Using memcache-client 1.6.x in Rails < 2.3

Jemery Kemper recently upgraded Rails 2.3′s vendored copy of memcache-client to the 1.6.4 release. But what do you do if you are running Rails 2.1/2.2 and want to take advantage of the massive speedup in 1.6.x? You write some really ugly code that performs brain surgery on the Ruby environment to override ActiveSupport. Create config/initializers/memcache-client-upgrade.rb with this code:

require 'rubygems'
 
# Brain surgery to use our own version of memcache-client without
# having to modify activesupport directly.
# Unload any previous instance of the class
if Object.const_defined? :MemCache
  Object.instance_eval { remove_const :MemCache }
end
# Pull in the exact version we want
gem 'memcache-client', '1.6.5'
# Ensure that the memcache-client path is at the front of the loadpath
$LOAD_PATH.each do |path|
  if path =~ /memcache-client/
    $LOAD_PATH.delete(path)
    $LOAD_PATH.unshift(path)
  end
end
# If Ruby thinks it's already loaded memcache.rb, force
# a reload otherwise just require.
if $".find { |file| file =~ /\Amemcache.rb\Z/ }
  load 'memcache.rb'
else
  require 'memcache'
end

If someone knows of a cleaner way to do this, please let me know.

13 thoughts on “Using memcache-client 1.6.x in Rails < 2.3”

JGeiger 2009/03/03 at 10:03 am

Thanks.

fazibear 2009/03/13 at 6:09 am

It’s cleaner if you move it to config/initializers/memcache_fix.rb

mperham Post author2009/03/13 at 6:26 am

Thanks, good idea. I forgot that load order doesn’t matter since we’re unloading everything. I’ve updated the post.

fazibear 2009/03/13 at 6:44 am

Wait! I think it does matter. It won’t work from initializers scripts! But why ?

Jerrett 2009/05/13 at 7:32 pm

Yikes, that sucks. Hopefully they will add the 1.7.x to rails so we don’t have to do this

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Colin Surprenant 2009/06/10 at 11:23 pm

Thanks, that worked for me with memcache-client 1.7.4 and Rails 2.2.2.

I have also written a quick tutorial on how to do this and also control the MemCacheStore options using a memcached.yml config file (from cache_fu/acts_as_cached) on http://eventuallyconsistent.com/blog/2009/06/rails-memcachestore-fu/

Colin.