The Philanthropic Programmers

Posted by Mike Blake Tue, 22 May 2007 21:16:00 GMT

Something fantastic is happening in the Ruby and Rails World.

Do unto others

Open source developers know from experience that what goes around comes around. Contributions to projects like Rails invariably come back to benefit everyone, including the contributor. The community is now thinking on a larger scale. Frameworks come and go, but love is timeless .

The Summer of Love

Whytheluckystiff is focusing his power on Hackety Hack an amazing application that teaches children programming. And it’s likely more zeitgeist than coincidence that a professor from MIT, where the generous open source license originated, has started the noble project called One Laptop per Child . Developers everywhere like Amy Hoy are giving back in order to share the passion.

Chad Fowler has challenged the entire community to harness our newfound passion to do great things. And the community has only just begun to respond. During RailsConf over $33,000 was raised for charity.

Witness the Transformation

Software evolves rapidly. Humanity seems to evolve at a slower pace, but if you watch carefully, with ruby colored glasses , you can see it happening.

Posted in Create, Pray | Tags love, rails, ruby | no comments

Hibernate 3.x Migration Guide

Posted by Mike Blake Thu, 26 Apr 2007 11:30:00 GMT

Update 4/30

I finally did find the real Hibernate 3 Migration Guide. My fun with Hibernate is over though, I've found an easier persistence solution with the clients homegrown method. I believe every single java project I've worked on in the past 10 years has used a different and unique Persistence mechanism. My favorite was Francois' PersistentEntity at ViaFone.

[junit] (cfg.Configuration 1312) configuring from resource: /hibernate.cfg.xml

[junit] (cfg.Configuration 1289) Configuration resource: /hibernate.cfg.xml

[junit] (util.DTDEntityResolver 30 ) Don’t use old DTDs, read the Hibernate 3.x Migration Guide!

A quick search does not turn up a Hibernate Migration Guide, so I decided to create this one.

The Hibernate 3.x Migration Guide

1. Get Ruby

2. Install Rails

3. Rebuild your application.

4. Have fun again!

Posted in Create | Tags hibernate, migration, rails, ruby | no comments | no trackbacks

Testing a Non-Rails Application Using Rails

Posted by Mike Blake Sat, 31 Mar 2007 13:11:00 GMT

Rails developers working on enterprise software projects are suprised to discover the lack of automated tests in many mature web applications. As frustrating as this can be, A lack of automated tests is also a tremendous opportunity to

1. Learn your non-rails applications underlying database structure.
2. Demonstrate to a devlopment team the power of The Rails Framework.
3. Encourage automated testing.

Rails may be the quickest path to automate some basic test of your non-rails applications data model. These steps will get you all set up to write your automated tests in Ruby.

1. Connect to Your Enterprise Database
2. Set DB Conventions
3. Safety Net
4. Duplicate the Schema
5. Extract Development Data

I. Connect to Your Enterprise Database from Rails.

Download and install any os driver, ruby gems, and rails adapters needed to connect to your database:

Supported Rails Databases:

MySQL
DB2
Oracle
Sybase
SQLServer
PostgreSQL
Firebird

II. Set Your Existing Database Conventions

Rails Recipes , Recipie #16 can walk you through this very quickly.

Identify any conventions used by your legacy database. Application wide conventions can be set in the config/environment.rb file. They are specified by calling the appropriate class methods available on ActiveRecord::Base. The methods you need to call depend on how your database is configured:

ActiveRecord::Base.table_name_prefix 'myapp_'
ActiveRecord::Base.table_name_suffix = '_def'
ActiveRecord::Base.sequence_name = 'dev_company'
ActiveRecord::Base.pluralize_table_names = false 
ActiveRecord::Base.primary_key_prefix_type = :table_name_with_underscore # or :table_name

III. Safety Net

Load the SafetyNet Plugin into your rails app to prevent from destroying your development database.

