Lightly - Ruby File Cache
Lightly is a file cache for performing heavy tasks, lightly.
$ gem install lightly
Or with bundler:
Lightly can be used both as an instance, and as a static class.
require 'lightly' # Instance lightly = . life: '3h' response = lightly.get 'key' do # Heavy operation here end # Static . = '3h' response = . 'key' do # Heavy operation here end
The design intention is to provide both a globally available singleton
Lightly object, as well as multiple caching instances, with different
settings - depending on the use case.
Note that the examples in this document are all using the instance syntax, but all methods are also available statically.
This is the basic usage pattern:
require 'lightly' lightly = . content = lightly.get 'key' do # Heavy operation here entire_internet.download end
This will look for a cached object with the given key and return it if it exists and not older than 1 hour. Otherwise, it will perform the operation inside the block, and save it to the cache object.
By default, the cached objects are stored in the
./cache directory, and
expire after 60 minutes. The cache directory will be created as needed.
In addition, the provided key is hashed to its MD5 representation.
You can change these settings on initialization:
lightly = . dir: 'tmp/my_cache', life: 7200, hash: false
lightly = . lightly.dir = 'tmp/my_cache' lightly.life = '1d' lightly.hash = false
life property accepts any of these formats:
lightly.life = 10 # 10 seconds lightly.life = '20s' # 20 seconds lightly.life = '10m' # 10 minutes lightly.life = '10h' # 10 hours lightly.life = '10d' # 10 days
To check if a key is cached, use the
lightly = . lightly.cached? 'example' # => false content = lightly.get 'example' do open('http://example.com').read end lightly.cached? 'example' # => true
You can enable/disable the cache at any time:
lightly = . lightly.disable lightly.enabled? # => false content = lightly.get 'example' do open('http://example.com').read end lightly.cached? 'example' # => false lightly.enable content = lightly.get 'example' do open('http://example.com').read end lightly.cached? 'example' # => true
To flush the cache, call:
lightly = . lightly.flush
To clear the cache for a given key, call:
lightly = . lightly.clear 'example'
To clear all expired keys, call:
lightly = . lightly.prune
If your block returns
nil, the data will not be cached:
result = lightly.get 'test' do false end puts lightly.cached? 'test' # => false
For a similar gem that provides caching specifically for HTTP downloads, see the WebCache gem.
Contributing / Support
If you experience any issue, have a question or a suggestion, or if you wish to contribute, feel free to open an issue.