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.

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

: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.

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.

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

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.