Install Rails
gem install rails
rails new blog -d postgresql
cd blog
rails db:create
Start the Rails Server
rails server
Routes
Open the file config/routes.rb
in your editor.
Rails.application.routes.draw do
root 'articles#index'
end
To see your work:
rake routes
Create a controller: (controller names are plural)
touch app/controllers/articles_controller.rb
Add a method for each RESTful action.
class ArticlesController < ApplicationController
def index
end
def show
end
def new
end
def edit
end
def create
end
def update
end
def destroy
end
end
(view directory names are plural, file names are normally singular)
mkdir app/views/articles
touch app/views/articles/index.html.erb
touch app/views/articles/new.html.erb
Add this code into app/views/articles/index.html.erb
<h1>hello world</h1>
Try it out
Add this code into app/views/articles/new.html.erb
<%= form_with scope: :article, url: articles_path, local: true do |form| %>
<p>
<%= form.label :title %><br>
<%= form.text_field :title %>
</p>
<p>
<%= form.label :text %><br>
<%= form.text_area :text %>
</p>
<p>
<%= form.submit %>
</p>
<% end %>
Add the route to config/routes.rb
get '/articles/new' => 'articles#new', as: 'new_article'
Change the create method to output the params being sent to it:
def create
render plain: params[:article].inspect
end
Add the route to config/routes.rb
post '/articles' => 'articles#create'
Try it out in the browser:
http://localhost:3000/articles/new
Create the table:
rails generate migration articles
Look inside the generated file:
class Articles < ActiveRecord::Migration
def change
end
end
Inside the change
method add your table creation code:
create_table :articles do |t|
t.string :title
t.text :text
t.timestamps
end
Run the migration
rails db:migrate
Create the model
touch app/models/article.rb (model filenames are singular)
class Article < ActiveRecord::Base
# AR classes are singular and capitalized by convention
end
Start saving things in the controller:
def create
@article = Article.new(article_params)
@article.save
redirect_to @article
end
At the bottom of the file put the private article_params security method:
private
def article_params
params.require(:article).permit(:title, :text)
end
Add to the show controller
def show
@article = Article.find(params[:id])
end
Create a new file app/views/articles/show.html.erb with the following content:
<p>
<strong>Title:</strong>
<%= @article.title %>
</p>
<p>
<strong>Text:</strong>
<%= @article.text %>
</p>
Also add a link to go back to the index action as well, so that people who are viewing a single article can go back and view the whole list:
<%= link_to 'Back', root_path %>
Add the route to the config/routes.rb file
get '/articles/:id' => 'articles#show' , as: 'article'
Add to the index controller
def index
@articles = Article.all
end
Add the view for this action, located at app/views/articles/index.html.erb
<h1>Listing articles</h1>
<table>
<tr>
<th>Title</th>
<th>Text</th>
<th></th>
</tr>
<% @articles.each do |article| %>
<tr>
<td><%= article.title %></td>
<td><%= article.text %></td>
<td><%= link_to 'Show', article_path(article) %></td>
</tr>
<% end %>
</table>
Add this "New Article" link to app/views/articles/index.html.erb placing it above the
<%= link_to 'New article', new_article_path %>
Add another link in app/views/articles/new.html.erb underneath the form, to go back to the index action:
<%= form_with scope: :article, url: articles_path, local: true do |form| %>
...
<% end %>
<%= link_to 'Back', root_path %>
Editing
Add an edit action to the ArticlesController
def edit
@article = Article.find(params[:id])
end
create the route
get '/articles/:id/edit' => 'articles#edit', as: 'edit_article'
Create a file called app/views/articles/edit.html.erb
<h1>Edit article</h1>
<%= form_with scope: :article, model: @article, local: true do |form| %>
<p>
<%= form.label :title %><br>
<%= form.text_field :title %>
</p>
<p>
<%= form.label :text %><br>
<%= form.text_area :text %>
</p>
<p>
<%= form.submit %>
</p>
<% end %>
<%= link_to 'Back', root_path %>
Add the route to the config/routes.rb file
patch '/articles/:id' => 'articles#update'
Create the update action in app/controllers/articles_controller.rb
def update
@article = Article.find(params[:id])
@article.update(article_params)
redirect_to @article
end
Add the edit link to app/views/articles/index.html.erb to make it appear next to the "Show" link:
<td><%= link_to 'Edit', edit_article_path(article) %></td>
Also add one to the app/views/articles/show.html.erb template as well
<%= link_to 'Edit', edit_article_path(@article) %>
Deleting
Add the route to the config/routes.rb file
delete '/articles/:id' => 'articles#destroy'
Add the delete controller to app/controllers/articles_controller.rb
def destroy
@article = Article.find(params[:id])
@article.destroy
redirect_to root_path
end
Add a 'Destroy' link to your index action template, inside the loop (app/views/articles/index.html.erb)
<td><%= link_to 'Destroy', article_path(article),
method: :delete,
data: { confirm: 'Are you sure?' } %></td>
Pairing Exercise
Run the above code.