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You’re currently reading the article “RESTful Controllers in Ruby on Rails.”
- Published:
- February 18th 07:36 AM
- Updated:
- August 17th 07:47 PM
- Sections:
- Ruby on Rails
RESTful Controllers in Ruby on Rails
The following article describes how to create the basic operations of create, read, update, and destroy on a simple table using RESTful resource scaffolding.
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The following posts are based on a Ruby on Rails workshop I am teaching in Thimphu, Bhutan. It is not a complete tutorial since it does not include explanations. It may in the future but I do not know when I will have time to add them, so I am publishing it now as is to make it available to others that may find it useful. The sketches describe how to progressively build an Image Management System from the ground-up.
Before reading this article it is recommended that you read this first: Hello World! An Introduction to Controllers, Views, and Layouts.
Index
- Creating the MySQL Database
- Creating the Scaffold Controller
- Creating the Table
- Testing the Output
- Changing the Generated Code
Creating the MySQL Database
To create a database, type into the command-line:
mysqladmin -u root create ims_development
Creating the Scaffold Controller
To create the scaffold controller, type into the command-line:
ruby script/generate scaffold_resource country title:string
Output:
exists app/models/
exists app/controllers/
exists app/helpers/
create app/views/countries
exists test/functional/
exists test/unit/
create app/views/countries/index.rhtml
create app/views/countries/show.rhtml
create app/views/countries/new.rhtml
create app/views/countries/edit.rhtml
create app/views/layouts/countries.rhtml
create public/stylesheets/scaffold.css
create app/models/country.rb
create app/controllers/countries_controller.rb
create test/functional/countries_controller_test.rb
create app/helpers/countries_helper.rb
create test/unit/country_test.rb
create test/fixtures/countries.yml
create db/migrate
create db/migrate/001_create_countries.rb
route map.resources :countries
Creating the Table
Restrict the size of the title to 100 and make MyISAM the default database engine for the creation of the table countries by updating db/migrate/001_create_countries.rb to:
class CreateCountries < ActiveRecord::Migration
def self.up
create_table :countries, :options => 'engine=MyISAM' do |t|
t.column :title, :string, :limit => 100
end
end
def self.down
drop_table :countries
end
end
If you are working on a linux box, make sure the sockets are set in config/database.yml; do not include the sockets if you are working on a windows box. Also add utf8 as the encoding (comments have been ignored):
development:
adapter: mysql
database: ims_development
username: root
password:
host: localhost
socket: /var/run/mysqld/mysqld.sock
encoding: utf8
test:
adapter: mysql
database: ims_test
username: root
password:
host: localhost
socket: /var/run/mysqld/mysqld.sock
encoding: utf8
production:
adapter: mysql
database: ims_production
username: root
password:
host: localhost
socket: /var/run/mysqld/mysqld.sock
encoding: utf8
Run the database migration by typing:
rake db:migrate
Output:
== CreateCountries: migrating ==========================
-- create_table(:countries, {:options=>"engine=MyISAM"})
-> 0.1300s
== CreateCountries: migrated (0.1300s) =================
Testing the Output
Test in browser by typing into the address bar:
http://localhost:3000/countries
Create a country and test xml response by typing into the address bar:
http://localhost:3000/countries.xml
and
http://localhost:3000/countries/1
and
http://localhost:3000/countries/1.xml
Changing the Generated Code
To simplify the display of all countries, one can make the country name a link by updating to app/views/countries/index.rhtml to:
<h1>Listing countries</h1>
<table border="1">
<tr>
<th>Title</th>
</tr>
<% for country in @countries %>
<tr>
<td><%= link_to h(country.title), country_path(country) %></td>
</tr>
<% end %>
</table>
<br />
<%= link_to 'New country', new_country_path %>
Now to add a link to destroy to app/views/countries/show.rhtml, update to:
<p>
<b>Title:</b>
<%=h @country.title %>
</p>
<%= link_to 'Edit', edit_country_path(@country) %> |
<%= link_to 'Destroy', country_path(@country), :confirm => 'Are you sure?', :method => :delete %> |
<%= link_to 'Back', countries_path %>
Next recommended article to read: Active Record Associations and Validations with Resouce Mapping
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