Rails Against The Machine

Ajax login/sign up form:

<% unless logged_in? %>
  <%= error_messages_for :user %>
  
  <div id="login_div">
    <h1>Login or sign up</h1>
    
    <%= error_div_for user %>
        <% remote_form_for :user, :url => {:controller => :account, :action => :signup}, :update => { :success => "login_div", :failure => "login_div" } do |f| -%>
      <p><label for="email">Email</label><br/>
      <%= f.text_field :email %></p>
  
      <p><label for="password">Password</label><br/>
      <%= f.password_field :password %></p>
  
  
      <p><label for="password_confirmation">Confirm Password</label><br/>
      <%= f.password_field :password_confirmation %></p>
  
      <p><%= submit_tag 'Sign up' %></p>
  
  <% end -%>
  </div>

  <%= observe_field(:user_password, :url =>{ :controller => :account, :action => :autofill }, :frequency => 0.5, :with => "'email='+ escape($('user_email').value) + '&password=' + escape($('user_password').value)") %>
<% end %>

When the user types their email and the correct password. They are automatically logged in. This is accomplished by an observe field.

<%= observe_field(:user_password, :url =>{ :controller => :account, :action => :autofill }, :frequency => 0.5, :with => "'email='+ escape($('user_email').value) + '&password=' + escape($('user_password').value)") %>

If they click sign up they are signed up via ajax without whole page refresh using remote form for.

<% remote_form_for :user, :url => {:controller => :account, :action => :signup}, :update => { :success => "login_div", :failure => "login_div" } do |f| -%>

The only issue is validation. This blog shows you how to write a custom rjs.erb file to write validation errors back using the ajax event. But honestly why bother! all you need is to use the :failure callback.

:update => { :success => "login_div", :failure => "login_div" }

Ok now the controller method.

  def signup
    @user = User.new(params[:user])
    return unless request.post?
    @user.save!
    self.current_user = @user
    if request.xml_http_request?
      render :action => 'welcome.html.erb', :layout =>false
    end
    redirect_back_or_default(:controller => '/account', :action => 'index')
    flash[:notice] = "Thanks for signing up!"
  rescue ActiveRecord::RecordInvalid
    if request.xml_http_request?
      render :action => 'signup', :layout =>false
    end
  end

Only thing notable here is the

request.xml_http_request?

method which tells you if the call was a ajax request.

But we can clean this up by defining ajax request as a custom mime type.

  before_filter :adjust_format_for_ajax
  
  def adjust_format_for_ajax  
    request.format = :ajax if request.xml_http_request?
  end

    respond_to do |format|
      format.html do
        flash[:notice] = "Thanks for signing up!"
        redirect_back_or_default(:controller => 'account', :action => 'index')
      end
      format.ajax do
        render :template=>'shared/welcome.html.erb', :layout =>false
        return
      end
    end

Its no shorter but it is neater, especially if you are handling different mime types anyway