Overriding a single Rails core file (batches.rb)

rubyonrails-talk
1

Hi everyone,

I'm trying to find a way to implement a diff I found into my application (Tickets - Ruby on Rails - rails 2137-allow-find_batches-to-use-order-limit-and-offset). It is imperative that I use find_in_batches as well as passing an :order option to the function. Certain rows need to be processed before others, and because of the size of the table I can't do them all at once.

Now, my question is, how could I do this with the least amount of fuss? I don't want to edit the batches.rb in my Rails installation, as I then would have to do the same on servers and other workstations. I also don't particularly want to freeze Rails. I've tried just slapping a new batches.rb into /vendor/rails/activerecord/lib/active_record/, hoping that that would override just that file, but it doesn't seem to work.

Any help would be appreciated!

Best regards, Sebastian

2

Sebastian,

Since it's an ActiveRecord module that gets included into AR::Base, you either need to:

1) (Sneaky) Load your own Batches module when AR wants to autoload it (active_record.rb:51) - override Module#autoload to 'listen' for the Batches module, and substitute your version (located in /lib or something) instead. You'll have to do this before Rails loads AR, though, so put it in /config/preinitializer.rb.

2) (More sane) Monkey-patch the changed methods into AR::B through a file you include in /lib, /config/initializers or through your own plugin. You would probably be overriding #find_in_batches, #sort_batch_rows! and #select_batch_ids.

3) Freeze rails, replace the file. This is the simplest, and least error-prone, though upgrading and patching Rails may be trickier.

Colin

3

Colin,

Thanks!

I will most likely go with option 2. Can I just copy-paste the modified methods as per the diff into any of those directories (obviously with "module ActiveRecord" and "module Batches" at the top)? Do I need to adhere to a specific naming scheme for the file?

Apologies for all the questions. I'm still (re-)learning Rails.

Best regards, Sebastian

4

Nevermind, figured it out.

Thanks again!

- Sebastian