Redis auto-completion

compl1.rb

# compl1.rb - Redis autocomplete example
# download female-names.txt from http://antirez.com/misc/female-names.txt

require 'rubygems'
require 'redis'

r = Redis.new

# Create the completion sorted set
if !r.exists(:compl)
  puts "Loading entries in the Redis DB\n"
  File.new('female-names.txt').each_line do |n|
    n.strip!
    1.upto(n.length).each do |l|
      prefix = n[0...l]
      r.zadd(:compl, 0, prefix)
    end
    r.zadd(:compl,0,n+"*")
  end
else
  puts "NOT loading entries, there is already a 'compl' key\n"
end

# Complete the string "mar"

def complete(r, prefix, count)
  results = []
  rangelen = 50 # This is not random, try to get replies < MTU size
  start = r.zrank(:compl, prefix)

  return [] unless start

  while results.length != count
    range = r.zrange(:compl, start, start + rangelen - 1)
    break if range.length == 0
    range.each do |entry|
      if entry[-1..-1] == "*" and results.length != count
        results << entry[0...-1]
      end
    end
  end

  return results
end

complete(r, "mar", 10).each do |res|
  puts res
end

More Ruby-ish version.