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A-Z Intro To Rails

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Notes on slide 1


My name is Robert Dempsey

I’ll be graduating with an MBA from Crummer in August.

Certified ScrumMaster

I’m the CEO of ADS, a web development shop in Orlando

We develop an online suite of apps
Scrum’d: simple project management for agile teams
Expens’d: simple expense tracking
Prioritiz’d: all about getting things done

Find me on Twitter

My wife and daughter are here in Las Vegas


Two quick movies I want to share





A few people commented on our blog
I can provide specific help after the tutorial

Ruby

Created by Yukihiro “matz” Matsumoto

1995 - public release

2006 - gained mass acceptance

Blending of languages: Perl, Smalltalk, Eiffel, Ada, and Lisp

Ranked #10 in the world on the Tiobe index, April 2009

Open source

Everything is an object
Everything can be given it’s own properties (instance variables) and actions (methods)
All types have methods and instance variables
The same rules apply everywhere

Ruby is Flexible
Freely alter Ruby’s parts
Remove, redefine, and extend at will

Ruby is Easy on the Eyes and Brain
Very limited punctuation
Preference for English keywords
Enhanced readability and reduced learning curve


Created by David Heinemeier Hansson
Extracted from Basecamp - 37signals

Released to the public

Full-stack framework for developing database-backed web applications
Uses the Model-View-Controller pattern
Builds on the power of Ruby
Stresses convention over configuration

Productivity gains: smaller teams, faster time to market, more concurrent projects
Code management: less code = easier management
Faster development
Simpler solution for a common problem: web-front end to a database

Data warehousing and data mining
Statistics reporting
Management systems
Collaborative applications
Community sites
E-commerce applications
Content management systems

Open source



A model represents the information (data) of the application and the rules to manipulate that data. In the case of Rails, models are primarily used for managing the rules of interaction with a corresponding database table. In most cases, one table in your database will correspond to one model in your application. The bulk of your application’s business logic will be concentrated in the models.

Views represent the user interface of your application. In Rails, views are often HTML files with embedded Ruby code that performs tasks related solely to the presentation of the data. Views handle the job of providing data to the web browser or other tool that is used to make requests from your application.

Controllers provide the “glue” between models and views. In Rails, controllers are responsible for processing the incoming requests from the web browser, interrogating the models for data, and passing that data on to the views for presentation.

One route in our app

REST
Maps actions to HTTP methods


In the course of building this app I will explain the basics:
Directory structure
Migrations
Models, views, controllers
Routes
More

Generate a Rails app with the Postgres database

Generate a Rails app with the MySQL database

Rails directory structure

This is a brief instruction manual for your application.
Use it to tell others what your application does, how to set it up, and so on.
On GitHub, many devs use this as the home page

This file contains batch jobs that can be run from the terminal.

Contains the controllers, models, and views for your application.
You’ll focus on this folder for the remainder of this tutorial.

Looking into the app directory, where lot’s of our code goes

Configure your application’s runtime rules, routes, database, and more.

Shows your current database schema, as well as the database migrations.

In-depth documentation for your application.

Extended modules for your application (more advanced than we’ll go today)

Application log files.

The only folder seen to the world as-is. This is where your images, javascript, stylesheets (CSS), and other static files go.

Scripts provided by Rails to do recurring tasks, such as benchmarking, plugin installation, and starting the console or the web server.

Unit tests, fixtures, and other test apparatus.

Temporary files

Third-party code.
Gems, plugins, Rails, etc.

Configure the database - Postgres

Configure the database - MySQL

Create the database

Fire up the server
Starts our application in development mode (by default)
Can start the local server in development, testing, or production
* Highly suggest running in production mode for testing OR set up a staging server

Browse to http://localhost:3000
Should see something like this
The default Rails page, located at public/index.html

Remove the public index file


The basic way to create the employer model

Use scaffolding to create an Employer
- Typically you’d get rid of this later
- You’ll need to customize what has been generated
- The better you get, the less scaffold you’ll use

Directories and files created with the generator

The biggies

The table and fields are created when we run this

Run the migration
Since we’re in development, it will be applied to the dev database

Create the default root
We’ll use this later
Uncomment the line in routes.rb and change it

