rails template

March 25, 2009

Usage $ rails app_name -m ./ahabman_template.rb


run "rm README"
run "rm public/index.html"
run "rm public/favicon.ico"
run "rm public/robots.txt"
run "rm -f public/javascripts/*"

gem 'ruby-openid', :lib => 'openid'
rake("gems:install", :sudo => true)

plugin "kamui_restful_authentication", :git => 'git://github.com/kamui/restful-authentication.git'
plugin 'exception_notifier', :git => 'git://github.com/rails/exception_notification.git'
plugin 'open_id_authentication', :git => 'git://github.com/rails/open_id_authentication.git'
#plugin 'asset_packager', :git => 'http://synthesis.sbecker.net/pages/asset_packager'
plugin 'role_requirement', :git => 'git://github.com/timcharper/role_requirement.git'
#plugin 'acts_as_taggable_redux', :git => 'http://github.com/geemus/acts_as_taggable_redux/tree/master'
#plugin 'restful-authentication', :git => 'git://github.com/technoweenie/restful-authentication.git'

generate("authenticated user sessions --include-activation --include-forgot-password --email-as-login")
generate("roles", "Role User")

#rake('acts_as_taggable:db:create')
rake("open_id_authentication:db:create")
rake('db:migrate')

route "map.root :controller => 'sessions', :action => 'signup' "

run "echo generated from ahabman_template > README"
run "cp config/database.yml config/example_database.yml"

#if yes?("Do you want this thing?")
# ...
#end

#my_var = ask("was up")
#generate :something, my_var

puts "SUCCESS!"
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ruby on rails – has and belongs to many view plugin

October 16, 2008

So I’ll never have to write another has_and_belongs_to_many view again, here’s a plugin that dynamically makes 2 <ul> lists which you drag and drop both ways to manage the association.

http://svn.ahabman.com/public/many_to_many_view/

From the readme:

Assumming you have an @project var and you want to associate people with it.

<div id="m2m_container">
<%= render :partial => "shared/m2m", :locals => {
:thing => @project,
:association => 'people',
:association_attr => 'first_name' }   %>
</div>

:thing take the current object
:association takes the pluralized association, a string.
:association_attr takes the attribute of the associated object that will be displayed.

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You can’t use class variables in rails.

October 15, 2008

You can’t use class variables in rails.  Unless you’d like to develop in production mode (specifically with config.cache_classes = true).  In development mode all classes are reloaded on each request, which clears all class variables.

I had the perfect place to use them – while running a mass synchronization, and needing to store the timestamp (I couldn’t use the latest last_updated from each record).  It worked perfect in ./script/console but failed entirely through the browser.

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ruby csv to structured hash

September 18, 2008

I had a csv like this:

object color flavor shape
apple red sweet round
banana yellow sweet long
lemon yellow sour round

and I wanted a ruby hash structured like this:

{
'apple'=> { 'color'=>'red',  'flavor'=>'sweet', 'shape'=>'round'},
'banana'=> {  'color'=>'yellow',  'flavor'=>'sweet', 'shape'=>'long'},
'lemon'=> {   'color'=>'yellow',  'flavor'=>'sour', 'shape'=>'round'}
}

So I wrote this, which does the job:

require "faster_csv"

def csv_to_structured_hash
	arr_of_arrs = FasterCSV.read( 'your.csv' )
	stuff = {}
	header = arr_of_arrs.shift
		arr_of_arrs.each_with_index do |row, i|
		thing = { row[0] => {} }
			header.each_with_index do |col, header_index|
			thing[ row[0] ][ header[header_index] ] = row[ header_index]
			end
		stuff.update( thing )
		end
	return stuff
end
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Ruby conversion module

July 2, 2008

This is a ruby module useful for conversions dealing with length, weight, torque.

 module Convert 

   def Convert.number_with_precision(number, precision=2)
     "%01.#{precision}f" % number
   rescue
     number
   end 

   def Convert.mm_to_in(mm, precision=2)
     number_with_precision(mm * 0.03937, precision)
   end 

   def Convert.in_to_mm(inches, precision=2)
     number_with_precision(inches / 0.03937 , precision)
   end 

   def Convert.feet_to_meters(f, precision=2)
     number_with_precision( f * 0.3048, precision)
   end 

   def Convert.meters_to_inches(m, precision=2)
     number_with_precision( m * 39.37, precision)
   end 

   def Convert.meters_to_feet(m, precision=2)
     number_with_precision( m * 3.281, precision)
   end 

   def Convert.kg_to_lbs(kg, precision=2)
     number_with_precision( kg * 2.2   , precision)
   end 

   def Convert.lbs_to_kg(lbs, precision=2)
     number_with_precision( lbs / 2.2   , precision)
   end 

   def Convert.nm_to_inch_pounds(nm, precision=1)
     number_with_precision( nm * 8.850   , precision)
   end 

   def Convert.inch_pounds_to_nm(inlb, precision=1)
     number_with_precision( inlb / 8.850   , precision)
   end 

 end
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Rails redirect_to :back in Internet Explorer

