Password less activation

Note: This will not work if you also using external authentication (OAuth).

I recommend following almost all the steps on the User Activation example. But then modify things slightly as follows.

Fix the user model so that the activation emails will be sent even without password at the creation.

class User < ActiveRecord::Base
  authenticates_with_sorcery!

  # change the validations
  validates :password, :presence => true, :confirmation => true, :on => :update
  validates :first_name, :presence => true, :on => :update
  validates :last_name,  :presence => true, :on => :update

 # fix sorcery so that we can activate without a password
  before_create :setup_activation
  
  def external?
    false
  end

end

Add a route for the confirmation to take place.

# config/routes.rb
resources :users do
  member do
    get :activate
    put :confirm
  end
end

Add a confirmation action, and modify the activation action.
You should have @user.activate! within activate, we gonna move that line to confirm so the account is only activated if the informations are given.

# app/controllers/users_controller.rb
skip_before_filter :require_login, :only => [:index, :new, :create, :activate, :confirm]

def activate
  if (@user = User.load_from_activation_token(params[:id]))
    # no action needed here
  else
    not_authenticated
  end
end

def confirm
  @user = User.find params[:id]
  if @user.update_attributes(params[:user])
    @user.activate!
    redirect_to login_url, :notice => 'Your account is now activated.'
  else
    render :activate
  end
end

Here I redirect the user to the login page, but you can let the app handle that part:

def confirm
  @user = User.find params[:id]
  if @user.update_attributes(params[:user])
    @user.activate!
    auto_login @user
    redirect_to @user, notice: 'Your account is now activated.'
  else
    render :activate
  end
end

Now just add the activation form (I use formtastic, but the standard form builder works fine).

# app/view/users/activate.html.haml
%h1 Activate

= semantic_form_for @user, :url => confirm_user_path(@user) do |f|
  = f.inputs do
    = f.input :first_name
    = f.input :last_name
    = f.input :password
    = f.input :password_confirmation
  = f.actions :submit