armstrongnate / codeschool_todo

The slideshows can be found here: http://tinyurl.com/losrh8l

Getting started with our Todo app

bin/rails new todo

cd todo/

bin/rails generate model User name:string email:string

You should have a new model file with the following code:

class User < ActiveRecord::Base
end

At this point we have created the migration file but we still have to run the migration. To run migrations type:

bin/rake db:migrate

If this is the first time you have run the migration you should get an output to the console saying a users table was created.

Test your new User model:

The rails console allows you to interact with your ruby classes within the rails environment.

In your terminal type:

bin/rails console

This will launch the console. Once you are in the console type:

User.first

That should return nil.

To create a a new user type:

User.create(name: 'Nate', email: '[email protected]')

Now you should be able to get the first user:

User.first

Play!

# get a user
user = User.first
user.name # should print the name you set previously
user.email # should print the email you set previously

# update user
user = User.first
user.name = 'Bob'
user.save # should print true

# delete a user
user = User.first
user.destroy # should print true

# create a new user
user = User.new
user.name = 'John'
user.email = '[email protected]'
user.save

Validations

We can validate that a user must always have a name

# app/models/user.rb
class User < ActiveRecord::Base
  validates :name, presence: true
end

• NOTE: if you change something in the model file you must reload your console in order for it to pick up on the changes. *

From the console run:

reload!

Now test the new validation:

user = User.create(email: '[email protected]')

The above line should return false because we did not include a name.

You can test to see if a record is valid or not with:

user.valid?

In our case this should return false. Why?

Rails allows us to view any errors on a record that might be present.

user.errors

This will tell us that the name field can not be blank.

Associations

In this app, a user will have many tasks. So let's create a new Task model that belongs to a user.

Back in the terminal (exit the rails console by typing exit)

bin/rails generate model Task title user:references

This created a few files, one main one being the migration file. So, let's run our migrations.

bin/rake db:migrate

Now we have a tasks table. We must define the relationship within the model classes.

Open up app/models/task.rb and app/models/user.rb files and make them look like this:

# app/models/task.rb
class Task < ActiveRecord::Base
  belongs_to :user
end

# app/models/user.rb
class User < ActiveRecord::Base
  has_many :tasks
  validates :name, presence: true
end

Test the association by opening the console again (bin/rails console). You should now be able to get a users tasks.

User.first.tasks

The above code should return an empty array since you have not created any tasks.

• Note: Ensure that you have at least one user by running User.count. If the number is zero create a new user (see above). *

Create a new task that belongs to a user

In the console:

user = User.first
Task.create(title: 'Demo', user: user)

Now our first user has one task. Confirm by typing:

User.first.tasks

That should return an array with one task.

Add a new column to a table

We want want a way to keep track of whether or not a task has been completed or not. Let's add a completed column to our tasks table.

Exit the console and type the folling into the terminal.

bin/rails generate migration AddCompletedToTasks completed:boolean

Now if you look in db/migrate directory there will be a new file created that should look like:

class AddCompletedToTasks
  add_column :tasks, :completed, :boolean
end

To test that this new column exists, boot up the rails console and type the following:

Task.first.completed

• NOTE: You should have at least one task created. *

We can update this column in the console like so:

task = Task.first
task.update_attributes(completed: true)

Users Controller

Generate a controller for the User model.

bin/rails generate controller Users

Start a rails server:

bin/rails server

Users Controller Index

Open your rails app in a browser at http://localhost:3000/users - You'll get an error that no route matches /users.

Open config/routes.rb and add a route.

Rails.application.routes.draw do
  get '/users' => 'users#index'
end

Open app/controllers/users_controller.rb and add an index action.

class UsersController < ApplicationController
  def index
    @users = User.all
  end
end

Create a file app/views/users/index.html.erb

<p>Number of users: <%= @users.count %></p>

<ul>
  <% @users.each do |user| %>
    <li>
      <%= user.name %>
      <%= user.email %>
    </li>
  <% end %>
</ul>

Users Controller Show

Open config/routes.rb and add a users#show route:

get '/users/:id' => 'users#show', as: 'user'

Run bin/rake routes to see a list of our routes.

Open app/views/users/index.html.erb and link the user.

<p>Number of users: <%= @users.count %></p>

<ul>
  <% @users.each do |user| %>
    <li>
      <%= user.name %>
      <%= user.email %>
      <%= link_to 'Show', user %>
    </li>
  <% end %>
</ul>

Open app/controllers/users_controller.rb and add a show action.

def show
  @user = User.find(params[:id])
end

Create a file app/views/users/show.html.erb

<h1>Showing <%= @user.name %></h1>
<p><%= @user.email %></p>

Users Controller New

Open config/routes.rb and add a users#show route:

get '/users/new' => 'users#new'

pen app/views/users/index.html.erb and link the new action.

<p><%= link_to 'New User', users_new_path %></p>

Open app/controllers/users_controller.rb and add a new action.

def new
  @user = User.new
end

Create a file app/views/users/new.html.erb

<h1>New User</h1>

<%= form_for @user do |f| %>
  <p>
    <%= f.label :name %>
    <%= f.text_field :name, placeholder: 'Your Name' %>
  </p>

  <p>
    <%= f.label :email %>
    <%= f.text_field :email, placeholder: 'Your Email' %>
  </p>

  <p><%= f.submit %></p>
<% end %>