Autocomplete using Redis backend. Handles UTF8 strings. See this blog post on how to load the Redis data http://oldblog.antirez.com/post/autocomplete-with-redis.html

autocomplete.go

import (
	"strings"

	u8 "code.google.com/p/go.exp/utf8string"
	"github.com/garyburd/redigo/redis"
)

// Based on code by Salvatore Sanfilippo
// http://oldblog.antirez.com/post/autocomplete-with-redis.html
func RedisComplete(prefix string, count int) (results []string, err error) {

	prefix = strings.Title(prefix)

	rangelen := 50
	start := 0
	u8p := u8.NewString(prefix)

	start, rerr := redis.Int(redisConn.Do("ZRANK", "compl", prefix))
	if rerr != nil {
		if rerr == redis.ErrNil {
			return
		}
		return nil, rerr
	}

	for len(results) != count {

		var rerr error
		var elements []string

		elements, rerr = redis.Strings(redisConn.Do("ZRANGE", "compl", start, start+rangelen-1))
		if rerr != nil {
			if rerr == redis.ErrNil {
				break
			}
			return nil, rerr
		}

		start += rangelen
		if len(elements) == 0 {
			break
		}

		for _, v := range elements {
			u8v := u8.NewString(v)
                        var minlen int 
                        if u8v.RuneCount() <= u8p.RuneCount() {
                                minlen = u8v.RuneCount()
                        } else {
                                minlen = u8p.RuneCount()
                        }

			if u8v.Slice(0, minlen) != u8p.Slice(0, minlen) {
				count = len(results)
				break
			}

			if u8v.At(u8v.RuneCount()-1) == '*' {
				results = append(results, strings.TrimRight(v, "*"))
				if len(results) == count {
					break
				}
			}
		}
	}
	return
}