OnRails.org: Category Ruby On Rails

MWRC 2010 - Day 1 Live Video

Daniel Wanja — Thu, 11 Mar 2010 15:53:46 +0000

The conference is about to start in 30 minutes, the room starts to buzz. The confreaks guys have their camera and video recording equipment all setup. So you will be able to catch up the conference online soon. Somehow I really like single track conferences and the sessions seem really great and will be fast passed, 30 to 45 minutes. Check out the schedule. So I will sit back and enjoy the show.

Follow it live on Justin TV!!

Watch live video from Mountain West Ruby Conference on Justin.tv

Salt Lake City is definitively a beautiful city, surrounded by it’s mountains…

Rails 3: Rack Middleware

Daniel Wanja — Thu, 18 Feb 2010 19:14:00 +0000

I’m watching the Rails Online Conference, February 2010 Exploring Rails 3 and really like how they setup the rack middleware.

...From the slides.

Rack Middleware

http://github.com/rack/rack/tree/master/lib/rack

Content Modifying

Rack::Chunked
Rack::ContentLength
Rack::ConditionalGet
Rack::ContentType
Rack::Deflater
Rack::ETag
Rack::Head
Rack::MethodOverride
Rack::Runtime
Rack::Sendfile
Rack::ShowStatus

Behavioral

Rack::CommonLogger
Rack::Lint
Rack::Lock
Rack::Reloader

Routing

Rack::Cascade
Rack::Recursive
Rack::Static
Rack::URLMap

Rack::Contrib

http://github.com/rack/rack-contrib

Rack::AcceptFormat
Rack::Access
Rack::Backstage
Rack::Callbacks
Rack::Config
Rack::Cookies
Rack::CSSHTTPRequest
Rack::Deflect
Rack::Evil
Rack::HostMeta
Rack::JSONP
Rack::LighttpdScriptNameFix
Rack::Locale
Rack::MailExceptions
Rack::NestedParams
Rack::NotFound
Rack::ProcTitle
Rack::Profiler
Rack::ResponseCache
Rack::ResponseHeaders
Rack::RelativeRedirect
Rack::Signals
Rack::SimpleEndpoint
Rack::TimeZone

Coderack.org

Check also out http://coderack.org ...99 pieces of Rack Middleware

RailsGuide: Rails On Rack

http://guides.rubyonrails.org/rails_on_rack.html

Time.onrails.org is closing!

Daniel Wanja — Thu, 18 Feb 2010 03:15:03 +0000

I just send an email to thousands of users to notify them that time.onrails.org is closing down. I don’t think many of these users are active but just in case I wanted everyone to be able to get their data out of the system if so they wished.

I will turn down the service on March 17th at 9pm.

Now why in the hell would I close this service. In brief I created it for myself on the plane to RubyConf 2005, thought it was cool and opened it to the public in April 2006. I haven’t updated the code much since many years and just don’t have the time to add new features, and trust me Rails code from 2005 looks slightly different than nowadays Rails code.

For posterity here is the “official” announcement blog entry of the creation of the service:

April 13, 2006 – LAUNCH time.onrails.org, time tracking made simple!

And here are few more articles related to time.onrails.org.

Here is part of the email I send to the users:

Time.onrails.org is closing down March 17th 2010 at 9pm Mountain time.

You can export your time entry for each project by clicking on the export buttons at the bottom of each project page or you can export your full account by just login and then go to this url:

http://time.onrails.org/export/xml/user

This will export each of the projects will all sections including the notes.

Please start transitioning to a new service now.

As a replacement service I would suggest harvest (http://www.getharvest.com/) which offers a free plan which allows for 2 projects, 4 clients, unlimited invoicing for 1 user absolutely FREE.

Thank you to all the users over the years I hope you enjoyed this free service. Time.onrails.org enjoyed thousands of users and I received many nice complimenting emails for the service over the years. The main reason that I close this service is that I am starting to use harvestapp for my own time tracking. I wrote time.onrails.org back in 2005 just for fun and thought it could be useful to others. It fulfilled my needs of keeping track of time for the various customer projects I worked on over the last few years.

Since we moved to slicehost it was very stable and I just have good things to say about slicehost, they are just great. Recently one of the slice time.onrails.org was running on had issues and got moved twice over two days. Again slicehost was on top of that situation and I just sat back and they did all the work. But this also reminded me that I cannot just keep the service running without giving it the time and effort it deserves and just now I don’t have that time as I am working on other projects, such as http://appsden.com.

