OnRails.org

The Rails Way Jamis Buck, Michael Koziarski

See the http://therailsway.com/

#railsway on irc.freenode.net for questions at the end of the presentation.

class TheRailsWay < BLog
 authored_by :jamis
 authored_by :koz
end

Instead of teaching you how to build things in Rails, Jamis and Koz will show us they things should be built.

• The Fat controller (Anti-pattern). Use Skinny Controller instead . Move logic out of controller to Model (i.e total_invoice), easier to test, can use form_for, …

• With Scope. Is always abused. Step back and think “Is there a simpler way than using with_scope?”. I.e. implement an accessor to the attribute you need in your scope instead of using with_scope. I.e. current_organization. If the fix is worth than the initial desease don’t do it.

  attr_read :current_organization.
  helper_method :current_organization.

• Use self commenting code. Use before ‘some_explicit_method_name’ instead of a before_create method. An example of transforming some code where the intend was not explicit into the following code using before_create.

class Expense < ActiveRecord::Base
  before_create :mate_created_now_if_created_today
  
  protected 

  def mate_created_now_if_created_today
    if self.created_at Time.now.beginning_of_day
    self.create_at = Time.now
    end
  end
end

• Associations.

@john.documents #use this
Document.find_all_by_user_id(@john.id) # instead of  this
 
@john.documents.find(:all, :conditions=>["title like ?" "%koz%"] # use this
Document.find(:all, ...) # instead of 

#This becomes even easier to read when the search conditions become more elaborate, 
#i.e. Find all documents by john tagged with 'cool'? 
#This should be coded as 
cool.documents.find_by_user_id(@john.id)  
Document.find(:all, ...) #instead of using with now much more conditions . 

#Even better add a method explicating the association:  @john.docouments.taged_with(@cool) 
#or 
@cool.documents_authored_by(@john). 
#But just use one, don't repeat yourself. 
#You can get fancy you can use assosciation extensions: @john.documents.tagged_with(@cool). 

• Cargo-cult. Don’t just copy-paste the re-factoring you find on the RailsWay, try to understand the principles behind it. Make sure the concept applies to your code.

# Dont' use of !!
def account_code?
  !! @account_code.nil?
end

# use. More intention revealing
def account_code?
  @account_code ? true : false
end

• Share edit/new form. Don’t build the associations if required in the controller. Move it to a model class method.

 def self.build_with_associations
  returning new do |billable|
      blillable.booking = Book.build_with_assocations
   end
 end
 # some code omitted...man, the speakers are going to fast for my typing!

• Simplifying non restfull routes. Use map.with_options. Also format and indent nicely your routes.

Now onto some QA.

Q: Is the code from the code gonna be posted?
A: Yes, on the website.

Q: In the Account code example, could you use @account_code.
A: That would test something different as an empty string would return true. It depends on the requirement.

Q: Guidelines or best practices for overriding to_param?
A: If you want prettier Urls you can provide a to_param. Otherwise don’t bother.

Q: returning?
A: returning passes an object to a block and returns the object.

Q: Cascading validations?
A: Validations can be tricky in that case. They don’t have a best practices to present on that right at this moment. But don’t worry about that too much.

Q: Koz. Can you clarify what’s the context key is (in the routes)?
A: Forces a params[:context] = “www”

Q: How long does it take to do a typical RailsWay articles
A: 1 day or 2. But it depends.

Q: has_many : through. What about multiple : through? I.e. A through B through C through D?
A: I.e. A give me all yours Ds? If you really need it…add a custom method to the top.

Q: Attributes on join tables and conditions? Multiple associations? I.e has_many and has_one_current (through)
A: I.e. document has_many versions, current_version. Implementation doesn’t really matter, but if current_version has business meaning make it an explicit method.

Q: What is your advice on keeping a database column private? I.e. a Model cannot access a column.
A: We don’t see much value in that. Document this to not “touch” this. But try to find a solution. This can be difficult has private methods can be circumvented by send. Just make it explicit.

Q: Final words of wisdom?
A: The RailsWay has been a little quiet, but now that the conference has been wrapping up, we will dive back into it.

Q: How do you answer questions that relate to deprecated features?
A: We try to keep it to Rails 1.2.

