= cacheability

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[http://tomayko.com/src/rack-cache] documentation for more information.

Currently, cacheability comes with a rest-client[http://github.com/archiloque/rest-client] adapter, but the principle is easily applicable to other HTTP libraries.

= Installation

gem install cacheability

= Usage 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 - http://www.w3.org/Protocols/rfc2616/rfc2616-sec13.html
• Things Caches Do - http://tomayko.com/writings/things-caches-do

= Supported libraries

• rest-client > 0.9

= Dependencies

• rack-cache >= 0.5

= COPYRIGHT

Copyright (c) 2008 Cyril Rohr. See LICENSE for details.