From: Hemant Kumar <gethemant@...>
Date: 2007-01-24T05:12:52+09:00
Subject: Re: wrapping class method

On Wed, 2007-01-24 at 04:14 +0900, Ball, Donald A Jr (Library) wrote:
> Hey guys, I'm having trouble figuring out how to wrap a class method. I
> want to add a logger.debug to ActiveRecord::Base.establish_connection,
> just trying to figure out how the rails database connection lifecycle is
> supposed to work. I tried this naive approach:
> 
> module ActiveRecord
> 
>   class Base
> 
>     alias self.old_establish_connection self.establish_connection
> 
>     def self.establish_connection(arg)
>       logger.debug("Establishing connection")
>       self.old_establish_connection(arg)
>     end
> 
>   end
> 
> end
> 
> of course, ruby doesn't like this, the self.old_establish_connection bit
> throws a SyntaxError. How ought I go about doing this?
> 
> - donald
> 

Try this:

module ActiveRecord

  class Base

    class << self
      alias old_establish_connection establish_connection
    end

    def self.establish_connection(arg)
      logger.debug("Establishing connection")
      self.old_establish_connection(arg)
    end
  end
end

Another approach might be to use super like this:

module ActiveRecord
  class Base
    def self.establish_connection(arg)
      logger.debug("Establishing connection")
      super arg
    end
  end
end