JRuby on Rails: A Taste of Honey (for the Enterprise)

by Charles Nutter and Thomas Enebo JRuby Core Developer, Sun Microsystems.

Enterprise can be “doing cool new things and cool new ways”.

• The talk will cover
  • JRuby 101
  • Justifications
  • JRuby on Rails
  • Deployment Options
  • Migrations
• They are Java developers (10+ year)
• Working to build out JVM dynlang support
  *JRuby 101. JRuby is:
  • Ruby (1.8ish)
  • A non-Java language for the Java platform
  • A new way to look at Ruby and the JVM
  • Helping to expand Ruby’s reach
  • Helping the world better unstand Ruby
  • Really Cool
• JRuby is NOT:
  • An attempts to pollute or fork Ruby
  • An admission that Java sucks
  • The answer to every problem with Ruby
  • An attempt to alter Ruby or add incompatible features
  • Slow
• But it’s Java, Too

  include Java
  import java.lang.ArrayList
  list = ArrayList.new

• The rest you know
  • Obvious libraries pre-installed: Rubygems, Rake, Rspect
  • Mongrel supports JRuby (no remote gem)
  • Rails “just works”. Major orgs now investing in JRuby on Rails. Some folks where wondering if they “just” spawn a Ruby process.
• Justification or “Why would you do such a thing?”
  • Supporting the Status Quo (JRuby supports’ Ruby 1.8’s String)
  • Supports ActiveSupport::MultiByte
  • Exposing Java Unicode
  • Ruby 2.0 String on the way…
• Threading
  • JRuby supports Ruby’s Thread API
  • JVMs are native-threaded (uses multiple cores)
  • JRuby Supports thread pooling
• JRuby on Rails the basics
  • Many gems just work
  • Rails commands just work. rails myapp, rake db:migreate
  • jruby script/server #==> WEBBrick
• Some differences
  • MySQL driver works.
  • JDBC…different and faster. (database.yml needs url: and driver: com.mysql.jdbc.Driver)
  • JNDI for connection pooling (jndi: java:comp/env/jdbc/MyAppPool)
  • Broad database support (DB2, Derby, HSQLDB, JavaDB, MS Access, Mimer SQL, MySQL, PostgreSQL,…and many more)
  • ActiveRecord-JDBC: as no schema management API. MySQL pass 100% of tests, Derby and PostgreSQL have 17 failing tests out of 1000+ tests. Others at varying levels, but coming along. Oracle supports started recently and has less than 100 failed tests for now.
• Differentiation
  • No Native Extensions. Require ports. Mongrel done, Hpricot done, RMagick in progress. We’re looking for porters and recommendations
  • Command-line Performance. Java is not slow…except at startup. It’s an issue for now. Don’t expect stella CLI performance.
• Demo
  • Building, running, and deploying a JRuby on Rails application

  tar xzf jruby.tar.gz
  jruby_env
  jruby -v
  jruby -S gem rails -y
  jruby -S gem install gem_plugin
  jruby -S gem install mongrel
  jruby -S gem install activerecord-jdbc -y
  cp lib/mysql.jar jruby/lib
  jruby script/server
  http://localhost:3000
  envirvonment.rb 
    if RUBY_PLATFORM =! /java/
      require 'jdbc_driver' #I missed the proper code!
    end
  jruby script/generate migration entry
  jruby -S rake db:migrate
  # they continue to use the Rails generators and add standard Rails code

   cp -rp ../goldspike vendor/plugins
   jruby -S rake war:standalone:create
  # Assemble a .war file that deploys your Rails application as a standard J2EE application.
  http://localhost:8080/buggy/entries/list # Rails via J2EE

• Thanks You..but there is more.
  • There is a new option.
  • jruby -S gem install GlassFish-10.0.0.0-java.gem —no-wrappers
  • glashfish command. Command line to start J2EE server.
• Migration
  • It can be done!
  • MySQL: works, Dearby/JavaDB: nearly 100%, others…depends.
  • Fixtures: Usually bugs are YAML rather than DB
  • Options: 1) use something else,. 2) Use an equivalent Java library 3) Port the library… 4)5)6) # I missed these
• Deployment
  • Mongrel
  • More common approach is .war file
  • A Grizzly/GlassFish v3 option.
• Demo: Calling Java libraries from JRuby