example/main.go (view raw)
1// example of HTTP server that uses the captcha package.
2package main
3
4import (
5 "fmt"
6 "github.com/dchest/captcha"
7 "http"
8 "io"
9 "log"
10 "template"
11)
12
13var formTemplate = template.MustParse(formTemplateSrc, nil)
14
15func showFormHandler(w http.ResponseWriter, r *http.Request) {
16 if r.URL.Path != "/" {
17 http.NotFound(w, r)
18 return
19 }
20 d := struct {
21 CaptchaId string
22 JavaScript string
23 }{
24 captcha.New(captcha.StdLength),
25 formJavaScript,
26 }
27 if err := formTemplate.Execute(w, &d); err != nil {
28 http.Error(w, err.String(), http.StatusInternalServerError)
29 }
30}
31
32func processFormHandler(w http.ResponseWriter, r *http.Request) {
33 if !captcha.VerifyString(r.FormValue("captchaId"), r.FormValue("captchaSolution")) {
34 io.WriteString(w, "Wrong captcha solution! No robots allowed!\n")
35 } else {
36 io.WriteString(w, "Great job, human! You solved the captcha.\n")
37 }
38 io.WriteString(w, "<br><a href='/'>Try another one</a>")
39}
40
41func main() {
42 http.HandleFunc("/", showFormHandler)
43 http.HandleFunc("/process", processFormHandler)
44 http.Handle("/captcha/", captcha.Server(captcha.StdWidth, captcha.StdHeight))
45 fmt.Println("Server is at localhost:8666")
46 if err := http.ListenAndServe(":8666", nil); err != nil {
47 log.Fatal(err)
48 }
49}
50
51const formJavaScript = `
52function playAudio() {
53 var e = document.getElementById('audio')
54 e.style.display = 'block';
55 e.play();
56 return false;
57}
58
59function reload() {
60 function setSrcQuery(e, q) {
61 var src = e.src;
62 var p = src.indexOf('?');
63 if (p >= 0) {
64 src = src.substr(0, p);
65 }
66 e.src = src + "?" + q
67 }
68 setSrcQuery(document.getElementById('image'), "reload=" + (new Date()).getTime());
69 setSrcQuery(document.getElementById('audio'), (new Date()).getTime());
70 return false;
71}
72`
73
74const formTemplateSrc = `<!doctype html>
75<head><title>Captcha Example</title></head>
76<body>
77<script>
78{JavaScript}
79</script>
80<form action="/process" method=post>
81<p>Type the numbers you see in the picture below:</p>
82<p><img id=image src="/captcha/{CaptchaId}.png" alt="Captcha image"></p>
83<a href="#" onclick="reload()">Reload</a> | <a href="#" onclick="playAudio()">Play Audio</a>
84<audio id=audio controls style="display:none" src="/captcha/{CaptchaId}.wav" preload=none>
85 You browser doesn't support audio.
86 <a href="/captcha/download/{CaptchaId}.wav">Download file</a> to play it in the external player.
87</audio>
88<input type=hidden name=captchaId value="{CaptchaId}"><br>
89<input name=captchaSolution>
90<input type=submit value=Submit>
91</form>
92`