Manually Clear Fragment Cache in Rails

Question

I\'m using Memcached with Heroku for a Rails 3.1 app. I had a bug and the wrong things are showing - the parameters were incorrect for the cache.

I had this:

Answer 1

From the rails console:

Rails.cache.delete 'FRAGMENT-NAME'

Answer 2

Here you are:

<% ActionController::Base.new.expire_fragment("foo_header_cache_#{@user.id}") %>

Reference:
- How to call expire_fragment from Rails Observer/Model?

Answer 3

I ended up manually clearing the entire cache by going into the rails console and using the command:

Rails.cache.clear

Answer 4

From the console:

You can run this (ie. if you know the id is '1')

ActionController::Base.new.expire_fragment("foo_header_cache_1")

To use Rails.cache.delete you need to know the fragment name. In your case, it would be

Rails.cache.delete("views/foo_header_cache_1") # Just add 'views/' to the front of the string

If you have an array-based cache key using objects, such as:

cache([:foo_header_cache, @user])

Then you can get the fragment name like so

ActionController::Base.new.fragment_cache_key([:foo_header_cache, @user])

The name includes the id and updated_at time from any objects (to the yyyymmddhhmmss). It would be something like "views/foo_header_cache/users/1-20160901021000"

Or simply clear it using the array.

ActionController::Base.new.expire_fragment([:foo_header_cache, @user])