190 lines
4.3 KiB
Go
190 lines
4.3 KiB
Go
package main
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import (
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"flag"
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"fmt"
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"log"
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"math/rand"
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"net"
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"net/url"
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"os"
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"regexp"
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"strings"
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"time"
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"github.com/hoisie/web"
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"github.com/patrickmn/go-cache"
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)
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const letterBytes = "abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ0123456789" // Base strings for RandStringBytesMaskImprSrc
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const (
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letterIdxBits = 6 // 6 bits to represent a letter index
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letterIdxMask = 1<<letterIdxBits - 1 // All 1-bits, as many as letterIdxBits
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letterIdxMax = 63 / letterIdxBits // # of letter indices fitting in 63 bits
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)
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const (
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appVersion = "0.1.0"
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)
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const indexPage = `
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<!DOCTYPE html>
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<html lang=en>
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<head>
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<title>Short: the simple url shortener</title>
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<style>
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form{
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position:fixed;
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top:30%;
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left:40%;
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width:500px;
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font-family:georgia,garamond,serif;
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font-size:16px;
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}
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</style>
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</head>
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<body>
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<form action="/" method="POST">
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<label for="url">
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Please type the url</label>
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<br>
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<input id="url" type="text" name="url"/>
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<input type="submit" name="Submit" value="Submit"/>
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</form>
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</body>
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</html>
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`
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const returnPage = `
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<!DOCTYPE html>
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<html lang=en>
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<head>
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<title>Short: the simple url shortner</title>
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<style>
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.center {
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padding: 70px 0;
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border: none;
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border-color: transparent;
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text-align: center;
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font-family:georgia,garamond,serif;
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font-size:16px;
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}
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</style>
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</head>
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<body>
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<div class="center">
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URL Shortened to <a href="%s">%s</a>
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</div>
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</body>
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</html>
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`
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var domain string
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var redisServer string
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var listenAddr string
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var proto string
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var path string
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var src = rand.NewSource(time.Now().UnixNano())
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var pool = cache.New(240*time.Hour, 1*time.Hour)
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func index() string { return indexPage }
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// get executes the GET command
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func get(key string) (string, bool) {
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value, status := pool.Get(key)
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if status {
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return value.(string), status
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}
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return "", false
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}
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// set executes the redis SET command
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func set(url, suffix string) {
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pool.Set(suffix, url, 0)
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}
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func redirect(ctx *web.Context, val string) {
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if path != "" {
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val = strings.Replace(val, path, "", 1)
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}
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r, _ := regexp.Compile("[a-zA-Z0-9]+")
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key := r.FindString(val)
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url, status := get(key)
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fmt.Println(url)
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if status {
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ctx.Redirect(302, url)
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} else {
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ctx.NotFound("URL don't exist")
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}
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}
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func shortner(ctx *web.Context) {
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_, port, _ := net.SplitHostPort(listenAddr)
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u, err := url.ParseRequestURI(ctx.Params["url"])
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if err != nil {
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ctx.Abort(400, "Bad URL")
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} else {
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suffix := RandStringBytesMaskImprSrc(10)
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for {
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_, status := get(suffix)
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if status {
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suffix = RandStringBytesMaskImprSrc(10)
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} else {
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break
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}
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}
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if port != "80" && proto == "http" {
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port = ":" + port + "/"
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} else if port != "443" && proto == "https" {
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port = ":" + port + "/"
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} else if port == "443" || port == "80" {
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port = "/"
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}
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set(u.String(), suffix)
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shortend := proto + "://" + domain + port + path + suffix
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output := fmt.Sprintf(returnPage, shortend, shortend)
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ctx.WriteString(output)
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}
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}
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// RandStringBytesMaskImprSrc Generate random string for URL
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func RandStringBytesMaskImprSrc(n int) string {
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b := make([]byte, n)
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// A src.Int63() generates 63 random bits, enough for letterIdxMax characters!
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for i, cache, remain := n-1, src.Int63(), letterIdxMax; i >= 0; {
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if remain == 0 {
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cache, remain = src.Int63(), letterIdxMax
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}
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if idx := int(cache & letterIdxMask); idx < len(letterBytes) {
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b[i] = letterBytes[idx]
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i--
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}
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cache >>= letterIdxBits
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remain--
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}
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return string(b)
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}
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func main() {
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flag.StringVar(&domain, "domain", "localhost", "Domain to write to the URLs")
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flag.StringVar(&listenAddr, "addr", "localhost:8080", "Address to listen for connections")
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flag.StringVar(&path, "path", "", "Path to the base URL (https://localhost/PATH/... remember to append a / at the end")
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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")
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version := flag.Bool("v", false, "prints current version")
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flag.Parse()
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if *version {
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fmt.Printf("%s", appVersion)
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os.Exit(0)
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}
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if path != "" && !strings.HasSuffix(path, "/") {
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path = path + "/"
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}
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web.Get("/", index)
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web.Post("/", shortner)
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web.Get("/(.*)", redirect)
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log.Printf("Domain: %s, URL Proto: %s\n", domain, proto)
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web.Run(listenAddr)
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}
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