Missing template error on when background processing - ruby-on-rails

Question

I am using background processing with the resque gem and bioruby, and the processing is correctly functioning. I am however getting a "missing template" error. It seems the action is trying to load a template.
Missing template cosmics/start_batch, application/start_batch with {:locale=>[:en],
:formats=>[:html], :handlers=>[:erb, :builder, :coffee]}.
I do not want a template loaded: the background process retrieves data from an external source and then updates a database table (this is all working).
The code is triggered by a button:
<%= link_to 'Process', start_batch_path, :class =>"btn btn-primary" %>
config/routes.rb
match '/cosmics/start_batch', :to => 'cosmics#start_batch', :as => 'start_batch'
resources :batches do
resources :batch_details
end
cosmics_controller.rb
def start_batch
#batch = Batch.create!(:status => 'created',:status_timestamp => Time.now)
#cosmics = Cosmic.find(:all, :conditions => {:selected => true}).each do |cosmic|
#batch_detail = BatchDetail.create!(:batch_id => #batch.id, :cosmic_mut_id => cosmic.cosmic_mut_id)
#batch_detail.save
cosmic.selected = false
cosmic.save
end
Resque.enqueue(UcscQuery,#batch.id)
end
workers/ucsc_query.rb (Reqsue worker class)
class UcscQuery
require 'bio-ucsc'
include Bio
#queue = :ucsc_queue
def self.perform(batch_id)
Ucsc::Hg19.connect
#batch_detail = BatchDetail.find(:all, :conditions => {:batch_id => batch_id}).each do |batch_detail|
ucsc_cosmic = Ucsc::Hg19::Cosmic.find_by_name(batch_detail.cosmic_mut_id)
if ucsc_cosmic
batch_detail.bin = ucsc_cosmic.bin
batch_detail.chrom = ucsc_cosmic.chrom
batch_detail.chrom_start = ucsc_cosmic.chromStart
batch_detail.chrom_end = ucsc_cosmic.chromEnd
batch_detail.status = 'processed'
batch_detail.save
end
end
Batch.update(batch_id, :status => 'located')
end
end
How can I prevent Rails from trying to load a cosmics/start_batch template? Any refactoring tips would also be appreciated.

Answer 1

If there is no render nor redirect instruction in a controller method, Rails looks for a view with the same name of the method. To change this behavior, add render :nothing => true at the end of the start_batch method.
With this, when the user will click on the Process link, it will render a blank page. That's certainly not what you want. You can use :remote => true option in the link_to so the user will stay on the current page:
<%= link_to 'Process', start_batch_path, {:remote => true}, {id: 'process_btn', :class => "btn btn-primary"} %>
Finally, use javascript to show the user that "something" happened when he clicked on the button. Example:
$('#process_btn').on('click', function() { alert('Batch process started'); };

Answer 2

You can simply type:
render :nothing => true
in your action. I would also advice changing your link to remote
<%= link_to 'Process', start_batch_path, :class =>"btn btn-primary", :remote => true %>
Otherwise you'll see blank page after clicking on it.