Calculating Time difference in Ruby

require 'date'
now = DateTime.new
date = Date.new
p now.strftime("%Y-%m-%d %I:%M:%S").to_s
p Time.now.strftime("%Y-%m-%d %I:%M:%S").to_s
dif = DateTime.parse(Time.now.strftime("%Y-%m-%d %I:%M:%S").to_s)-DateTime.parse("2007-9-12 14:07:00")
hours, mins, secs, ignore_fractions = Date::day_fraction_to_time(dif)
p hours * 60 * 60 + mins * 60 + secs

Pdf-writer -- Images in simple table

When using pdf-writer using ruby programming language, simple table always gives option of using text in the rows. I did not have an option to use images inside simple table as it uses data as

attr_accessor :data
# An array of Hash entries. Each row is a Hash where the keys are the
# names of the columns as specified in #column_order and the values are
# the values of the cell.

The following is the code change in simpletable.rb file is required to use images in respected cells.

line : 647
if(line.match("::Image"))
pic = line.gsub("::Image","")
line = pdf.add_image_from_file(pic,pos[name], pdf.y-5, @image_width)
line =""
else
line = pdf.add_text_wrap(pos[name], pdf.y,
max_width[name], line,
@font_size, just)
end


Note: Make sure that text should have "::Image" and remaing text is the path of the image .

like

data[i]["Q1Image"] ="::Image"+Dir.getwd+"/public/images/status_#{p.status_q1_image}.jpg"

For more information please post your comments.

Anand Agarawala: BumpTop desktop is a beautiful mess

Ruby and Related Links

http://www.oreillynet.com/ruby/blog/2006/05/post.html
(Zed on Ruby, Rails, Mongrel, and More)
Rails:
http://www-128.ibm.com/developerworks/java/library/j-cb08016/

Rails Deployment:
http://blog.duncandavidson.com/2005/12/deploying_rails.html
http://www.infoq.com/news/2006/12/deploy-rails-on-iis

Rails Migrations:
http://glu.ttono.us/articles/2005/10/27/the-joy-of-migrations
http://garrettsnider.backpackit.com/pub/367902

Scriptaculous Rails:
http://script.aculo.us/
http://www.juixe.com/techknow/index.php/2006/08/12/scriptaculous-rails/

Rest:
http://www.b-simple.de/documents

Second Life:
http://secondthoughts.typepad.com/second_thoughts/2006/06/getting_started.html
http://nwn.blogs.com/

Design Patterns:
http://www.dofactory.com/Patterns/Patterns.aspx

Agile SD:
http://www.adaptivesd.com/articles/cross_oct02.pdf

Arjun Singh and the Love Goddess!

So what does the Love Goddess have to do with Arjun Singh and with reservations? As the Indian government, at the behest of Arjun Singh, rolled out yet another short sighted policy to deal with the horrible caste system, we found out about some other activities of Arjun Singh.

ExampleDesignPatternsInRuby (Ruby)

Almost all of these examples are correct Ruby programs. If example output is shown, you should be able to copy code from the web page, run it in a Ruby interpreter and get the documented output.

Patterns

• AbstractFactoryPattern
• AbstractSessionPattern
• AdaptorPattern
• BouncerPattern
• ChainOfResponsibilityPattern
• CommandPattern
• CompositePattern
• DecoratorPattern
• DelegatorPattern
• FactoryMethodPattern
• FlyweightPattern
• IteratorPattern
• NullObjectPattern
• ObserverPattern
• ProductTraderPattern
• ProxyPattern
• RepositoryPattern
• SingletonPattern
• StatePattern
• StrategyPattern
• TemplateMethodPattern
• VisitorPattern

Source:http://wiki.rubygarden.org/Ruby/page/show/ExampleDesignPatternsInRuby

Design Patterns in Ruby : Observer

The key ideas around the Ruby implementation of the Observer pattern are:

1. Require the observer library
2. Mixin the Observable module to your class which can be observed
3. In the class that does the observing, implement the update method

That’s it.

Of course, an example would be nice. Here’s a small one.

require 'observer'  # Key step 1

class MyObservableClass
  include Observable  # Key step 2

  def blah
    changed  # note that our state has changed
    notify_observers( 5 )
  end
end

class MyObserverClass
  def update(new_data)  # Key step 3
    puts "The new data is #{new_data}"
  end
end

watcher = MyObservableClass.new
watcher.add_observer(MyObserverClass.new)

Now, any time that MyObservableClass#blah is called, the observing classes will get notified. In this example, we aren’t dynamically changing the data (in fact, it always stays constant), but I think you can see that if in fact the data DID change, the observers would all get notified of that change.