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


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