Wednesday, November 29, 2006

Email validation plugin

1.Setup the Rails project in Subversion by following the Subversion Primer for Rails blog post.
2. Ran into problems while installing plugins and after reading the James Adams's plugin book, I found the solution, I had to do:

script/plugin install –o

to install the plugin.

I also looked at the test directory of the plugin and did the same assert in my unit test.

Tuesday, November 21, 2006

Restarting WEBrick using script

pid=$(ps -o pid,command | grep '\' | awk '{print $1}')
kill -9 $pid
ruby script/server

This script restarts the Webrick cleanly (doing CTRL+c does not seem to shutdown the server)

Save it in a file, Do a chmod +x and type the command: sh to run it.

Thursday, November 09, 2006

Rake Aborted! Migration Headache

If the migration is not working in AWDWR Rails examples. Remember that you must be on Edge Rails to make it work.

The Ruby Way, Ruby in a Nutshell and Rails Plugin Extending Rails Beyond the Core

The Ruby Way and Ruby in a Nutshell books arrived from Amazon today. I will post the review when I get a chance.

I also bought the "short cut" Rails Plugins by Addison Wesley, a 100 page pdf book. This book is a gem. More to come soon...

Ruby Interceptor

Beyond Java book had a good example of Interceptor in Ruby. It is like AOP, but is simpler.

1. Create an alias for the method that you want to intercept.
2. Define a new method with the same name as the old method
3. Delegate the call to the old method and add new code to do whatever you want in this method.

You basically open the class, intercept the calls to that method and add additional functionality to the method.

Tuesday, November 07, 2006

Head Rush AJAX

Very good book. Shows the big picture in a very easy to understand way. The concepts are well explained and brings any novice up to speed quickly. This book helped me to move on to study other materials like RJS Templates by OReilly.

Metaprogramming with Ruby

Ruby is a dynamic language. You can create classes and methods at runtime. This is metaprogramming. You can write code that writes code.

Example: Data format driving the code, CSV file with header at the top.

file: people.txt
"Smith, John", 35, 175, "5'10"
"Ford, Anne", 49, 142, "5'4"
"Taylor, Burt", 55, 173, "5'10"
"Zubrin, Candace", 23, 133, "5'6"

1. The code must not change when a new attribute is added to the existing file or if we are given a different file with different attribute names.
2. The header values such as name and age must be treated as attribute names.

Create a class with a name derived from the file name. First line of the file must have list of attribute names. Checks that can added are: Check the attribute name is a legal Ruby method name, badly formed and missing data.

Given the file name we can create a class from its contents. So:

class_name = File.basename(file_name,".txt").capitalize # Create the class name
# e.g. "foo.txt" => "Foo"
klass = Object.const_set(class_name,

Monday, November 06, 2006


Awesome Firefox extension, install the plugin and browse the scripts. I installed a script that blocks all Yahoo ads. No more annoying flashing ads in my email account. There are tons of useful scripts. One of the script I installed compares the price of Amazon books with other online stores.

Also, install the scripts one at a time. Install a script and use your browser for sometime and see if everything is fine. This is important because I installed lot of scripts on my laptop and now one of the script is opening up all the links in a new window!

If you install it one at a time, you can easily find out which script is causing the problem.

Metaprogramming - Write code that generates code


1. Open-Closed principle - Programs that need to pre-generate data tables
2. Mini-language to handle boilerplate code - Programs that have a lot of boilerplate code that cannot be abstracted into functions
3. Programs using techniques that are overly verbose in the language you are writing them in

The art of metaprogramming, Part 1: Introduction to metaprogramming - Jonathan Bartlett

Excellent article on Metaprogramming with Ruby

Sunday, November 05, 2006

How to load fixtures after tables and indexes are created.

Steve Hammond's Blog had this interesting tip:

Can we tell a migration to load the fixtures after it has created the tables and indexes?

Fixtures.create_fixtures('test/fixtures', %w{archetypes tile_types tiles})

The first argument is the directory where the fixtures can be found and the second is an array of fixtures to be loaded. This will load the fixtures into the environment where the fixture is being run. As usual Rails will figure out YAML vs. csv fixtures for you

Thursday, November 02, 2006

Using the Ruby Development Tools plug-in for Eclipse

This plugin allows debugging, check it out.

Resources - Domain Specific Languages in Ruby

1. Seeing MetaClasses Clearly

2. MetaprogrammingWriterTopia by Bill Katz

3. Domain Languages as Rails Plug-Ins: Steve Hammond

4. Meta Rails - Stuart Halloway

5. Neal Ford - Language Oriented Programming Keynote

Script to Setup Rails in Subversion

The following notes is based on the thread Create a rails project skeleton and import and checkout from svn all at once!

1. Create your repository on the server

2. Put the source code in a file called ‘svnrails’ inside of a directory that’s in $PATH. I have mine in /usr/local/bin (where the svn, rails and ruby binaries like to do their thing)

3. This will work with any kind of svn repository (ie. file:///, svn://, http://)

4. If your repository requires authorization, you will be prompted when necessary.

5. I haven’t built any error handling into this, so use the ol’ “measure twice and cut once” technique when typing this command

6. Type the command without arguments for usage

7. You have the option of not creating the /trunk, etc. directories in the repository; and the default command looks like this:

svnrails myapp svn://myserver

8. As long as you’ve created a repository called myapp on the subversion server, this script will automatically import your project into it. In other words, it defaults the name of the repository to be the same as the name of the app; this can be overriden (sensible defaults and all that).

9. Ignores various files in the repository as per the rails wiki

You can find the code here

Doubt: Does this require any changes for Edge Rails?

Wednesday, November 01, 2006

ZenTest Notes

To use unit_diff, pipe normal tests through it:

$ ruby ./TestZenTest.rb | unit_diff


pressing Ctrl-c once reruns the tests immediately. Pressing the key combination twice terminates autotest.

$ autotest -help


-v Be verbose.
Prints files that autotest doesn't know how to map to tests.

-rails Force rails mode.
Rails will be automatically detected by the presence of config/environment.rb. Use this if you don't have one.

You may need to run 'rake db:test:prepare' before
starting autotest on a rails project.

-vcs=NAME Version control system to update.
Autotest will automatically update every vcstime
Autotest understands Perforce (p4), CVS (cvs) and
Subversion (svn).

-vcstime=N Update source control every N seconds.
Defaults to every five minutes (300 seconds).

ZenTest MyProject.rb TestMyProject.rb > missing.rb

./TestMyProject.rb | unit_diff


multiruby ./TestMyProject.rb

(and other stuff for Test::Rails)

How to use ZenTest on Rails?

ZenTest Documentation

Resources for Testing Ruby on Rails

1. A Guide to Testing the Rails
2. Test First Programming with Ruby
3. Ruby on Rails Testing Cheat Sheet
4. Testing Rails Apps - Mike Clark
5. Test Your Helpers
6. Testing Rails controllers communicating with external web services
7. Test Driven Designg Using ZenTest
8. A Rails Testing Tutorial
9. How to Use ZenTest with Ruby
10. Autotest Rails
11. Testing Rails Apps
12. Selenium on Rails
13. Running Your Rails App Headless
14. YAML Fixtures
15. Testing RJS Templates
16. RJS Assertions
17. 2005 Rubyconf ZenTest Movies - Ryan Davis
18. ZenTest Blog
19. Test-First development