So I went on the search for a replacement service and looked at many out there. And Harvest just added the timestamp feature, which is exactly how I track time, their app is more fleshed out than time.onrails.org, so I decided to move over to use their services.

The great news is while I tweeted about my move to Harvest, Doug, which I knew from his time in Denver mentioned that he now works for Harvest. So he put me in contact with the cofounder and I asked him if they could get some deal for my current users, and they where very responsive and create a special promo code. Thanks for that and I hope you try and enjoy their services. Just for disclaimer I didn’t ask for any monetization or anything for referring you to Harvest, the idea was just to have an alternate offering in case you needed one. But they offered me a free Solo plan, so hey, at least I got that out of this whole ordeal.

Please don’t hesitate to contact me for any question at daniel@onrails.org.

Thank you again for having tried out or being a user of time.onrails.org over all these years.

Kind regards, Daniel Wanja

Amazon RDS: Amazon Relational Database Service or MySQL in the Cloud for Ruby On Rails.

Daniel Wanja — Thu, 29 Oct 2009 03:02:27 +0000

For watchthatsite.com (not public yet) I have an instance on EC2 with Rails and MySQL but was looking for a more solid hosting solution for MySQL. And how fortunate, Amazon came out with the solution I need this week. Basically with two command line instructions you can start a new server with mysql configured, tuned, and secured. In this blog entry I will go through the steps that perform to move my sql database to Amazon RDS.

You can find more information on Amazon Relational Database Service (API Version 2009-10-16) here.

Prerequisite: you need to signup for an account on aws.amazon.com, it can be used for EC2, S3, SimpleDb and all the other services AWS provides.

1) Install the Command Line Toolkit

First thing, go download the command line toolkit and read the README.TXT on how to install it. In short you unzip the files, I did put mine at /Developer/aws/RDSCli-1.0.001. Then you create a credential file which contains your AWS access key id and secret key. Then I configured my ~/.bash_profile as follows:

export AWS_RDS_HOME=/Developer/aws/RDSCli-1.0.001
export AWS_CREDENTIAL_FILE=$AWS_RDS_HOME/credential-file-path.conf
export JAVA_HOME=/Library/Java/Home
export PATH=$AWS_RDS_HOME/bin:$PATH

to see that the command line toolkit is setup correctly type $rds—help

You will need the command line tool to execute several commands described here after.

2) Create an Instance

Let’s create a MySQL Server instance. RDS offers the following 5 server instance classes:

db.m1.small (1.7 GB of RAM, $0.11 per hour)
db.m1.large (7.5 GB of RAM, $0.44 per hour)
db.m1.xlarge (15 GB of RAM, $0.88 per hour)
db.m2.2xlarge (34 GB of RAM, $1.55 per hour)
db.m2.4xlarge (68 GB of RAM, $3.10 per hour)

I will choose a small instance which I will call dbserver1 with a database name db1 and allocate 5g of database space. I also set the master username as admin and password as secret.

$ rds-create-db-instance --db-instance-identifier db1 --allocated-storage 5 --db-instance-class db.m1.small --engine MySQL5.1 --master-username admin --master-user-password secret --db-name db1 --headers

The output is the following:

DBINSTANCE  DBInstanceId  Class        Engine    Storage  Master Username  Status    Backup Retention
DBINSTANCE  db1           db.m1.small  mysql5.1  5        admin            creating  1               
      SECGROUP  Name     Status
      SECGROUP  default  active
      PARAMGRP  Group Name        Apply Status
      PARAMGRP  default.mysql5.1  in-sync

Now you have a server running and you are being billed $0.11 per hour, that’s like $80 a month without bandwidth but with backup…and it took only 2 minutes to get going. Can’t beat that.

