A gem that makes client-side caching of HTTP requests a no-brainer. It is built upon the Rack:Cache gem from Ryan Tomayko.
Cached data can be stored in heap, file or memcached. See the rack-cache documentation for more information.
Currently, cacheability comes with a rest-client adapter, but the principle is easily applicable to other HTTP libraries.
gem install cacheability
Using the rest-client HTTP library, you just need to require the restclient adapter and enable the caching component:
require 'cacheability/restclient'
# Enable the caching component, and store both meta and entity data in files:
# See http://tomayko.com/src/rack-cache/configuration for the list of available options
RestClient.enable :caching,
:metastore => 'file:/tmp/cache/meta',
:entitystore => 'file:/tmp/cache/body'
# ... done !
# Then you can make your requests as usual, and the resources will be automatically and transparently cached for you according to their HTTP headers.
# Cache invalidation on requests other than GET is also transparently supported, thanks to Rack::Cache. Enjoy !
RestClient.get 'http://some/cacheable/resource'
# or
resource = RestClient::Resource.new('http://some/cacheable/resource')
# obviously, caching is only interesting if you request the same resource multiple times, e.g. :
resource.get # get from origin server, and cache if possible
resource.get # get from cache, if still fresh.
resource.put(...) # will automatically invalidate the cache, so that a subsequent GET request on the same resource does not return the cached resource
resource.get # get from origin server, and cache if possible
# ...
resource.get(:cache_control => 'no-cache') # explicitly tells to bypass the cache, requires rack-cache >= 0.5 and :allow_reload => true option
# ...
resource.delete(...) # will invalidate the cache
resource.get # should raise a RestClient::ResourceNotFound exception
Now, you just need to make your resources cacheable, so unless you’ve already taken care of that, do yourself a favor and read:
-
the HTTP specification related to HTTP caching - www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
-
Things Caches Do - tomayko.com/writings/things-caches-do
-
rest-client > 0.9
-
rack-cache >= 0.5
Copyright © 2008 Cyril Rohr. See LICENSE for details.