IV. Duplicate Your Database Schema

OK , with your dev and test development databases set correctly, let’s try duplicting the schema.

rake db:test:clone

If this works right off the bat, you’re one of the lucky ones. Skip to Extracting Development Data

If you recieved errors from the clone command, do steps A through C .

A. You can now correct any errors you may have had by manually modifying schema.rb . See Oracle Errors for some problems I had with the Oracle Database. Since schema.rb is generated, it’s a good idea to rename it when you modify it manually.

B. The clone command above may have started loading data; you need may to purge the test db. rake db:test:purge

C. Tell rake to load your new schema file by passing the new name, relative to RAILS_ROOT in the SCHEMA environment variable:

rake db:schema:load RAILS_ENV=test SCHEMA=db/oracle_schema.rb

V. Extracting Development Data

Copy the code from Rails Recipe #42: extract_fixtures.rake to your RAILS_ROOT/lib/tasks directory.

TIP: If your develoment database has lots of data, Modify the SQL Select in this code to limit the amount of data you copy using the SQL limit statement:

sql = "SELECT * FROM %s limit = 100"

Or for a proprietary database, the equivalent command:

sql = "SELECT * FROM %s WHERE ROWNUM<=100"

Then run rake extract_fixtures

You’ve made your testbed so you can lie in it.

You now have and exact copy of your development database, and a collection of sample data in Yaml format, and are ready to begin writing some Unit Tests. Stay tuned for some examples. Rail on!

Posted in Create | Tags database, rails, rake, ruby, unit tests, yml | no comments

The Unselfish Act of Writing Tests

Posted by Mike Blake Wed, 14 Feb 2007 21:07:00 GMT

ORUG

At this months Orlando Ruby User’s Group meeting, I did my Testing on Rails presentation. In it I touched on just some of the benefits of having an automated suite of Unit, Functional, and Integration tests.

Later I thought of another major benefit. Tests help other people on the project, in addition to the author of the test.

Good Habits are Contagious

Recently I had the opportunity to work on a project with Harris Reynolds. Harris did something very important that sadly, you don’t see on every Rails Project. He wrote a unit test. Lot’s of us wrote tests , but this particular test stood out for two reasons. The first was when it was written.

Writing Tests First

Harris had found a bug in a model object that I had created. To notify me, he checked in an assertion that failed, then emailed me. This saved me time searching thought and remembering code I had written. I simply typed rake test:recent which runs all recently changed tests in a Rails application . The error took me right to the problem, and I immediately fixed the bug.

Testing a Deployment

The second reason I remember this test happened at least a month later. The application was being deployed to a new machine, and the test failed. The particular model object being tested pointed to a different database that the rest of the application, and it turned out that that database hadn’t been installed correctly on the new machine. Harris’s test told the problem straight away, and saved time once again.

Unit Testing: the gift that keeps on giving.

Thanks Harris!

Posted in Create | Tags ORUG, rails, ruby, unit tests | no comments

New Rails Site: FanNation

Posted by Mike Blake Thu, 21 Sep 2006 17:25:00 GMT

The folks at FanNation have done something that no one else in the sports world has done. They’ve created a comprehensive site for sports fans to gather and share information about their favorite teams and players (fantasy too) , and it’s all free.

I spent some time with the developers at FanNation working on the map on the home page. They are a sharp bunch, and I’m constantly amazed at the features they are adding each time I visit. Fannation is now one of the biggest websites around developed on Ruby on Rails. Tag clouds, in place edits, Dynamic news updates using AJAX calls, personalized blogging. This site is a tremendous example of practical usage of some of the latest technologies. And it’s loads of fun.

There’s tons of other functionality I haven’t explored yet, but definitely keep an eye on FanNation!

Posted in Create | Tags fannation, rails, ruby | 1 comment

Attend a Hackfest!

Posted by Mike Blake Tue, 12 Sep 2006 14:30:00 GMT

If you’re a programmer like me you’re a little intimidated by the Hackfest. That is , you’ve had several programming gigs over the years, attended a few more day long meetings than you’d have liked, and fear that you’ll be embarrassed by your perceived lack of skill compared to the young whiz kids with a burning passion for creating software.

