RailsConf 2007 - Day 4
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
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.
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
# 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
Daniel Wanja
HTML5, iOS and Ruby On Rails Nouvelles Solutions, Inc.
d@n-so.com
