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.

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.

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

multitrack mandolins, nylon guitars,  and percusion.

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

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

• 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.

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.