We’ll let me assure you, the spirit of the hackfest is one of learning and cooperation and not at all that of oneupmanship or competition. At least not at the ORUG .

I had a blast this past weekend and learned a lot from my piers, and left with the feeling that I had helped out as well.

So my advice, fear not and attend a Hackfest!

Posted in Create | Tags hackfest, ORUG, rails, ruby | 1 comment

Ruby Namespace Conflicts

Posted by Mike Blake Sat, 15 Jul 2006 10:30:00 GMT

Declare new Classes Inside Modules to Avoid Conflicts

In the ruby language you cannot have a Module with the same name as a Class. The reason is that in any instance of the ruby interpreter, all root level accessible Objects are stored in a Hash of constants as either Modules or Classes. This can get cluttered pretty quickly in a large application. Try throwing the line 'p Module.constants' in the middle of a medium sized Rails application.

However, if a class is part of a Module, which acts as a namespace in ruby, it’s name never makes it to Module.constants. So it can have the same name as an existing Module.

To see a demonstration of this, I executed the following ruby code.

module One
end

class Two
  def self.to_s
    "2"
  end
end
p Two

class One::Two
  def self.to_s
    "1::2"
  end
end
p One::Two

class One::Three
  def self.to_s
    "1::3"
  end
end
p One::Three


p Module.constants

class One::One
  def self.to_s
    "1::1"
  end
end
p One::One

class One
  def self.to_s
    "1"
  end
end
p One

Here’s what happened. (output below). A Module named One was created and so was a class named Two. And the interpreter saw that it was good. Then, in the One module, classes One, Two, and Three were created. And the interpreter saw that it was good.

Then I took a peek at Module.constants. The One Module, and the Two Class were saved as constants. But the Three Class was not stored as a constant because it is not at the root level. Since Classes created within Modules are not stored as constants,I was allowed to create a One Class inside the One Module without a getting a TypeError.

But all is not well in paradise. When the program tried to create a class named One it got the error

-:35: One is not a class (TypeError)

That’s because it’s already stored in constants as a Module.

As Ruby grows in popularity, this could become a problem. Especially in the Rails framework where all Model objects are at the root level. Considering this, it’s a good habit to use modules as namespaces when creating new classes in things like plugins and gems to avoid a TypeError.

Output:

1::2

1::3

2

["TrueClass", "FloatDomainError", "Fixnum", "TOPLEVEL_BINDING", "SignalException", "String", "SystemCallError", "UnboundMethod", "Buffering", "Rational", "ThreadGroup", "CROSS_COMPILING", "ScriptError", "MatchData", "Thread", "IndexError", "STDOUT", "One", "SecurityError", "Integer", "SingleForwardable", "Config", "RELEASE_DATE", "Exception", "NoMethodError", "Proc", "GC", "TypeError", "Binding", "Signal", "FALSE", "RUBY_PLATFORM", "Forwardable", "Bignum", "SystemExit", "Date", "NotImplementedError", "EOFError", "FileTest", "TRUE", "Numeric", "Interrupt", "ARGF", "Array", "SyntaxError", "MatchingData", "RUBY_VERSION", "ParseDate", "Time", "RangeError", "ENV", "NIL", "Enumerable", "Module", "PLATFORM", "STDERR","Two", "NoMemoryError", "Float", "Regexp", "DateTime", "Data", "ZeroDivisionError", "ARGV", "Dir", "Process", "Range", "ThreadError", "ArgumentError", "Object", "IO", "Comparable", "LocalJumpError", "Math", "Marshal", "RuntimeError", "STDIN", "Method", "VERSION", "RegexpError", "Hash", "Precision", "Kernel", "Continuation", "File", "SystemStackError", "OpenSSL", "FalseClass", "Errno", "NilClass", "StandardError", "LoadError", "ObjectSpace", "RUBY_RELEASE_DATE", "Gem", "IOError", "Symbol", "Struct", "NameError", "Class"]