Awesome
Rack::Cache
Rack::Cache is suitable as a quick drop-in component to enable HTTP caching for
Rack-based applications that produce freshness (expires
, cache-control
)
and/or validation (last-modified
, etag
) information:
- Standards-based (RFC 2616)
- Freshness/expiration based caching
- Validation (
if-modified-since
/if-none-match
) vary
supportcache-control
public
,private
,max-age
,s-maxage
,must-revalidate
, andproxy-revalidate
.- Portable: 100% Ruby / works with any Rack-enabled framework
- Disk, memcached, and heap memory storage backends
For more information about Rack::Cache features and usage, see:
https://rack.github.io/rack-cache/
Rack::Cache is not overly optimized for performance. The main goal of the project is to provide a portable, easy-to-configure, and standards-based caching solution for small to medium sized deployments. More sophisticated / high-performance caching systems (e.g., Varnish, Squid, httpd/mod-cache) may be more appropriate for large deployments with significant throughput requirements.
Installation
gem install rack-cache
Basic Usage
Rack::Cache
is implemented as a piece of Rack middleware and can be used with
any Rack-based application. If your application includes a rackup (.ru
) file
or uses Rack::Builder to construct the application pipeline, simply require
and use as follows:
require 'rack/cache'
use Rack::Cache,
metastore: 'file:/var/cache/rack/meta',
entitystore: 'file:/var/cache/rack/body',
verbose: true
run app
Assuming you've designed your backend application to take advantage of HTTP's caching features, no further code or configuration is required for basic caching.
Using with Rails
# config/application.rb
config.action_dispatch.rack_cache = true
# or
config.action_dispatch.rack_cache = {
verbose: true,
metastore: 'file:/var/cache/rack/meta',
entitystore: 'file:/var/cache/rack/body'
}
You should now see Rack::Cache
listed in the middleware pipeline:
rake middleware
Using with Dalli
Dalli is a high performance memcached client for Ruby. More information at: https://github.com/mperham/dalli
require 'dalli'
require 'rack/cache'
use Rack::Cache,
verbose: true,
metastore: "memcached://localhost:11211/meta",
entitystore: "memcached://localhost:11211/body"
run app
Noop entity store
Does not persist response bodies (no disk/memory used).<br/>
Responses from the cache will have an empty body.<br/>
Clients must ignore these empty cached response (check for x-rack-cache
response header).<br/>
Atm cannot handle streamed responses, patch needed.
require 'rack/cache'
use Rack::Cache,
verbose: true,
metastore: <any backend>
entitystore: "noop:/"
run app
Ignoring tracking parameters in cache keys
It's fairly common to include tracking parameters which don't affect the content
of the page. Since Rack::Cache uses the full URL as part of the cache key, this
can cause unneeded churn in your cache. If you're using the default key class
Rack::Cache::Key
, you can configure a proc to ignore certain keys/values like
so:
Rack::Cache::Key.query_string_ignore = proc { |k, v| k =~ /^(trk|utm)_/ }