This document discusses caching techniques in Rails, including: 1. Using cache digests to avoid worrying about cache dependencies and versioning. 2. Caching fragments and associations to improve performance when data changes. 3. Leveraging browser, CDN, and other edge caching to further improve page load speeds.

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% cache @user do %
%= render partial: 'user' %
% end %
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11. %P?EKCLR?AFGLE
cache small pieces of information instead of full pages
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= User id: 1, updated_at: 2014-10-02 18:12:57
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= users/1-20141002181257446781000
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= User id: 1 , updated_at: 2014-10-02 18:12:57
SQCPA?AFC=ICW
= users/1-20141002181257446781000
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16. % cache @user do %
%= render partial: 'user' %
% end %
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17. % cache @user do %
%= render partial: 'user' %
% end %
%GPQRRGKCUCJM?BRFCN?EC
Read fragment views/users/1-20141002181257446781000/
95a652b13f0fc5b7bc8785ac31b6b8b9 (1.2ms)
Write fragment views/users/1-20141002181257446781000/
95a652b13f0fc5b7bc8785ac31b6b8b9 (1.2ms)
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Read fragment views/users/1-20141002181257446781000/
95a652b13f0fc5b7bc8785ac31b6b8b9 (1.2ms)
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19. class Project
has_many :todo_lists
class TodoList
belongs_to :project, touch: true
has_many :todos
class Todo
belongs_to :todo_list, touch: true
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21. - @projects.each do |project|
- cache ['project', project] do
...project
- project.todo_lists.each do |todo_list|
- cache ['todo_list', todo_list] do
...todo list
- todo_list.todos.each do |todo_list|
- cache ['todo', todo] do
...todo
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- @projects.each do |project|
- cache ['v1', 'project', project] do
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23. 1?GJQQMJTCQRFGQNPM@JCKUGRFA?AFCBGECQRQ
A call to #cache in your views will now suffix a digest of the template and its
dependencies. No longer will you need to worry about fragment cache
dependencies and versioning!
user.cache_key
= users/1-20141002181257446781000
Read fragment views/users/1-20141002181257446781000/
95a652b13f0fc5b7bc8785ac31b6b8b9 (1.2ms)
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24. 1?GJQQMJTCQRFGQNPM@JCKUGRFA?AFCBGECQRQ
A call to #cache in your views will now suffix a digest of the template and its
dependencies. No longer will you need to worry about fragment cache
dependencies and versioning!
user.cache_key
= users/1-20141002181257446781000
Read fragment views/users/1-20141002181257446781000/
95a652b13f0fc5b7bc8785ac31b6b8b9 (1.2ms)
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25. 1?GJQQMJTCQRFGQNPM@JCKUGRFA?AFCBGECQRQ
A call to #cache in your views will now suffix a digest of the template and its
dependencies. No longer will you need to worry about fragment cache
dependencies and versioning!
user.cache_key
= users/1-20141002181257446781000
Read fragment views/users/1-20141002181257446781000/
95a652b13f0fc5b7bc8785ac31b6b8b9 (1.2ms)
There's a gem for that
rails/cache_digests
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26. $VCPAGQC
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29. /CPQNCARGTCB?R?
Or how to make your cache useless
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31. .col-sm-12.no-lr-padding.ticket-info
.col-price-block
%span.top-line
From
%span.ticket-price.bottom-line
= formated_cheapest_ticket_price(activity)
.col-tickets-left-block
- unless activity.hide_remaining_tickets?
%span.color-default.top-line
Tickets left:
%span.bottom-line
= activity_tickets_left(activity)
.col-attendees-block
%span.top-line
Attendees:
%span.bottom-line
= activity_attendees_count(activity)
.user-buttons-block
%a.btn.btn-wishlist.btn-85
%span.event_wishlist_span
= wishlisted_label(activity, current_user)
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32. hit rate?
cache ['event', event] do
turns into:
cache ['event', event, current_user] do
Hit rate: 1 / Event.count * User.count
*probably should avoid
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.event-pod{data-wishlisted=#{
wishlisted_label(activity, current_user)}}
$('.event-pod').each(function(){
$(this).find('.wishlisted_button').html(
$(this.data('wishlisted'))
);
})
???
This is good if you want to decouple the usere data or generate it in
Also good for edge caching.
*extra complexity
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36. neighborland/cache_rocket
= render_cached 'outer', replace: 'inner'
outer.html.haml
- cache 'outer' do
.lots
.of
.htmls
= cache_replace_key 'inner'
inner.html.haml
= uncacheable_content
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38. @CLCDGRQ
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more hits
faster pages
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more hits
less RAM used
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41. def show
@article = Article.find(params[:id])
if stale?(:etag = @article, :last_modified
= @article.created_at.utc)
@statistics = @article.really_expensive_call
respond_to do |format|
# all the supported formats
end
end
end
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42. def show
@article = Article.find(params[:id])
if stale?(:etag = @article, :last_modified
= @article.created_at.utc)
@statistics = @article.really_expensive_call
respond_to do |format|
# all the supported formats
end
end
end
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43. def show
@article = Article.find(params[:id])
if stale?(:etag = @article, :last_modified
= @article.created_at.utc)
@statistics = @article.really_expensive_call
respond_to do |format|
# all the supported formats
end
end
end
= 304 Not Modified
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44. $BECA?AFGLE
Cloudfront
Akamai
fastly
Varnish...
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46. Cache-Control: public - Any cache can store a copy of the content.
Cache-Control: private - Don't store, this is for a single user.
Cache-Control: no-cache - Re-validate before serving this content.
Cache-Control: no-store - Don't store this content. Ever. At all. Please.
Cache-Control: public, max-age=[seconds] - Caches can store this content for n
seconds.
Cache-Control: s-maxage=[seconds] - Same as max-age but applies specifically
to proxy
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48. class SuggestionsController
def show
@users = Rails.cache.fetch(['users', params['page']]) do
# we need to call .all to hit the database otherwise
# we cache only the ruby query object
User.suggestions.page(params['page']).all
end
end
end
*all is for rails3
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ahawkins/cashier
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Instead of using updated_at to cause a cache miss, record where your objects
are cached
cache @something, tag: ['dashboard', 'settings']
@users = Rails.cache.fetch(['users', params['page']],
tag: 'users') do
# we need to call .all to hit the database otherwise
# we cache only the ruby query object
User.suggestions.page(params['page']).all
end
...
User#after_commit
...
Cashier.expire users
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cache 'homepage', expires_in: 1.hour do
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class NukesController
def create
expire_fragment('homepage');
end
end
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