Dynamically generates sparkline graphs from a set of numbers. This is done primarily through Handlers and Cachers. Handlers know how to fetch the data, and Cachers know how to cache the generated PNG sparkline for future requests.

pub_dir   = File.expand_path(File.join(File.dirname(__FILE__), 'public'))
data_dir  = File.join(pub_dir, 'temps')
cache_dir = File.join(pub_dir, 'sparks')

use Sparkplug, :prefix => 'sparks',
  :handler =>,
  :cacher  =>
  • An incoming request hits your Rack application at “/sparks/foo/stats.csv”.

  • The CSV Handler gets 'foo/stats.csv', and checks for this file in its data directory. It parses the first row of numbers as the set of points to plot.

  • The Filesystem Cacher checks for a more recent cache. Failing that, it generates the PNG graph and writes it to the cache directory.

Mix and match your own handlers and cachers with your friends!


See demo/sparkplug_demo.rb or


gem install sparkplug

Copyright © 2009 rick. See LICENSE for details.