Short: the simple url shortener

package main import ( "flag" "fmt" "log" "math/rand" "net/http" "net/url" "os" "regexp" "strings" "time" "github.com/gorilla/handlers" "github.com/gorilla/mux" "github.com/patrickmn/go-cache" ) 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 = cache.New(240*time.Hour, 1*time.Hour) func index(w http.ResponseWriter, r *http.Request) { w.Write([]byte(indexPage)) } // get executes the GET command func get(key string) (string, bool) { value, status := pool.Get(key) if status { return value.(string), status } return "", false } // set executes the redis SET command func set(url, suffix string) { pool.Set(suffix, url, 0) } func redirect(w http.ResponseWriter, r *http.Request) { vals := mux.Vars(r) val := vals["key"] if path != "" { val = strings.Replace(val, path, "", 1) } rgx, _ := regexp.Compile("[a-zA-Z0-9]+") key := rgx.FindString(val) url, status := get(key) if status { http.Redirect(w, r, url, http.StatusFound) } else { w.WriteHeader(http.StatusNotFound) w.Write([]byte("URL don't exist")) } } func shortner(w http.ResponseWriter, r *http.Request) { u, err := url.ParseRequestURI(r.FormValue("url")) if err != nil { w.WriteHeader(http.StatusBadRequest) w.Write([]byte("Bad URL")) } else { suffix := RandStringBytesMaskImprSrc(10) for { _, status := get(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 = "/" } set(u.String(), suffix) shortend := proto + "://" + domain + port + path + suffix output := fmt.Sprintf(returnPage, shortend, shortend) w.Write([]byte(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(&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 + "/" } r := mux.NewRouter() r.HandleFunc("/", index).Methods("GET") r.HandleFunc("/", shortner).Methods("POST") r.HandleFunc("/{key}", redirect).Methods("GET") log.Printf("Domain: %s, URL Proto: %s\n", domain, proto) log.Fatal(http.ListenAndServe(listenAddr, handlers.CombinedLoggingHandler(os.Stdout, r))) }