Short: the simple url shortener

package main import ( "flag" "fmt" "log" "math/rand" "net" "net/url" "os" "regexp" "strings" "time" "github.com/gomodule/redigo/redis" "github.com/hoisie/web" ) const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" // Base strings for RandStringBytesMaskImprSrc const ( letterIdxBits = 6 // 6 bits to represent a letter index letterIdxMask = 1< Short: the simple url shortener ` const returnPage = ` Short: the simple url shortner

URL Shortened to %s

` var domain string var redisServer string var listenAddr string var proto string var path string var src = rand.NewSource(time.Now().UnixNano()) var pool = newPool() func index() string { return indexPage } func newPool() *redis.Pool { return &redis.Pool{ // Maximum number of idle connections in the pool. MaxIdle: 10, // max number of connections MaxActive: 1200, // Dial is an application supplied function for creating and // configuring a connection. Dial: func() (redis.Conn, error) { c, err := redis.Dial("tcp", redisServer) if err != nil { panic(err.Error()) } return c, err }, } } // ping tests connectivity for redis (PONG should be returned) func ping(c redis.Conn) error { // Send PING command to Redis // PING command returns a Redis "Simple String" // Use redis.String to convert the interface type to string _, err := redis.String(c.Do("PING")) if err != nil { return err } // fmt.Printf("PING Response = %s\n", s) // Output: PONG return nil } // get executes the redis GET command func get(c redis.Conn, key string) (bool, string) { s, err := redis.String(c.Do("GET", key)) if err == redis.ErrNil { return false, "" } else if err != nil { return false, "" } else { return true, s } } // set executes the redis SET command func set(c redis.Conn, url, suffix string) error { _, err := c.Do("SET", suffix, url) if err != nil { return err } return nil } func redirect(ctx *web.Context, val string) { if path != "" { val = strings.Replace(val, path, "", 1) } r, _ := regexp.Compile("[a-zA-Z0-9]+") key := r.FindString(val) conn := pool.Get() defer conn.Close() status, url := get(conn, key) if status { ctx.Redirect(302, url) } else { ctx.NotFound("URL don't exist") } } func shortner(ctx *web.Context) { _, port, _ := net.SplitHostPort(listenAddr) u, err := url.ParseRequestURI(ctx.Params["url"]) if err != nil { ctx.Abort(400, "Bad URL") } else { suffix := RandStringBytesMaskImprSrc(10) conn := pool.Get() defer conn.Close() for { status, _ := get(conn, suffix) if status { suffix = RandStringBytesMaskImprSrc(10) } else { break } } if port != "80" && proto == "http" { port = ":" + port + "/" } else if port != "443" && proto == "https" { port = ":" + port + "/" } else if port == "443" || port == "80" { port = "/" } err := set(conn, u.String(), suffix) if err != nil { ctx.Abort(500, "Internal Error") } else { shortend := proto + "://" + domain + port + path + suffix output := fmt.Sprintf(returnPage, shortend, shortend) ctx.WriteString(output) } } } // RandStringBytesMaskImprSrc Generate random string for URL func RandStringBytesMaskImprSrc(n int) string { b := make([]byte, n) // A src.Int63() generates 63 random bits, enough for letterIdxMax characters! for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; { if remain == 0 { cache, remain = src.Int63(), letterIdxMax } if idx := int(cache & letterIdxMask); idx < len(letterBytes) { b[i] = letterBytes[idx] i-- } cache >>= letterIdxBits remain-- } return string(b) } func main() { flag.StringVar(&domain, "domain", "localhost", "Domain to write to the URLs") flag.StringVar(&redisServer, "redis", "localhost:6379", "ip/hostname of the redis server to connect") flag.StringVar(&listenAddr, "addr", "localhost:8080", "Address to listen for connections") flag.StringVar(&path, "path", "", "Path to the base URL (https://localhost/PATH/... remember to append a / at the end") flag.StringVar(&proto, "proto", "https", "proto to the base URL (HTTPS://localhost/path/... no real https here just to set the url (for like a proxy offloading https") version := flag.Bool("v", false, "prints current version") flag.Parse() if *version { fmt.Printf("%s", appVersion) os.Exit(0) } if path != "" && !strings.HasSuffix(path, "/") { path = path + "/" } web.Get("/", index) web.Post("/", shortner) web.Get("/(.*)", redirect) log.Printf("Domain: %s, Redis: %s\n", domain, redisServer) web.Run(listenAddr) }