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unique calculation using redis
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require 'sinatra' | |
require 'redis' | |
require 'json' | |
require 'date' | |
class String | |
def &(str) | |
result = '' | |
result.force_encoding("BINARY") | |
min = [self.length, str.length].min | |
(0...min).each do |i| | |
result << (self[i].ord & str[i].ord) | |
end | |
result | |
end | |
def |(str) | |
result = '' | |
result.force_encoding("BINARY") | |
min = [self.length, str.length].min | |
(0...min).each do |i| | |
result << (self[i].ord | str[i].ord) | |
end | |
if self.length > str.length | |
result << self[min ... self.length] | |
elsif self.length < str.length | |
result << str[min ... str.length] | |
end | |
result | |
end | |
def population_count | |
count = 0 | |
(0 ... self.length).each do |i| | |
count += _population_count_byte(self[i].ord) | |
end | |
count | |
end | |
private | |
ONE_BITS = [0,1,1,2,1,2,2,3,1,2,2,3,2,3,3,4] | |
#It works with 8 bits | |
def _population_count_byte(x) | |
count = 0 | |
count = ONE_BITS[x&0x0f] | |
count += ONE_BITS[x>>4] | |
count | |
end | |
end | |
helpers do | |
def redis | |
$redis ||= Redis.new | |
end | |
def unique_count(event, from, to) | |
uniques = '' | |
(from..to).each do |date| | |
key = "#{event}.#{date.strftime('%y%m%d')}" | |
bitmap = redis.get(key) | |
if bitmap | |
bitmap.force_encoding("BINARY") | |
uniques |= bitmap | |
end | |
end | |
uniques.population_count | |
end | |
end | |
get '/collect/:event/for/:user_id/on/:date' do |event,user_id,date| | |
time = Date.parse(date) | |
key = "#{event}.#{time.strftime('%y%m%d')}" | |
if redis.setbit(key, user_id, 1) | |
204 | |
else | |
500 | |
end | |
end | |
get '/unique/:event/in/last/:n/days?' do |event,n| | |
content_type :json | |
to = Date.today | |
from = to - n.to_i | |
{:from => from, :to => to, :unique_count => unique_count(event,from,to)}.to_json | |
end |
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