmation : :updated
        set_flash_message :notice, flash_key
      end
      sign_in resource_name, resource, :bypass => true
      respond_with resource, :location => after_update_path_for(resource)
    else
      clean_up_passwords resource
      respond_with resource
    end
  end

  # DELETE /resource
  def destroy
    resource.destroy
    Devise.sign_out_all_scopes ? sign_out : sign_out(resource_name)
    set_flash_message :notice, :destroyed if is_navigational_format?
    respond_with_navigational(resource){ redirect_to after_sign_out_path_for(resource_name) }
  end

  # GET /resource/cancel
  # Forces the session data which is usually expired after sign
  # in to be expired now. This is useful if the user wants to
  # cancel oauth signing in/up in the middle of the process,
  # removing all OAuth session data.
  def cancel
    expire_session_data_after_sign_in!
    redirect_to new_registration_path(resource_name)
  end

  protected

  # Custom Fields
  def configure_permitted_parameters
    devise_parameter_sanitizer.for(:sign_up) do |u|
      u.permit(:first_name, :last_name,
        :email, :password, :password_confirmation)
    end
  end

  def update_needs_confirmation?(resource, previous)
    resource.respond_to?(:pending_reconfirmation?) &&
      resource.pending_reconfirmation? &&
      previous != resource.unconfirmed_email
  end

  # By default we want to require a password checks on update.
  # You can overwrite this method in your own RegistrationsController.
  def update_resource(resource, params)
    resource.update_with_password(params)
  end

  # Build a devise resource passing in the session. Useful to move
  # temporary session data to the newly created user.
  def build_resource(hash=nil)
    self.resource = resource_class.new_with_session(hash || {}, session)
  end

  # Signs in a user on sign up. You can overwrite this method in your own
  # RegistrationsController.
  def sign_up(resource_name, resource)
    sign_in(resource_name, resource)
  end

  # The path used after sign up. You need to overwrite this method
  # in your own RegistrationsController.
  def after_sign_up_path_for(resource)
    after_sign_in_path_for(resource)
  end

  # The path used after sign up for inactive accounts. You need to overwrite
  # this method in your own RegistrationsController.
  def after_inactive_sign_up_path_for(resource)
    respond_to?(:root_path) ? root_path : "/"
  end

  # The default url to be used after updating a resource. You need to overwrite
  # this method in your own RegistrationsController.
  def after_update_path_for(resource)
    signed_in_root_path(resource)
  end

  # Authenticates the current scope and gets the current resource from the session.
  def authenticate_scope!
    send(:"authenticate_#{resource_name}!", :force => true)
    self.resource = send(:"current_#{resource_name}")
  end

  def sign_up_params
    devise_parameter_sanitizer.sanitize(:sign_up)
  end

  def account_update_params
    devise_parameter_sanitizer.sanitize(:account_update)
  end
end

This is probably excessive, but it works (try registering or logging in at http://firststop.herokuapp.com). You could probably achieve the same thing with this code (completely untested):

def create #-> completely untested & speculative
    super do |format|
        format.json { render :json => resource.errors, :status => :unprocessable_entity }
        format.html { respond_with resource }
    end
end

Login Code

class SessionsController < DeviseController
  prepend_before_filter :require_no_authentication, :only => [ :new, :create ]
  prepend_before_filter :allow_params_authentication!, :only => :create
  prepend_before_filter { request.env["devise.skip_timeout"] = true }

  prepend_view_path 'app/views/devise'

  # GET /resource/sign_in
  def new
    self.resource = resource_class.new(sign_in_params)
    clean_up_passwords(resource)
    respond_with(resource, serialize_options(resource))
  end

  # POST /resource/sign_in
  def create
    self.resource = warden.authenticate!(auth_options)
    set_flash_message(:notice, :signed_in) if is_navigational_format?
    sign_in(resource_name, resource)

        respond_to do |format|
                format.json { render :json => {}, :status => :ok }
                format.html { respond_with resource, :location => after_sign_in_path_for(resource) } 
        end
  end

  # DELETE /resource/sign_out
  def destroy
    redirect_path = after_sign_out_path_for(resource_name)
    signed_out = (Devise.sign_out_all_scopes ? sign_out : sign_out(resource_name))
    set_flash_message :notice, :signed_out if signed_out && is_navigational_format?

    # We actually need to hardcode this as Rails default responder doesn't
    # support returning empty response on GET request
    respond_to do |format|
      format.all { head :no_content }
      format.any(*navigational_formats) { redirect_to redirect_path }
    end
  end


  protected

  def sign_in_params
    devise_parameter_sanitizer.sanitize(:sign_in)
  end

  def serialize_options(resource)
    methods = resource_class.authentication_keys.dup
    methods = methods.keys if methods.is_a?(Hash)
    methods << :password if resource.respond_to?(:password)
    { :methods => methods, :only => [:password] }
  end

  def auth_options
    { :scope => resource_name, :recall => "#{controller_path}#new" }
  end
end