Ruby on Rails 101

101
1.9.2

Ruby
on
3.0.5
Rails

@claytonlz - Desert Code Camp 2011.1 - http://spkr8.com/t/7007

Saturday, April 2, 2011

Ecosystem
Models
Controllers
Views
Deploying & Optimizing
Resources for Learning


Community


“This sure is a nice fork,
I bet I could… HOLY
SHIT A KNIFE!”


Opinionated


“I flippin’ told you MVC
is the only way to build
web apps! Teach you to
doubt DHH!”


Rapid
Development

“These goats are okay,
but I really need a yak
for some quality shaving”


Ecosystem
Models
Controllers
Views
Deploying


Models

Associations
Validations
Callbacks
Querying


Models

ActiveRecord::Base
class Product < ActiveRecord::Base
... products
end
name string

sku string

price decimal


Models ➤ Associations
# manufacturer ingredients
has_many :products

# product
has_one :upc
belongs_to :manufacturer
has_many :batches batches
has_many :ingredients,
:through => :batches

# batch
belongs_to :product products
belongs_to :ingredient

# ingredient
has_many :batches
has_many :products,
:through => :batches upcs manufacturers



# create a product and find its manufacturer
product = manufacturer.products.create({:name => "Kitlifter"})
product.manufacturer

# create a upc and find its product's manufacturer
upc = product.create_upc({:code => "001122"})
upc.product.manufacturer

# create a batch (linking a product and ingredient)
wheat = Ingredient.create({:name => "Wheat"})
bread = Product.create({:name => "Bread"})

batch.create({:product => bread, :ingredient => wheat})



When should I use has_one
and belongs_to?

“Using has_many or belongs_to is more than
just on which table the foreign key is placed,
itʼs a matter of who can be thought of as
ʻowningʼ the other. A product ʻownsʼ a UPC.”


Models ➤ Validations

class Product < ActiveRecord::Base
validates_presence_of :name
validates_uniqueness_of :name
validates_format_of :sku, :with => /^SKUd{8}$/
validates_inclusion_of :usda_rating, :in => %w( prime choice )

validate :cannot_be_active_if_recalled

def cannot_be_active_if_recalled
if recalled? && recalled_on < Date.today
errors.add(:active, "Can't be active if it's been recalled")
end
end



I know my record is
technically invalid, but
I want to save it anyhow.

“It is possible to save a record,
without validating, by using
save(:validate => false)”


Models ➤ Callbacks

class Ingredient
Callback
before_destroy :determine_destroyability Chain
before_create :format_legacy_name
after_update :log_changes
after_create :import_harvest_data
determine_destroyability
# validation
# create
# save
# update
# destroy

end
STOP!!


Models ➤ Querying

Product.find(98)
Product.find_by_name("Diet Coke")
Product.find_by_name_and_sku("Diet Coke", "SKU44387")
Product.find([98,11,39])
Product.first
Product.last
Product.all
Product.count

# old and busted
Product.find(:all, :conditions => {:name => "Cheese-it!"})

# new hotness
Product.where(:name => "Cheese-it!").all


Models ➤ Querying
Product.where("name = ?", 'Skittles')
Product.where(:created_at => Date.yesterday..Date.today)
Product.where(:sku => ["SKU912", "SKU187", "SKU577"])

Product.order('name DESC')

Product.select('id, name')

Product.limit(5)

# chainable
Product.where(:created_at => Date.yesterday..Date.today)
.limit(10)

Product.order('created_at ASC').limit(20).offset(40)

Product.select('created_at').where(:name => 'Twix')


Models ➤ Querying
manufacturer.includes(:products)
.where('products.usda_rating = ?', 'prime')

manufacturer.includes(:products)
.where(:state => 'AZ')
.order('created_at')

manufacturer.includes(:products => :ingredients)
.where('ingredients.name = ?', 'glucose')
.order('updated_at')

manufacturer.joins(:products)
.where('products.sku = ?', 'SKU456')

ingredient.includes(:products => {:manufacturer => :conglomerate})
.where('conglomerates.name = ?', 'nestle')

animalia.includes(:phylum => {:class => {:order => {:family => :genus}}})

child.includes(:parent => [:brother, {:sister => :children}])



Why would I use joins
instead of includes?

“Using includes will load the
records into memory when the query
is executing, joins will not.”


Controllers

Routing
Filters
Conventions


Controllers ➤ Routing
resources :products
# GET /products => index action
# GET /products/new => new action
# GET /products/:id => show action
# GET /products/:id/edit => edit action
#
# POST /products => create action
#
# PUT /products/:id => update action
#
# DELETE /products/:id => destroy action

products_path # /products
products_url # http://www.example.com/products

product_path(@product) # /products/29
product_path(@product, :xml) # /products/29.xml


namespace :admin do
resources :users
resources :orders
end

admin_users_path # /admin/users
edit_admin_order_path # /admin/orders/4/edit

class Admin::UsersController < ApplicationController
# /app/controllers/admin/users_controller.rb
# /app/views/admin/users/
end


resources :accounts, :except => :destroy do
resources :users do
post :activate, :on => :member
collection do
get 'newest'
end
end

resources :clients, :only => [:index, :show]
end

account_users_path(@account) # /accounts/182/users
newest_account_users_path(@account) # /accounts/182/users/newest
activate_account_user_path(@account, @user) # /accounts/182/user/941

accounts_clients_path(@account) # /accounts/182/clients
new_accounts_client_path(@account) # FAIL!


