Chapter 8: Refining Your Code

Refining Your Model

We refine the User model just to make other files, like controllers and views, simpler, easier to write and read. We will just exclude some of the commonly used stuff and put it into the model, in form of functions. Look at the following code:

app/models/user.rb
class User < ActiveRecord::Base
  attr_accessor :current_password

  validates_presence_of :screen_name, :e_mail, :password
  validates_uniqueness_of :screen_name
  validates_uniqueness_of :e_mail, :case_sensitive => false
  validates_length_of :screen_name, :within => 6..30
  validates_length_of :e_mail, :within => 6..50
  validates_length_of :password, :within => 6..30
  validates_confirmation_of :password
  validates_format_of     :e_mail,     :with => /^[A-Z0-9_.%-]+@([A-Z0-9_]+\.)+[A-Z]{2,4}$/i,
                                       :message => "must be a valid e-mail address"
  validates_presence_of :forename, :surname
  
  def full_name
    [forename, surname].join(' ')
  end
  
  def login!(session)
    session[:user_id] = id
  end
  
  def self.logout!(session)
    session[:user_id] = nil
  end
  
  def self.logged_in?(session)
    session[:user_id] != nil
  end
  
  def self.logged_in(session)
    return nil if not logged_in?(session)
    User.find(session[:user_id])
  end
  
  def update_attributes(attributes)
    if attributes[:password].empty?
      # the user doesn't want to change the password
      attributes[:password] = password
      attributes[:password_confirmation] = password
    elsif attributes[:current_password] != password
      # the user provided incorrect current_password
      errors.add(:current_password, "is incorrect")
      return false
    end
    super(attributes)
  end
end

We have added the following functions:

full_name: Displaying the full name (forename + surname) is quite common, especially in the views. The full_name is not present in the database and therefore is not available as the user member variable, but thanks to the definition of this function you can use expressions like @user.full_name as it were.
login!: This function replaces the session[:user_id] = id that appeared in several places in the user controller. This just slightly influenced the length of the code but, by adding the meaning to the snippets like @user.login!(session) it's contributed the text clarity and understandability. Notice the exclamation mark, used to point out that this function changes the state of the application (from not logged to logged).
logout!: Similar to the previous one. Notice that to logout you do not need any particular instance of user, therefore this function should be used for the whole class, ie. User.logout!(session) rather than @user.logout!(session). Notice the word self just before the name of the function: this tells the Ruby interpreter that this is a class function, not an instance function, and that it should be called for the entire class, not just an individual object.
logged_in?: Another example of a class function. Returns a logical expression which is true if someone is logged in and false if there is no currently logged user.
logged_in: Yet another class function, returns the is of the currently logged user (or nil if none).
update_attributes: This is an overriden function. This means that it was already defined in our class, and we have even used this function from within the user controller. The new, updated (or: overwritten) version of this function additionally pre-processes the password (for the discussion of the password update check Chapter 7), and, after that, it calls it standard (also known as: super) version to update all the attributes.

Look below for some samples of the possible modifications in the code. The first file shows how a sample view template can benefit from the full_name function.

app/views/user/find_by_town.html.erb
<h1>All People in <%= @town %></h1>
<ul>
<% @users.each do |user| %>
  <li><%= link_to user.full_name, 
                :controller => :user,
                :action => :profile,
                :id => user.screen_name %></li>
<% end %>
</ul>

Here is the complete source code of the User Controller with modifications made possible with the new functions defined in the User Model:.

app/controllers/user_controller.rb
class UserController < ApplicationController

  before_filter :protect, :except => [:login, :register, :tech]

  def index
    @title = "User Index"
    @user = User.logged_in(session)
  end

  def register
    @title = "Register"

    if request.post?
      @user = User.new(params[:user])
      if @user.save
        @user.login!(session)
        flash[:notice] = "User with login #{@user.screen_name} created!"
        redirect_to :action => :index
      end
    end
  end

  def login
    @title = "Log in to Fakebook"
  
    if request.post?
      user = User.find_by_screen_name_and_password(params[:user][:screen_name], params[:user][:password])
      if user
        user.login!(session)
        flash[:notice] = "User #{user.screen_name} logged in"
        redirect_to :action => "index"
      else
        flash[:notice] = "Invalid email/password combination"
      end
    end
  end

  def logout
    flash[:notice] = "User " + User.logged_in(session).screen_name + " logged out"
    User.logout!(session)
    redirect_to :controller => :site, :action => :index
  end
  
  def edit
    @title = "Edit Your Details"
    @user = User.logged_in(session)
    if request.post?
      if @user.update_attributes(params[:user])
        flash[:notice] = "Your details have been updated"
        redirect_to :action => :index
      end
    end
    @user.password = nil
    @user.password_confirmation = nil
  end

  def profile
    @screen_name = params[:id]
    @title = "User Profile for #{@screen_name}"
    @user = User.find_by_screen_name(@screen_name)
  end

  def find_by_town
    @town = params[:id]
    @title = "All people from #{@town}"
    @users = User.find(:all, :conditions => "town = '#{@town}'")
  end

private
  # Protect a page against not logged users
  def protect
 	  unless User.logged_in?(session)
      flash[:notice] = "Please login first"
      redirect_to :action => :login
	    return false
	  end
  end
end

Refining User Hub & Profile

To go on smoothly, we can also slightly modify the User Hub and Profile pages. These modifications include a better use of HTML headings and lists. They are quite straightforward and do not require any comment:

app/views/user/index.html.erb
<h1>Hello, <%= @user.full_name %>!</h1>

<h2>Your Details:</h2>
<ul>
<li>Screen name: <%= @user.screen_name %></li>
<li>E-mail address: <%= @user.e_mail %></li>
<li>Occupation: <%= @user.occupation %></li>
<li>
  Town/City: <%= @user.town %>
  (<%= link_to "see all people in your town",
                :controller => :user,
                :action => :find_by_town,
                :id => @user.town %>)
</li>
</ul>
<p><%= link_to "Edit Your Details", :action => :edit %></p>

app/views/user/profile.html.erb
<% if @user %>
  <h1><%= @user.full_name %>: User Profile</h1>

  <h2>Personal Details:</h2>
  <ul>
    <li>Screen name: <%= @user.screen_name %></li>
    <li>Occupation: <%= @user.occupation %></li>
    <li>Town/City: <%= @user.town %></li>
  </ul>
<% else %>
  <h1>No User Profile for: <%= @screen_name %></h1>
<% end %>

Ruby on Rails Tutorial Chapter 8: Refining Your Code

Chapter 8: Refining Your Code

Refining Your Model

Refining User Hub & Profile

Ruby on Rails Tutorial
Chapter 8: Refining Your Code