June 6, 2008

Today I realized that the rails command   redirect_to :back  does not work in Internet Explorer because  redirect_to :back  depends on the HTTP_REFERER http header, which IE does not send.  I was capturing an onclick event with jQuery and was able to sending along the  current URL as a query string, which provided an easy way around this limitation.

In the view:

<script>
    $jQuery('#myLink').click(function(){
        window.location.href = 'theDestinationPage/?current_url=' + document.location ;
    })
</script>

In the controller:

def myAction
    .....
    redirect_to params[:current_url]
end
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Rails background process – simple, fast, easy.

May 31, 2008

My situation was this -

  • Rails 2.0 app running on slicehost (ubuntu 8.04) in passenger mod_rails
  • The goal was Dynamic PDF generation for a product catalog ( > 100 pages)
  • This event had to be triggered from within the rails request / response cycle, but run outside of it
  • I needed the simplest, fastest, more reliable way for this to happen

I looked at BackgroundRB, it is the most robust, well documented solution available.  But it was overkill since I didn’t need status feedback and my time was very limited (backgroundRB setup seems somewhat involved).  And, I wasn’t sure how it would interact with Passenger mod_rails – although FooBarWidget mentioned on IRC that it should work as expected.

I looked at Spawn plugin which supports threading and forking ruby processes.   No luck – setting it one way never ran inside mod_rails and setting it the other way tied up the request response cycle.

All the ruby code was in place, except for how to detach this process from the request/response cycle, when severnspoon provided this
Simple, Easy, One-Line Solution:

My_Controller
  def generate_pdf_in_background

    system " RAILS_ENV=#{RAILS_ENV}   ruby  #{RAILS_ROOT}/script/runner   'MyModel.create_pdf_in_background'  & "

  end
end

That ampersand was all I needed.  It runs the command as a background process.  A new ruby process is kicked off, and the 10 minute task runs perfectly.  Something makes the browser hang and wait for a response, but we confirmed that other requests can happen along side this.

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mod_rails set RAILS_ENV variable to QA, Staging, or Production

May 23, 2008

I’m using mod_rails with capistrano and multi-stage (qa, staging, production), and wrote this workaround so that the RAILS_ENV could be set correctly in each stage.  Mod_rails sets RAILS_ENV once in the global server conf file, but I needed it set once for each environment: qa, staging, and production.  I tried setting ENV['RAILS_ENV] in each file under config/deploy/ but the setting was not picked up.

Solution – write the correct value into config/environment.rb’s  ENV[''RAILS_ENV] while deploying.

So here is my 3 step fix -

Step 1.

I created a new file

lib/set_mod_rails_env.rb

# sets ENV['rails_env'] for mod_rails
# http://www.megasolutions.net/ruby/search-a-file-and-replace-text-50116.aspx
# Robert Evans'
def ChangeOnFile(file, regex_to_find, text_to_put_in_place)
  text = File.read file
  File.open(file, 'w+'){|f| f << text.gsub(regex_to_find,
      text_to_put_in_place)}
end
ChangeOnFile("#{ARGV[0]}/config/environment.rb", /#mod_rails_env_here/, "ENV['RAILS_ENV']='#{ARGV[1]}'")

Step 2.

Add the following code to config/deploy.rb

namespace :deploy do
desc "set ENV['RAILS_ENV'] for mod_rails"
task :before_restart do
run "ruby #{current_release}/lib/set_mod_rails_env.rb  #{current_release}  #{stage}"
end
end

Step 3.

Add the following code to config/environment.rb

# deploy.rb will swap this out for the appropriate rails_env.
# mod_rails apparently need this var in this file (not ./environments/qa.rb)
# do not change the following line. Ruby regexp looks for it.
#mod_rails_env_here

That’s it.  Let me know if you know of an easier way.

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