basic hit counter in redis

gistfile1.rb

#!/usr/bin/ruby
# Copyright (c) 2010,2011 Jonathan Stott
#
# Permission  is  hereby granted, free of charge, to any person ob-
# taining a copy of  this  software  and  associated  documentation
# files  (the "Software"), to deal in the Software without restric-
# tion, including without limitation the rights to use, copy, modi-
# fy, merge, publish, distribute, sublicense, and/or sell copies of
# the Software, and to permit persons to whom the Software is  fur-
# nished to do so, subject to the following conditions:
#
# The  above  copyright  notice and this permission notice shall be
# included in all copies or substantial portions of the Software.
#
# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF  ANY  KIND,
# EXPRESS  OR  IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES
# OF MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE  AND  NONIN-
# FRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
# LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER  IN  AN
# ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
# CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN  THE
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require 'redis'
require 'sinatra'
require 'yajl'
require 'digest/sha1'

set :url_set,    'urls'
set :all_hits, 'all_hits'

configure do
  REDIS = Redis.new
end


get '/' do
  etag(Digest::SHA1.hexdigest(REDIS.get("#{settings.url_set}:#{settings.all_hits}").to_s))
  result  = REDIS.sort(settings.url_set, :by => 'nosort', :get => ['#', "#{settings.url_set}:*"])
  hash = Hash[result]
  Yajl::Encoder.encode(hash) + "\n"
end

post '/' do
  url = params['url']
  REDIS.incr("#{settings.url_set}:#{url}")
  REDIS.sadd(settings.url_set, url)
  REDIS.incr("#{settings.url_set}:#{settings.all_hits}")
  ""
end