The list page
Create two employers
Update one
Delete one

Our employer model

Our employer model
Add validations: these are two of many

Employer errors

Skinny controller fat model
Jamis Buck - Rails core team member

The controller has the CRUD, and that’s it

Put all logic into the model, not into the controller
Result: better code reuse, keep details in templates, easier testing

The console is a tool that gives us the runtime environment at a command-line
Use it for testing, rather than trying everything in a browser
Can fully interact with a database
Can run in any Rails environment: development, testing, production
Fire it up

Create new objects
Save objects
View errors
Use “reload!” to see updates to your models

We first pull up a list of employers using the index action
Above the action is the REST call
We can have numerous return formats: html, xml, json

Above the action is the REST call

Data return formats
We can have numerous return formats: html, xml, json

Index view

h is a Rails helper method to sanitize displayed data, preventing cross-site scripting attacks

link_to builds a hyperlink to a particular destination

edit_employer_path is a helper that Rails provides as part of RESTful routing.
You’ll see a variety of these helpers for the different actions that the controller includes.

Employer layout
<%= yield %> is where views get rendered into
The scaffold generator creates a default layout for each model
We can create a master layout that is applied to all, and either have a per-model layout, or remove them

First, create a new employer first by showing the new form
Instantiate a new employer

New view
Form helpers
error messages, label, text field, submit

The employer is then created by the create action

Next we show the employer
This shows only a single employer

Show view

If we want to edit the employer we retrieve the employer using the edit action

Edit view

The update action actually updates the record

The destroy action will remove the employer from the database


The new and edit forms have the same form fields

Name the partial
In the same view folder as all the other employer stuff
The “_” indicates it’s a partial

The new partial

Render the partial
Can render partials that are in any folder



Can render partials that are in any folder by specifying the folder and the partial name

Duplicates in the show, edit, update, and delete methods

Put it all into a before filter
Before filters run before actions
After filters run after actions
Put this code underneath the controller declaration


The code for the before_filter
Put it at the bottom of the controller above the last end


Use scaffolding to create a Job
Created our model, our views, and our controller

Job migration

Run the migration

Model relationships

Belongs_to association
One-to-one connection
Each job can be assigned to only one employer

Has_one association
One-to-one connection
* Used if an employer had one and only one job

Has_many association
The other side of the belongs_to association
One-to-many connection
Each instance of employer has 0 or more jobs

Has_many through association
Many-to-many connection
The third model sets up the association

Has_and_belongs_to_many association
Many-to-many connection

Our job model

Our job model

Our job model

Our updated employer model with the connection to the jobs

Create jobs as a nested resource within employers


Just like with the Employer controller, create a before filter on the Jobs controller


The code for the before_filter
Put it at the bottom of the controller above the last end


Index action to create a job

Index view

Create a new job as a resource of an Employer

This creates a new Job object and sets up the employer_id field to have the id from the specified Employer object in a single operation

New view

Create action

Show the job

Show view

If we want to edit the job we retrieve the job using the edit action

Edit view

The update action actually updates the record

The destroy action will remove the job from the database

Hook the employer and it’s jobs together
Update the show view for employers
Each employer has it’s own jobs collection

Now we can see the employer and get to their jobs

And we can see the list of jobs for the employer, and CRUD them.

Add a simple search form to our index page

Simple employer search
Search form added to employers/index.html.erb

Update the index method


Keep the search in the box
Updated search form
Shows our query in the search box


Updated index action
@query allows us to capture information and use it in a form









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A-Z Intro To Rails - Presentation Transcript