To see all the instances you have you can issue the

rds-describe-db-instances --headers

3) Grant Network Access

So I will grant access from my notebook, assuming the ip address is 24.19.0.48 (you can also specify ranges i.e. 24.19.0.0/50). (Note that access was revoked by AWS, not sure why??)

rds-authorize-db-security-group-ingress default --cidr-ip 24.19.0.48 --headers

I also have an ec2 instance which I want to grant access to

rds-authorize-db-security-group-ingress default --ec2-security-group-name watchthatsite --ec2-security-group-owner-id 526541544691

Note the ec2-security-group-owner-id is your Amazon AWS account number, you can find it for example on you account activity page. To see your security configuration issue the following command: rds-describe-db-security-groups default—headers

4) Using the Database

To use your database you first need to find out the endpoint address of your new server. So describe you instances:

rds-describe-db-instances --headers command

DBINSTANCE  DBInstanceId  Created                   Class        Engine    Storage  Master Username  Status     Endpoint Address                              Port  AZ          Backup Retention
DBINSTANCE  db1           2009-10-28T22:53:31.666Z  db.m1.small  mysql5.1  5        admin            available  db1.cyhik6zpub5c.us-east-1.rds.amazonaws.com  3306  us-east-1b  1               
      SECGROUP  Name     Status
      SECGROUP  default  active
      PARAMGRP  Group Name        Apply Status
      PARAMGRP  default.mysql5.1  in-sync

You find out your endpoint address, for me db1.cyhik6zpub5c.us-east-1.rds.amazonaws.com

So now you can connect to your database:

mysql -h db1.cyhik6zpub5c.us-east-1.rds.amazonaws.com -P 3306 -u admin -p db1

Let’s configure my Rails application to point to that database and run a migration:

So I change my config/database.yml to point to the above database

development:
    adapter: mysql
    host: db1.cyhik6zpub5c.us-east-1.rds.amazonaws.com
    reconnect: false
    database: db1
    username: admin
    password: secret

 rake db:migrate

Wow, seem to work.

Let connect to the mysql console and do a show tables;

+-------------------+
| Tables_in_db1     |
+-------------------+
| schema_migrations | 
| users             | 
| watches           | 
+-------------------+

Yep, all there.

Now I still have to move my old production database to the new one, so let’s dump the data from my old database:

mysqldump watchthatsite_development -u admin > wts.sql

and reload that data in the new database:

mysql -h db1.cyhik6zpub5c.us-east-1.rds.amazonaws.com -P 3306 -u admin -p db1 < wts.sql

Restarting my Rails server…That’s all!

Enjoy, Daniel.

RMagick (from source) on Snow Leopard

Solomon White — Fri, 04 Sep 2009 00:31:00 +0000

After the release of 10.5, I published an article about building RMagick from source on Leopard. I won’t rehash the why, you can read the original article for that. My clean install necessitated updating the RMagick script, so here’s what worked for me to install from source on Snow Leopard! For the impatient, here’s the download link: rmagick-build.sh

First, we start with installing wget, as it seems to be a bit more clever than curl about dealing with mirrors, etc. Then, we compile and install each prerequisite package. Finally, we install the gem.

All the links in the script worked for me, but, depending on your location, network, conditions, etc, your mileage may vary. Enjoy!

#!/bin/sh

# install wget, which is cleverer than curl
curl -O http://ftp.gnu.org/gnu/wget/wget-1.11.tar.gz
tar zxvf wget-1.11.tar.gz 
cd wget-1.11
./configure --prefix=/usr/local
make
sudo make install
cd /usr/local/src

# prerequisite packages
wget http://nongnu.askapache.com/freetype/freetype-2.3.9.tar.gz
tar zxvf freetype-2.3.9.tar.gz
cd freetype-2.3.9
./configure --prefix=/usr/local
make
sudo make install
cd /usr/local/src

wget http://superb-west.dl.sourceforge.net/sourceforge/libpng/libpng-1.2.39.tar.gz
tar zxvf libpng-1.2.39.tar.gz
cd libpng-1.2.39
./configure --prefix=/usr/local
make
sudo make install
cd /usr/local/src

wget ftp://ftp.uu.net/graphics/jpeg/jpegsrc.v6b.tar.gz
tar xzvf jpegsrc.v6b.tar.gz
cd jpeg-6b
ln -s `which glibtool` ./libtool
export MACOSX_DEPLOYMENT_TARGET=10.6
./configure --enable-shared --prefix=/usr/local
make
sudo make install
cd /usr/local/src

wget ftp://ftp.remotesensing.org/libtiff/tiff-3.9.1.tar.gz
tar xzvf tiff-3.9.1.tar.gz
cd tiff-3.9.1
./configure --prefix=/usr/local
make
sudo make install
cd /usr/local/src