Controllers ➤ Filters
class UsersController < ApplicationController
before_filter :load_manufacturer
before_filter :find_geo_data, :only => [:show]
skip_before_filter :require_login

after_filter :log_access
end

# in ApplicationController
def log_access
Rails.logger.info("[Access Log] Users Controller access at #{Time.now}")
end


Controllers ➤ Conventions
class ProductsController < ApplicationController
def index
# GET /products
end def update
def show
# GET /products/:id
end
☹ # ... update occurred
@parent.children.each ...
end
def new
# GET /products/new
end
def edit
def create @product = Product.find(params[:id])
# POST /products end

☹
end
def show
def edit @product = Product.find(params[:id])
# GET /products/:id/edit
end
end
def destroy
def update
# PUT /products/:id @product = Product.find(params[:id])
end end

def destroy
# DELETE /products/:id
end
end
☺ before_filter :load_product


Controllers ➤ Conventions
class ProductsController < ApplicationController
def index
# GET /products
end
def update

☹
def show
# GET /products/:id
# ... update occurred
# renders /app/views/products/show.format @parent.children.each ...
end end
def new
# GET /products/new
end
def edit
def create @product = Product.find(params[:id])
# POST /products end

☹
redirect_to products_url
end def show
@product = Product.find(params[:id])
def edit
end
# GET /products/:id/edit
end
def destroy
def update @product = Product.find(params[:id])
# PUT /products/:id end
end

def destroy
# DELETE /products/:id
end
☺ before_filter :load_product

end


Views

Layouts & Helpers
Forms
Partials
ActionView Helpers


Views ➤ Layouts & Helpers

def show
@product = Product.find(params[:id])
end M C

<h2><%= @product.name %></h2>

V
<p>Price: <%= @product.price %></p>


<div id="container">
<%= yield %>
</div>

<div id="container">
<h2>Pop-Tarts</h2>
<p>Price: $3.99</p>
</div>

Views ➤ Layouts & Helpers
<p>Price: <%= number_to_currency(@product.price) %></p>
<p>Ingredients: <%= @product.ingredients.present? ? @product.ingredients.map(&:name).join(',') : 'N/A' %></p>

# app/helpers/products_helper.rb
def display_ingredients(ingredients)
return "N/A" if ingredients.blank?
ingredients.map(&:name).join(',')
end

<p>Price: <%= number_to_currency(@product.price) %></p>
<p>Ingredients: <%= display_ingredients(@product.ingredients) %></p>


Views ➤ Forms
<%= form_tag search_path do %>
<p>
<%= text_field_tag 'q' %><br />
<%= submit_tag('Search') %>
</p>
<% end %>

<form action="/search" method="post">
<p>
<input type="text" name="q" value="" id="q" />
<input type="submit" name="commit_search" value="Search" id="commit_search" />
</p>
</form>


Views ➤ Forms
<h2>New Product</h2>
<%= form_for(@product) do |f| %>


← New Record
<p>
<%= f.text_field :name %>
</p>
<p>
<%= f.check_box :active %> <h2>Edit Product</h2>
</p> <%= form_for(@product) do |f| %>
<% end %> 


<p>
<%= f.text_field :name %>
Existing Record → </p>
<p>
<%= f.check_box :active %>
</p>
<% end %>

Views ➤ Forms

<%= f.hidden_field :secret %>
<%= f.password_field :password %>
<%= f.label :name, "Product Name" %>
<%= f.radio_button :style, 'Clear' %>
<%= f.text_area, :description %>
<%= f.select :condition, ["Good", "Fair", "Bad"] %>

<%= f.email_field :user_email %>
<%= f.telephone_field :cell_number %>


Views ➤ Partials
<% @products.each do |product| %>
<tr><td><%= link_to(product.title, product_path(product)) %></td></tr>
<% end %>

<% @products.each do |product| %>
<%= render :partial => 'product_row', :locals => {:product => product} %>
<% end %>


<tr><td><%= link_to(product.title, product_path(product)) %></td></tr>

<%= render :partial => 'product_row', :collection => @products, :as => :product %>

Views ➤ Partials

<ul>
<li>...</li>
<li>...</li>
</ul>


<%= render :partial => 'shared/recent_changes' %>


<%= render :partial => 'shared/recent_changes' %>

<%= render :partial => @product %>
<%= render(@product) %>

<%= render 'bio', :person => @john %>

Views ➤ Partials

NumberHelper
TextHelper
FormHelper
JavaScriptHelper
DateHelper
UrlHelper
CaptureHelper
SanitizeHelper


Deploying & Optimizing

Heroku
Passenger
NewRelic


Video
PeepCode
RailsCasts
CodeSchool
Books
The Rails Way
Beginning Ruby
Ruby for _________
Other
PHX Rails User Group
Gangplank


@claytonlz
http://spkr8.com/t/7007


Ruby on Rails 101

Recommended

Recommended

More Related Content

Viewers also liked

Viewers also liked (11)

Similar to Ruby on Rails 101

Similar to Ruby on Rails 101 (20)

Recently uploaded

Recently uploaded (20)

Ruby on Rails 101