  1. Hello
  2. Robert Dempsey
  3. adsdevshop.com
  4. adsdevshop.com/apps
  5. rdempsey
  6. A-Z Intro To Ruby on Rails
  7. Always Be Learning
  8. Teach Others
  9. Be Bold
  10. Whatʼs Going On • Introduction to Ruby • Introduction to Rails • Hands-on Lab • Breaks interspersed
  11. Ruby
  12. 1995
  13. 2006
  14. Perl SmallTalk Eiffel Ada + Lisp Ruby
  15. #10 baby!
  16. 5.times { print “We love Ruby” }
  17. class Numeric def plus(x) self.+(x) end end y = 5.plus 6 # y is now equal to 11
  18. Rails
  19. 2005
  20. Image copyright 2008 Yoshiko314 (Flickr)
  21. MVC
  22. Model View Controller
  23. Model View Controller
  24. Model View Controller
  25. Model View Controller
  26. map.root :controller => ʻemployersʼ
  27. Action HTTP Method URL XML index GET /jobs /jobs.xml show GET /jobs/1 /jobs/1.xml new GET /jobs/new edit GET /jobs/1;edit create POST /jobs /jobs.xml update PUT /jobs/1 /jobs/1.xml destroy DELETE /jobs/1 /jobs/1.xml
  28. Letʼs Build Something
  29. The Project • Employers • Jobs
  30. rails jobby -d postgresql
  31. rails jobby -d mysql
  32. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  33. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  34. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  35. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  36. app/ controllers/ helpers/ models/ views/
  37. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  38. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  39. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  40. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  41. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  42. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  43. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  44. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  45. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  46. README Rakefile app/ config/ db/ doc/ lib/ log/ public/ script/ test/ tmp/ vendor/
  47. development: adapter: postgresql encoding: unicode database: jobby_development pool: 5 username: root password: config/database.yml
  48. development: adapter: mysql encoding: utf8 database: jobby_development pool: 5 username: root password: socket: /tmp/mysql.sock config/database.yml
  49. rake db:create
  50. script/server
  51. rm public/index.html
  52. map.connect ʻ:controller/:action/:idʼ map.connect ʻ:controller/:action/:id.:formatʼ config/routes.rb
  53. script/generate model Employer
  54. script/generate scaffold Employer name:string address:string city:string state:string zipcode:string
  55. exists app/models/ exists app/controllers/ exists app/helpers/ create app/views/employers exists app/views/layouts/ exists test/functional/ exists test/unit/ create test/unit/helpers/ exists public/stylesheets/ create app/views/employers/index.html.erb create app/views/employers/show.html.erb create app/views/employers/new.html.erb create app/views/employers/edit.html.erb create app/views/layouts/employers.html.erb create public/stylesheets/scaffold.css create app/controllers/employers_controller.rb create test/functional/employers_controller_test.rb create app/helpers/employers_helper.rb create test/unit/helpers/employers_helper_test.rb route map.resources :employers dependency model exists app/models/ exists test/unit/ exists test/fixtures/ create app/models/employer.rb create test/unit/employer_test.rb create test/fixtures/employers.yml create db/migrate create db/migrate/20090501175821_create_employers.rb
  56. app/models/employer.rb db/migrate/20090...1_create_employers.rb app/views/employers/index.html.erb app/views/employers/show.html.erb app/views/employers/new.html.erb app/views/employers/edit.html.erb app/views/layouts/employers.html.erb public/stylesheets/scaffold.css app/controllers/employers_controller.rb app/helpers/employers_helper.rb test/functional/employers_controller_test.rb test/unit/helpers/employers_helper_test.rb test/unit/employer_test.rb test/fixtures/employers.yml route map.resources :employers
  57. class CreateEmployers < ActiveRecord::Migration def self.up create_table :employers do |t| t.string :name t.string :address t.string :city t.string :state t.string :zipcode t.timestamps end end def self.down drop_table :employers end end db/migrations/2009...create_employers.rb
  58. rake db:migrate
  59. map.root :controller => ʻemployersʼ config/routes.rb
  60. http://localhost:3000/
  61. class Employer < ActiveRecord::Base end app/models/employer.rb
  62. class Employer < ActiveRecord::Base validates_presence_of :name validates_length_of :city, :minimum => 3 end app/models/employer.rb