wget http://superb-west.dl.sourceforge.net/sourceforge/wvware/libwmf-0.2.8.4.tar.gz
tar xzvf libwmf-0.2.8.4.tar.gz
cd libwmf-0.2.8.4
make clean
./configure
make
sudo make install
cd /usr/local/src

wget http://www.littlecms.com/lcms-1.17.tar.gz
tar xzvf lcms-1.17.tar.gz
cd lcms-1.17
make clean
./configure
make
sudo make install
cd /usr/local/src

wget ftp://mirror.cs.wisc.edu/pub/mirrors/ghost/GPL/gs870/ghostscript-8.70.tar.gz
tar zxvf ghostscript-8.70.tar.gz
cd ghostscript-8.70
./configure  --prefix=/usr/local
make
sudo make install
cd /usr/local/src

wget ftp://mirror.cs.wisc.edu/pub/mirrors/ghost/GPL/gs860/ghostscript-fonts-std-8.11.tar.gz
tar zxvf ghostscript-fonts-std-8.11.tar.gz
sudo mv fonts /usr/local/share/ghostscript

# Image Magick
wget ftp://ftp.fifi.org/pub/ImageMagick/ImageMagick.tar.gz
tar xzvf ImageMagick.tar.gz
cd `ls | grep ImageMagick-`
export CPPFLAGS=-I/usr/local/include
export LDFLAGS=-L/usr/local/lib
./configure --prefix=/usr/local --disable-static --with-modules --without-perl --without-magick-plus-plus --with-quantum-depth=8 --with-gs-font-dir=/usr/local/share/ghostscript/fonts --disable-openmp
make
sudo make install
cd /usr/local/src

# RMagick
sudo gem install rmagick

UPDATE There is a bug with libgomp that breaks the convert utility (See comments below). the --disable-openmp configure option has been added to the script to fix this.

UPDATE 2 A new patchlevel of ImageMagick has been released that supersedes the original one referenced in this script, and the original has been removed from the server. Thanks to Sebastian for this update that will grab the latest release.

Introducing Hashdown

Solomon White — Tue, 04 Aug 2009 23:51:00 +0000

If your database is normalized, you will almost always end up with small tables (often referred to as reference data or lookup tables) which provide a set of possible values for a particular attribute. (e.g. Currency, Category, etc.) A common pattern that emerges in many applications is accessing these records by a symbolic name (as opposed to by id) for purposes of clarity when reading the code. In C (and friends), the database ids can be mapped to the positions of an enum datatype. I recently released the hashdown plugin that provides hash-like access for reference data records, and also adds some dropdown option list generation support, since this data is often used to populate select list in forms.

As an example of what hashdown does, suppose we have the following model:

class CardType < ActiveRecord::Base
end

with the following data:

+----+-------+------------------+
| id | code  | name             |
+====+=======+==================+
| 1  | visa  | Visa             |
| 2  | mc    | MasterCard       |
| 3  | disc  | Discover         |
| 4  | amex  | American Express |
+----+-------+------------------+

By adding the following line to the model:

class CardType < ActiveRecord::Base
  finder :code
end

You get the functionality of a hash-like square-bracket accessor for the model that will let you do something like:

@order.card_type = CardType[:visa]

The underlying implementation is similar to:

def CardType < ActiveRecord::Base
  def self.[](value)
    find_by_code(value)
  end
end

...except it adds a caching layer to boost performance by preventing repeated database access.

Adding the following directive:

def CardType < ActiveRecord::Base
  selectable
end

to the model gives you a class method called select_options that can be used to populate a select list like this:

<%= form.select :card_type_id, CardType.select_options %>

produces:

<input type="select" name="order[card_type_id]" id="order_card_type_id">
  <option value="1">Visa</option>
  <option value="2">MasterCard</option>
  <option value="3">Discover</option>
  <option value="4">American Express</option>
</input>

By default, this will use the id attribute as the submitted value of the option and call a display_name method (if it exists) for the displayed value of the option, falling back to the name method/attribute. Each of these can be overridden by passing a symbol attribute / method name, or a lambda that will be executed to generate the value. For (a contrived) example:

<%= form.select :card_type_id, CardType.select_options(:key => :code, :value => lambda{|card_type| card_type.name.reverse }) %>

produces:

<input type="select" name="order[card_type_id]" id="order_card_type_id">
  <option value="visa">asiV</option>
  <option value="mc">draCretsaM</option>
  <option value="disc">revocsiD</option>
  <option value="amex">sserpxE naciremA</option>
</input>

Again, the select_option results are cached for better performance.

