Anonymous users with Devise?

If I want to build a chatroom with rails (ca开发者_开发百科nonical case) with a choice of anonymous ('pick a nickname') and authorized (u/n & pw), how would I build this with Devise?

I've successfully got Devise working in the latter case, it's the anonymous part (create & maintain a session) I'm struggling with.

---

There is actually a Devise Wiki page for that, only they call it Guest user:

How To: Create a guest user

---

use extra before_filter to setup anonymous user, for instance,

def anonymous_sign_in
  return if user_signed_in?
  u = User.new(:type => 'anonymous')
  u.save(:validate => false)
  sign_in :user, u
end

---

Another option is not to sign in a guest user, but have current_user return a guest user in the absence of a signed in user.

In the below if the user is not signed in then current_user will return a guest user. So any controller which can be access without signing in do not need the authenticate_user! before filter.

def current_user                                                              
  super || guest_user                                                         
end                                                                           

def guest_user                                                                
  User.find(session[:guest_user_id].nil? ? session[:guest_user_id] = create_guest_user.id : session[:guest_user_id])
end                                                                           

def create_guest_user                                                         
  token = SecureRandom.base64(15)                                             
  user = User.new(:first_name => "anonymous", :last_name => 'user', :password => token, :email => "#{token@example.com}")
  user.save(:validate => false)                                               
  user                                                                        
end   

---

#user.rb
    # Creates an anonymous user. An anonymous user is basically an auto-generated
    # +User+ account that is created for the customer behind the scenes and its
    # completely transparently to the customer.
    def anonymous!(nickname)
      temp_token = SecureRandom.base64(15).tr('+/=', 'xyz')
      usr = ::User.new(email: "#{temp_token}@example.net", password: temp_token, password_confirmation: temp_token, nickname: nickname)
      usr.save!(validate: false)
      usr
    end

You can then delete the record when it suits.

---

This is how I did it in Rails 6:

class ApplicationController < ActionController::Base
  before_action :anonymous_sign_in

  def anonymous_sign_in
    return if user_signed_in?

    u = User.new(:name => 'anonymous')
    u.save(:validate => false)
    sign_in :user, u
  end
end

From the default devise generated model, I've removed the email default and null constraint, and added the name:

class DeviseCreateUsers < ActiveRecord::Migration[6.0]
  def change
    create_table :users do |t|
      t.string :email
      t.string :name

      ## Database authenticatable
      # t.string :email,              null: false, default: ""
      t.string :encrypted_password, null: false, default: ""

      # ...