Not sure were you got all of this code from… were you following an example somewhere?
This appears to be way overcomplicated for your use case. The definitive and nearly ubiqutious method for simple object caching (incidentally, the singular form is spelled "cache," as in a small hiding place. The word comes from the French, not to be confused with cachet, which also comes from French, and means "superior status" or "prestige") is from the DHH post from 2013… https://signalvnoise.com/posts/3113-how-key-based-cache-expiration-works Assuming your objects are ActiveResource objects, you automatically get cache_key defined for you. All you need to do is wrap the expensive (processing/time-intensive) code in the caching mechanism Rails.cache.fetch(@contact) // serialize or render the response data end … that's it. As explained in DHH's post from 2013, cache_key on @contact automatically includes the timestamp of when the record was last updated. When you make a change to any field the update_at timestamp changes, and so does the cache key, invalidating all caches associated with that cache key. All of the other code you have looks like you went down a caching rabbit hole that is unnecessary. (But learning the internals of the Rails caching mechanism is a good thing for your own edification!) -Jason > On Jun 18, 2017, at 2:51 AM, Arup Rakshit <[email protected]> wrote: > > I have the below code: > > class ContactsController < ApplicationController > > # .. > > def top_3 > cache_identifiers = { contact_1: 1, contact_2: 2, contact_3: 3 } > cache_keys = cache_identifiers.keys > cached_keys_with_values = Rails.cache.read_multi(*cache_keys) > uncached_keys = cache_keys.map { |key| key unless > cached_keys_with_values.has_key?(key) }.compact > uncached_ids = uncached_keys.map { |key| cache_identifiers[key] } > uncached_contacts = Contact.where(id: uncached_ids).to_a > > uncached_keys.zip(uncached_contacts).each do |key, value| > Rails.cache.write(key, value) > end > > @contacts = cache_keys.map do |key| > cached_keys_with_values[key] || uncached_contacts.shift > end > end > end > > I am using memcached as cache store. Now my question is how can I invalidate > the cache when say any of the attributes(name, email) of the contact record > changes. > > -- > You received this message because you are subscribed to the Google Groups > "Ruby on Rails: Talk" group. > To unsubscribe from this group and stop receiving emails from it, send an > email to [email protected] > <mailto:[email protected]>. > To post to this group, send email to [email protected] > <mailto:[email protected]>. > To view this discussion on the web visit > https://groups.google.com/d/msgid/rubyonrails-talk/13256849-6db8-47f9-97e8-c51688d54ba7%40googlegroups.com > > <https://groups.google.com/d/msgid/rubyonrails-talk/13256849-6db8-47f9-97e8-c51688d54ba7%40googlegroups.com?utm_medium=email&utm_source=footer>. > For more options, visit https://groups.google.com/d/optout > <https://groups.google.com/d/optout>. ---- Jason Fleetwood-Boldt [email protected] http://www.jasonfleetwoodboldt.com/writing If you'd like to reply by encrypted email you can find my public key on jasonfleetwoodboldt.com <http://jasonfleetwoodboldt.com/> (more about setting GPG: https://gpgtools.org) -- You received this message because you are subscribed to the Google Groups "Ruby on Rails: Talk" group. To unsubscribe from this group and stop receiving emails from it, send an email to [email protected]. To post to this group, send email to [email protected]. To view this discussion on the web visit https://groups.google.com/d/msgid/rubyonrails-talk/6BC11AD8-3FCA-418B-A0D5-9EBD3438CE5F%40datatravels.com. For more options, visit https://groups.google.com/d/optout.