This is a pretty small plugin that I’m using to DRY up some code in a current project I’m working on. Let me know if you have feature requests (or fork and patch it on GitHub!)

Behind the scene: Quiltivate.com a beautiful Flex on Rails website.

Daniel Wanja — Thu, 16 Jul 2009 04:20:01 +0000

I met Phil several years ago at Derailed, the (Denver Ruby on Rails user group, and for a long time he was curious about how Flex can be integrated with Rails, about the graphical possibilities that Flex offers, the advantages over plain HTML/CSS/Javascript. Then he told me Kacie, his wife, had an idea about a website. She is passionate about quilts and has an eye for details and excellence. Phil is a geek that loves Rails, Kacie loves quilts, it's like Quilting meets Web 2.0 and quiltivate.com was born. In fact Phil and Kacie hired me to create a Quilt Builder that integrates with Quiltivate.com. Kacie had the vision for the whole concept, a simple to use quilt builder that removes lots of the hassle of calculating how much fabric of what color is needed and allows to play with blocks, shapes and colors. She drew a paper prototype that really highlights the tag line of their site" Innovating Traditional Quilting". Quiltivate.com offer much more than a Quilt Builder, it's a blog and a community centered around the art and craft of quilting. Over the last year I spent a couple of hours here and there, well a little more than that, to transform the paper prototype into a real Flex application. Rather than writing about what the tool does and how it does it, let's have a little look at behind the scene of the Quilt Builder with this video:

Behind the scene: Quiltivate.com a beautiful Flex on Rails website. from daniel wanja.

Check out quiltivate.com for a video on how to really use the Quilt Builder and go try it out. As it's fresh out of the gates their may be a little quirks here and there, so please let me know what you find. So thank you Kacie and Phil for getting me on this project, it was really fun! Enjoy, Daniel.

Screencast: Testing Flex Apps with Cucumber - Take 2

Daniel Wanja — Mon, 13 Jul 2009 17:04:11 +0000

I was not really happy with last week's screencast I did on testing Flex with Cucumber. Effectively doing screencast is not an easy endeavor and trying to it myself is making me appreciate all the other screencast I watch so much more. So last week I just wasn't comfortable while I recorded it, not sure why, but I thought I should try to capture it again. And the second time around I felt better, maybe I should alway take two takes (or even more :-). So here is the new one...

Screencast: Testing Flex Apps with Cucumber - Take 2 from daniel wanja.
To run this code you need to have all the gems installed. So config your Rails to run Cucumber with FunFx (in config/environments/test.rb):

config.gem "rspec", :lib => false, :version => ">= 1.2.7"
config.gem "rspec-rails", :lib => false, :version => ">= 1.2.7"
config.gem "webrat", :lib => false, :version => ">= 0.4.4"
config.gem "cucumber", :lib => false
config.gem "funfx"
config.gem "safariwatir"

Config Cucumber to have @flex available (in features/support/env.rb)

require 'funfx'
require 'funfx/browser/safariwatir'

browser = Watir::Safari.new
browser.goto("http://localhost:3000")

Before do
  @flex = browser.flex_app('flashContent', 'flashContent')
end

at_exit do
  browser.close
end

In the same file disable transactional fixtures

Cucumber::Rails.use_transactional_fixtures

Ensure that your Flex application is compiled with the funfx library and the automation library linked in.

<flex-config>
  <compiler>
	<include-libraries append="true">
		<library>../../lib/funfx-0.2.2.swc</library>
		<library>../../lib/automation.swc</library>
		<library>../../lib/automation_agent.swc</library>
		<library>../../lib/automation_dmv.swc</library>
		<library>../../lib/automation_agent_rb.swc</library>
	</include-libraries>
  </compiler>
</flex-config>

Screencast: Testing Flex Apps with Cucumber

Daniel Wanja — Wed, 08 Jul 2009 07:03:00 +0000

I was playing with Cucumber and FunFx to drive a Flex application and it's really cool and created this screencast to show how this all works together. The first 5 minutes I build a Restfulx scaffolded Flex application. The following 5 minutes I configure the Flex app with FunFx, which is required to be able to drive the app from Cucumber. Then the main part which is 20 minutes of creating three cucumber scenarios that drives the Flex application. Check it out:

Testing Flex Apps with Cucumber from daniel wanja The source code can be found on github Enjoy! Daniel
UPDATE: An updated version (and slightly) different version of the screencast can be found here.

