Noupe Editorial Team July 16th, 2009

A Simple Twitter App with Ruby on Rails – User Authentication

This article is the second part in a three part series. In the first part we created some basic functionality to allow the user to post messages in a similar way to Twitter. If you have not completed the first part of this tutorial, please do so now.

In this instalment, we will learn how to add some basic user authentication using a useful plugin called nifty_generators. So lets get started!

Get the Gem!

nifty_generators Gem

The nifty_generators gem was created by Ryan Bates, better known for his great RailsCast tutorials. It provides a useful generator for setting up user authentication in a few simple steps.

It’s worth noting that there are other tools for integrating authentication, for instance technoweenie’s Restful Authentication is very good. However, to keep things simple, we will stick with nifty_generators.

At a command prompt key the following command:-

  > gem install nifty-generators

Generating the Authentication

Authentication

Now, make sure your current directory is set to the project folder of your Rails project and run the following commands:-

  > ruby script/generate nifty_authentication
  > ruby script/generate nifty_layout

The first command creates the relevant files for achieving authentication. The second command creates, among other things, a helper file which is required for some of the authentication view files to function correctly.

Don’t forget to migrate your database!

  > rake db:migrate

Making use of the Authentication Module

Authentication

Ok, so we now have the functionality, which is required for authenticating users, it’s just a matter of using it. First, we will create a partial allowing the user to sign up or login.

Create a file called “_login.html.erb” in the views/users folder and add the following code:

< % if logged_in? %>
  Welcome < %= current_user.username %>! Not you?
  < %= link_to "Log out", logout_path %>
< % else %>
  < %= link_to "Sign up", signup_path %> or
  < %= link_to "log in", login_path %>.

< % end %>

We will simply render the login partial in the “posts.html.erb” layout file (to keep things simple). This file is located in the views/layouts folder. Edit the file to include the “render” method call, as shown below.

.
.
<body>
  <div id="content">
    <p><%= render :partial => "users/login" %></p>

    <%= yield %>
  </div>
</body>
.
.

Further to this, we only want users to be able to post messages if they are logged in so change the “_message_form.html.erb” file, in the views/posts folder, to have the following condition:

<% if logged_in? %>

  <% form_remote_tag(:controller => "posts", :action => "create") do %>
    <%= label_tag(:message, "What are you doing?") %><br />
    <%= text_area_tag(:message, nil, :size => "60x2") %><br /> 
    <%= submit_tag("Update") %>

  <% end %>
<% end %>

Let’s Give it a Go!

Fire up the server.

  > ruby script/server

On the home page we now have “Sign up” and “Login” links.

Sign Up and Login Links

You’ll also notice that you cannot post a message until you have a user account. So you will need to sign up first

Sign Up Form

Then you can login…

Our Twitter login page

Once you have logged in, you will be able to post messages again.

Logged in to our Twitter

View Demo of Twitter App with Ruby on Rails

Summary

In this tutorial, you have leanrt how to integrate authentication into your applications and how to make use of it. In the third and final part of this series you will learn how to add functionality, which allows users to follow other users.

Author: Phil McClure

Phil McClure is a Software Developer from Belfast, Northern Ireland. His main interests are software architecture, design patterns and how these can be applied to web development. Phil blogs at Therailworld. Follow him on Twitter.

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33 comments

  1. The headline is slightly misleading: This is rather a Twitter–like application.
    Reading this headline I had expected to find a tutorial on how to make use of the Twitter API, using RoR.

    Regards,
    trice

  2. Helpful tutorial. But seems to miss couple of pieces here and there – e.x. the _login form does not work as is.

    1. Now I see why the author could not post it properly :-) Read the following code using the legend.

      lt = less than symbol
      pt = percentage symbol

      ltpt if logged_in? ptlt
      Welcome ltpt= current_user.username ptlt! Not you?
      ltpt= link_to “Log out”, logout_path ptlt
      ltpt else ptlt
      ltpt= link_to “Sign up”, signup_path ptlt or
      ltpt= link_to “log in”, login_path ptlt.
      ltpt end ptlt

  3. For some reason I keep getting this message everytime I run the server…

    Routing Error

    uninitialized constant ApplicationController::Authentication

    Can anyone point me in the right direction so that I can continue this awesome tutorial!?!

    1. from my terminal (using ubuntu 9.04)

      ActionController::RoutingError (uninitialized constant ApplicationController::Authentication):
      app/controllers/application_controller.rb:2
      app/controllers/posts_controller.rb:1

      Rendered /usr/lib/ruby/gems/1.8/gems/actionpack-3.0.0/lib/action_dispatch/middleware/templates/rescues/routing_error.erb within rescues/layout (1.8ms)

  4. I was suggested this blog by my cousin. I’m not sure whether this post is written by him as nobody else know such detailed about my difficulty. You are incredible! Thanks!

  5. It is appropriate time to make some plans for the future and it is time to be happy. I’ve read this post and if I could I wish to suggest you some interesting things or advice. Maybe you can write next articles referring to this article. I desire to read more things about it!

  6. Does the create action under session controller does not seem to be working. When I enter wrong username/password, it still redirects me the url localhost:3000/sessions. Did I do something wrong?

  7. For some reason, I ended up with my posts.html.erb file in views/posts and it needs to be in view/layouts. Clearly stated in the tutorial, I’m just confused with how it got there.

  8. Darnit I’m stuck can’t get the nifty_generators to install correctly, I’m on windows7. To bad I can’t finish this tutorial. :(

  9. With Rails3 on nifty-generators now work with a ” : ” instead of ” _ “.
    So, nifty_layout becomes nifty:layout,
    so does with nifty:authentication and nifty:scaffold.

  10. For Rails 3 after you install the nifty-generators, you have to edit the Gemfile adding:
    gem “nifty-generators”, :group => :development

    make sure you “gem install mocha” as well and add this line as well
    “gem “bcrypt-ruby”, :require => “bcrypt””

    Also as Disha said, do “rails g nifty:authentication instead of nift_authentication. Same goes for layout.

    oh, and don’t forget to restart the server! Hope this helps :)

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