  63. http://localhost:3000/employers/new
  64. Controller => CRUD
  65. Model => Logic
  66. script/console
  67. # GET /employers # GET /employers.xml def index @employers = Employer.all respond_to do |format| format.html # index.html.erb format.xml { render :xml => @employers } end end app/controllers/employers_controller.rb
  68. # GET /employers # GET /employers.xml def index @employers = Employer.all respond_to do |format| format.html # index.html.erb format.xml { render :xml => @employers } end end app/controllers/employers_controller.rb
  69. # GET /employers # GET /employers.xml def index @employers = Employer.all respond_to do |format| format.html # index.html.erb format.xml { render :xml => @employers } end end app/controllers/employers_controller.rb
  70. app/views/employers/index.html.erb
  71. <%=h employer.name %> app/views/employers/index.html.erb
  72. <%= link_to 'New employer', ... %> app/views/employers/index.html.erb
  73. edit_employer_path(employer) app/views/employers/index.html.erb
  74. app/views/layouts/employers.html.erb
  75. # GET /employers/new # GET /employers/new.xml def new @employer = Employer.new respond_to do |format| format.html # new.html.erb format.xml { render :xml => @employer } end end app/controllers/employers_controller.rb
  76. app/views/employers/new.html.erb
  77. # POST /employers # POST /employers.xml def create @employer = Employer.new(params[:employer]) respond_to do |format| if @employer.save flash[:notice] = 'Employer was successfully created.' format.html { redirect_to(@employer) } format.xml { render :xml => @employer, :status => :created, :location => @employer } else format.html { render :action => \"new\" } format.xml { render :xml => @employer.errors, :status => :unprocessable_entity } end end end app/controllers/employers_controller.rb
  78. # GET /employers/1 # GET /employers/1.xml def show @employer = Employer.find(params[:id]) respond_to do |format| format.html # show.html.erb format.xml { render :xml => @employer } end end app/controllers/employers_controller.rb
  79. app/views/employers/show.html.erb
  80. # GET /employers/1/edit def edit @employer = Employer.find(params[:id]) end app/controllers/employers_controller.rb
  81. app/views/employers/edit.html.erb
  82. # PUT /employers/1 # PUT /employers/1.xml def update @employer = Employer.find(params[:id]) respond_to do |format| if @employer.update_attributes(params[:employer]) flash[:notice] = 'Employer was successfully updated.' format.html { redirect_to(@employer) } format.xml { head :ok } else format.html { render :action => \"edit\" } format.xml { render :xml => @employer.errors, :status => :unprocessable_entity } end end end app/controllers/employers_controller.rb
  83. # DELETE /employers/1 # DELETE /employers/1.xml def destroy @employer = Employer.find(params[:id]) @employer.destroy respond_to do |format| format.html { redirect_to(employers_url) } format.xml { head :ok } end end app/controllers/employers_controller.rb
  84. Donʼt Repeat Yourself
  85. Partials
  86. _form.html.erb app/views/employers/_form.html.erb
  87. app/views/employers/_form.html.erb
  88. <%= render :partial => 'form' %>
  89. app/views/employers/new.html.erb
  90. app/views/employers/edit.html.erb
  91. <%= render :partial => 'shared/form' %>
  92. @employer = Employer.find(params[:id]) app/controllers/employers_controller.erb
  93. before_filter :find_employer, :only => [:show, :edit, :update, :destroy] app/controllers/employers_controller.rb
  94. app/controllers/employers_controller.rb
  95. private def find_employer @employer = Employer.find(params[:id]) end app/controllers/employers_controller.rb
  96. app/controllers/employers_controller.rb
  97. script/generate scaffold Job name:string description:text
  98. class CreateJobs < ActiveRecord::Migration def self.up create_table :jobs do |t| t.integer :employer_id t.string :name t.text :description t.timestamps end end def self.down drop_table :jobs end end db/migrations/2009...create_jobs.rb
  99. rake db:migrate
  100. belongs_to has_one has_many has_many :through has_one :through has_and_belongs_to_many
  101. jobs employers Model: Job Model: Employer belongs_to :employer has_many :jobs id integer id integer employer_id integer name string name string address string
  102. employers jobs Model: Employer Model: Job has_one :job belongs_to :employer id integer id integer name string employer_id integer address string name string