RailsConf 2009 Day Two

Solomon White — Thu, 07 May 2009 03:13:00 +0000

Day Two got off to a good start. Engine Yard did a promotional pitch—the speakers could have been a bit more polished, but it was interesting stuff about their one-button-deployment, and overall not bad for an advertisement.

Next up was Chris Wanstrath. He started with a lead in regarding how to become a famous Rails developer—focusing on yourself, your blog readership numbers, your twitter follower count, etc. Later, he talked about how he went from being an unemployed college dropout to co-founder of the very successful GitHub, due to sharing code. His point was that in his eyes, it’s better to focus more on the community: share code, contribute to open source projects, even write documentation for existing projects. Being a good developer trumps being a famous developer. The complete text of the talk is online here .

For the first session of the day, it was a tough call between Rack/Sinatra and Metric Fu. I finally went with:

Using metric_fu to Make Your Rails Code Better – Jake Scruggs

The central theme of this talk was how to use automated code analysis to direct you on where to spend your refactoring cycles. He used Carlin’s law (Anyone going slower than me is stupid; anyone going faster than me is crazy), but applied to programming. As your programming skills change over time, you see the same code differently.

He touched on coverage as a baseline that you should be doing as a part of your code analysis, then went on to complexity analysis, reviewing two tools available to analyze the “complexity” of your code: Flog and Saikuro. Flog examines your code (flog -g app for a Rails app) and gives you a (somewhat arbitrary) numeric range measuring the relative complexity of your code. Basically, 0-10 is awesome (and practically unatainable), 11-20 is okay for real world methods, and it goes downhill from there. If you have 200+ complexity scores, refactor immediately! Flog is somewhat opinionated about what is good/bad or more/less complex, but generally does a good job in helping you avoid the “icebergs”.

Saikuro gives a more concrete result—the “score” is the number of branches through a method, including tertiary operators, foo if/unless bar, etc. This is a plus over Flog, and usually indicates about how many tests you should have (one per branch). The downside to Saikuro is that it does not pick up on dynamically defined methods, where Flog does.

Next, we walked through a refactoring example, where Jake showed using high Flog scores as a hit list of where to refactor next. He also mentioned that better readability trumps lower complexity scores, one thing to keep in mind—as being generated by automated tools, the scores should be taken as a guide, not a law. A good point was brought up during Q&A: there is currently no way to “flag” a high-scoring method as acceptable, so if you have a justifiably complex method that you choose to live with (e.g. for readability), then you’ll have to live with the flogging you will receive. I’m sure patches would be welcome if someone wanted to fix this!

On to code smell and Reek and Roodi, tools to identify smells (overly large methods, etc.) Reek tends to warn over smaller issues than Roodi, and can indicate false positives. Roodi generally tends to have fewer complaints—if it warns about something, it should probably be fixed!

Next up was Flay, which detects non-DRY-ness in code, anything from strict copy-n-paste to functionally identical blocks with different variable names to do..end blocks matching curly-brace blocks.

Also covered was a way to track source control churn. At this point, you’re probably thinking “How can I keep up with all this?” Luckily, there’s metric_fu, a way to wrap all this up into one package and get all this code analysis goodness in your project. Install the gem, then run rake metrics:all. For more info, installation instructions, etc., see: http://metric-fu.rubyforge.org/ Looking forward to adding this bag of tricks to our CI toolset.

Rails 3: Step off of the Golden Path – Matt Aimonetti

Matt started off with a history of programming languages and how Ruby came to be, including some of Matz’ core philosophies embodied in the language. Moving along to Rails, he talked about the growth of Rails and the desire for increased performance and options that led to the split between Rails and Merb. This led us in to the discussion of the current and future state of affairs for Rails 3.

Currently, as DHH mentioned in the opening keynote, there is no official release for Rails 3. However, much work has been done, and a direction / ideas are emerging that will be implemented once an official release is ready. These include:

improved performance
increased modularity
agnosticism
public api
mountable apps

Matt emphasized that there will be no drastic changes, and by default, rails app will generate a very similar application to what you would get today under 2.x. However, there will no longer be the idea of “the one true Rails way” of building an app—the framework will be less opinionated. However, you should go through a process of justification to see if you really need something different than the default stack.

