Class: PageSweeper

Inherits:
ActionController::Caching::Sweeper
  • Object
show all
Defined in:
app/models/page_sweeper.rb

Overview

While sweepers are model observers, they only seem to be so within the scope of a given controller. If the ‘cache_sweeper’ line is not given in the controller, these observers don’t see it. In addition, saving or destroying a page outside of the scope of the controller (ie. from console) will also go unnoticed.

Interestingly, in unit/model testing, this fails as request is nil. This means that I don’t quite understand how this works. Perhaps because the cache is in memory and not a file, the server and console are completely separate. Destroying in the console doesn’t effect the server’s cache. That makes sense. So then. How to get the host_with_port without a request then?

Instance Method Summary collapse

Instance Method Details

#after_destroy(page) ⇒ Object

After destroying a page, expire any associated caches.



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# File 'app/models/page_sweeper.rb', line 28

def after_destroy(page)
	expire_cache(page)
end

#after_save(page) ⇒ Object

After saving (creating or updating) a page, expire any associated caches.



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# File 'app/models/page_sweeper.rb', line 22

def after_save(page)
	expire_cache(page)
end

#expire_cache(page) ⇒ Object

Always expire the menu cache. This may not be necessary as it only relies on the menu, path and position attributes which may have remained unchanged. Also expire the “show” action cache. As the pages are rarely accessed via /pages/:id, we need to expire the special routes used by the catch-all route. In the real world, this works just fine, but in testing the app tries to expire cache when in unit tests as well as functional tests. There is no “request” in a unit test causing failure and my usage of “.try”



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# File 'app/models/page_sweeper.rb', line 44

def expire_cache(page)
	#	Please note that the "views/" prefix is
	#	internal to rails.  Don't meddle with it.

	#	Expired fragment: views/page_menu (0.0ms)
	expire_fragment 'page_menu'

	#	We don't really access the pages via :id
	#		but they can be so we need to deal with the cache.
	#	Expired fragment: views/dev.sph.berkeley.edu:3000/pages/1 (0.0ms)
	#	Expired fragment: views/dev.sph.berkeley.edu:3000/pages/5 (0.0ms)
	expire_action

	#	Expired fragment: views/dev.sph.berkeley.edu:3000/alpha (0.0ms)
	#	Expired fragment: views/dev.sph.berkeley.edu:3000/ (0.0ms)
	#	This fails for the home page as "/" is 
	#		called "index" by the server
	#	NEEDS to change page.path to /index for home page
	#		be views/dev.sph.berkeley.edu:3000/index !
	page_path = ( page.path == "/" ) ? "/index" : page.path
#		expire_fragment "#{request.host_with_port}#{page_path}"
	expire_fragment "#{request.try(:host_with_port)}#{page_path}"

	#	In production, the page caches weren't expiring
	#	Adding the relative_url_root should fix it.
	page_path = ActionController::Base.relative_url_root.to_s + page_path
	expire_fragment "#{request.try(:host_with_port)}#{page_path}"

end