  103. employers jobs Model: Employer Model: Job has_many :jobs belongs_to :employer id integer id integer name string employer_id integer address string name string
  104. physicians Model: Physician has_many :appointments has_many :patients, :through => :appointments appointments id integer Model: Appointment name string belongs_to :physician belongs_to :patient id integer patients physician_id integer Model: Patient patient_id integer has_many :appointments has_many :physicians, :through => :appointments id integer name string
  105. physicians Model: Physician has_and_belongs_to_many :patients id integer physicians_patients name string physician_id integer patients patient_id integer Model: Patient has_and_belongs_to_many :physicians id integer name string
  106. class Job < ActiveRecord::Base end app/models/job.rb
  107. class Job < ActiveRecord::Base belongs_to :employer validates_presence_of :name validates_presence_of :description end app/models/job.rb
  108. class Job < ActiveRecord::Base belongs_to :employer validates_presence_of :name validates_presence_of :description end app/models/job.rb
  109. class Employer < ActiveRecord::Base has_many :jobs validates_presence_of :name validates_length_of :city, :minimum => 3 end app/models/employer.rb
  110. map.resources :employers map.resources :employers, :has_many => :jobs map.resources :jobs app/controllers/employers_controller.rb
  111. before_filter :find_employer app/controllers/jobs_controller.rb
  112. app/controllers/jobs_controller.rb
  113. private def find_employer @employer = Employer.find(params[:employer_id]) end app/controllers/jobs_controller.rb
  114. app/controllers/jobs_controller.rb
  115. # GET /jobs # GET /jobs.xml def index @jobs = @employer.jobs respond_to do |format| format.html # index.html.erb format.xml { render :xml => @jobs } end end app/controllers/jobs_controller.rb
  116. # GET /jobs/new # GET /jobs/new.xml def new @job = Job.new @job = @employer.jobs.build respond_to do |format| format.html # new.html.erb format.xml { render :xml => @job } end end app/controllers/jobs_controller.rb
  117. @job = @employer.jobs.build
  118. app/views/jobs/index.html.erb
  119. # POST /jobs # POST /jobs.xml def create @employer = Employer.find(params[:employer_id]) @job = @employer.jobs.build(params[:job]) respond_to do |format| if @job.save flash[:notice] = 'Job was successfully created.' format.html { redirect_to employer_job_url(@employer, @job) } format.xml { render :xml => @job, :status => :created, :location => @job } else format.html { render :action => \"new\" } format.xml { render :xml => @job.errors, :status => :unprocessable_entity } end end end app/controllers/jobs_controller.rb
  120. # GET /jobs/1 # GET /jobs/1.xml def show @job = @employer.jobs.find(params[:id]) respond_to do |format| format.html # show.html.erb format.xml { render :xml => @job } end end app/controllers/jobs_controller.rb
  121. app/views/jobs/show.html.erb
  122. # GET /jobs/1/edit def edit @job = @employer.jobs.find(params[:id]) end app/controllers/jobs_controller.rb
  123. app/views/jobs/edit.html.erb
  124. # PUT /jobs/1 # PUT /jobs/1.xml def update @job = Job.find(params[:id]) respond_to do |format| if @job.update_attributes(params[:job]) flash[:notice] = 'Job was successfully updated.' format.html { redirect_to employer_job_url(@employer, @job) } format.xml { head :ok } else format.html { render :action => \"edit\" } format.xml { render :xml => @job.errors, :status => :unprocessable_entity } end end end app/controllers/jobs_controller.rb
  125. # DELETE /jobs/1 # DELETE /jobs/1.xml def destroy @job = Job.find(params[:id]) @job.destroy respond_to do |format| format.html { redirect_to employer_jobs_url(@employer) } format.xml { head :ok } end end app/controllers/jobs_controller.rb
  126. app/views/employers/show.html.erb
  127. app/views/jobs/index.html.erb
  128. app/views/jobs/index.html.erb
  129. app/views/employers/index.html.erb
  130. app/views/employers/index.html.erb
  131. app/controllers/employers_controller.rb
  132. app/controllers/employers_controller.rb
  133. app/views/employers/index.html.erb
  134. app/views/employers/index.html.erb
  135. app/controllers/jobs_controller.rb
  136. app/controllers/employers_controller.rb
  137. app/views/employers/index.html.erb
  138. Next Steps
  139. DRY up our Job views Add search to our jobs Add a logins for employers Add tags to our jobs
  140. Resources
  141. Rails Guides Agile Web Development (PP) Intro to Ruby 1.9 Cucumber + RSpec
  142. Contest!
  143. Letʼs Chat

+ Robert DempseyRobert Dempsey, 6 months ago

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