Some of the options you will be able to choose from:

JavaScript frameworks, including jQuery, YUI, ExtJS, MooTools, Prototype, or the ability to write your own, and plug it in.
Different templating engines: HAML, ERb (this is already doable in Rails)
Different ORMs: ActiveRecord, DataMapper, SEQUEL, Hibernate, non-RDBMS stores like CouchDB, Tokyo Cabinet, etc.

At this point, Matt gave a demo of some of the nicer features in DataMapper, contrasted with ActiveRecord:

DataMapper re-uses existing Ruby object for both sides of a has_many / belongs_to relationship. In other words, if I load parent and child records from the database, and look at parent.object_id as compared to child.parent.object_id, under DataMapper, these will point to the same object automatically, while with ActiveRecord, these will be separate objects. (Note that inverse_of was recently checked into rails, which enables this in ActiveRecord as well )
DataMapper does automatic lazy loading as well as strategic eager loading, so in this scenario:

@parent = Parent.find(12345)
@parent.children.each do |child|
  puts child.name
end

ActiveRecord would need some hints (:include => :children) to be added to the original query to avoid the N+1 iteration problem, where DataMapper is clever enough to figure that out and generate 2 SQL queries for you automatically.

The ability to have multiple repositories (which looks like it means databases), and a copy method on models to clone data from one database to another—one use case would be an automatic archive or backup process that copies data generated within the last week to a backup database.
Query Path, allowing more flexibility in SQL condition generation (WHERE name LIKE ‘foo‘)
one potential gotcha that was mentioned: DataMapper does not support STI and Polymorphic associations as well as ActiveRecord does

Finally, he highlighted some options that would be available for even further customization, such as defining your own:

file structure
router DSL
request handling But he voiced the opinion that the vast majority of Rails apps will not need anything like this—make sure your need justifies coloring outside the lines.

All in all a good presentation, maybe a bit much focus on DataMapper specifically. However, I personally enjoyed the DataMapper bits, and might have to try it out on a project, if it’s a fit.

Art of the Ruby Proxy for Scale, Performance, and Monitoring – Ilya Grigorik

I skipped out on the afternoon sessions, so my next talk was Ilya’s—never disappointing. Ilya spoke about EM-Proxy, his event machine based proxy. He gave good example code of how EM proxy could be used to implement transparent and intercepting proxies.

It started with an itch at PostRank, Ilya’s blog aggregation solution. An effective staging environment should closely resemble the production environment—the problem was that their production environment spanned nearly 80 (virtual) servers on EC2’s cloud. Spinning up that many servers just as a staging environment was an expensive proposition. Also, simulating production traffic then becomes a challenge, as you end up trying to store production logs and “replay” them into the staging environment. The way that they chose to solve the problem was to separate a group of the servers into a staging app server pool, set up a proxy that would transparently (to the end user) intercept incoming requests, send them to both the production and staging pools simultaneously, then return only the production response to the user, using the staging response internally for benchmarking, testing output, etc. With this strategy, the more static parts of the system (web servers, load balancers, etc.) can be shared across environments, and the staging environment is testing the part that actually changes (the application servers).

The first example code was a transparent proxy that simply forwarded a request from one port to another. Ilya built on this to show how you could dynamically alter request/response data on the fly. Finally, he built up to the original scenario: duplexing a single request across two (or multiple) backend servers, but returning only a specific response. As he mentioned in the talk, one strategy for servicing a specific request as fast as possible might be to send the request to all machines in your pool, then respond with whichever request completed first.

These examples were centered around HTTP requests, but he went on to show some other examples of how this is not protocol-specific: you are just dealing with data over a socket connection, so as long as you understand the underlying protocol, EM-Proxy could be useful. His examples showed SMTP proxies for accepting/rejecting incoming mail by email address and implementing a spam filter by forwarding the incoming mail to Defensio before passing it along to your real SMTP server. The final example was pretty clever: an implementation of EM-Proxy to reduce the memory overhead of beanstalkd by selectively delaying queue inserts based on the scheduled execution time—basically buffering far future jobs into the database instead of immediately inserting into the work queue.

Slides are available here: http://bit.ly/ruby-proxy

Another packed day at RailsConf 09, one more to go!