example/main.go (view raw)
1// example of HTTP server that uses the captcha package.
2package main
3
4import (
5 "github.com/dchest/captcha"
6 "http"
7 "io"
8 "log"
9 "template"
10)
11
12var formTemplate = template.MustParse(formTemplateSrc, nil)
13
14func showFormHandler(w http.ResponseWriter, r *http.Request) {
15 if r.URL.Path != "/" {
16 http.NotFound(w, r)
17 return
18 }
19 d := struct {
20 CaptchaId string
21 JavaScript string
22 }{
23 captcha.New(captcha.StdLength),
24 formJavaScript,
25 }
26 if err := formTemplate.Execute(w, &d); err != nil {
27 http.Error(w, err.String(), http.StatusInternalServerError)
28 }
29}
30
31func processFormHandler(w http.ResponseWriter, r *http.Request) {
32 if !captcha.VerifyString(r.FormValue("captchaId"), r.FormValue("captchaSolution")) {
33 io.WriteString(w, "Wrong captcha solution! No robots allowed!\n")
34 } else {
35 io.WriteString(w, "Great job, human! You solved the captcha.\n")
36 }
37 io.WriteString(w, "<br><a href='/'>Try another one</a>")
38}
39
40func main() {
41 http.HandleFunc("/", showFormHandler)
42 http.HandleFunc("/process", processFormHandler)
43 http.Handle("/captcha/", captcha.Server(captcha.StdWidth, captcha.StdHeight))
44 if err := http.ListenAndServe(":8080", nil); err != nil {
45 log.Fatal(err)
46 }
47}
48
49const formJavaScript = `
50function playAudio() {
51 var e = document.getElementById('audio')
52 e.style.display = 'block';
53 e.play();
54 return false;
55}
56
57function reload() {
58 function setSrcQuery(e, q) {
59 var src = e.src;
60 var p = src.indexOf('?');
61 if (p >= 0) {
62 src = src.substr(0, p);
63 }
64 e.src = src + "?" + q
65 }
66 setSrcQuery(document.getElementById('image'), "reload=" + (new Date()).getTime());
67 setSrcQuery(document.getElementById('audio'), (new Date()).getTime());
68 return false;
69}
70`
71
72const formTemplateSrc = `<!doctype html>
73<head><title>Captcha Example</title></head>
74<body>
75<script>
76{JavaScript}
77</script>
78<form action="/process" method=post>
79<p>Type the numbers you see in the picture below:</p>
80<p><img id=image src="/captcha/{CaptchaId}.png" alt="Captcha image"></p>
81<a href="#" onclick="reload()">Reload</a> | <a href="#" onclick="playAudio()">Play Audio</a>
82<audio id=audio controls style="display:none" src="/captcha/{CaptchaId}.wav" preload=none>
83 You browser doesn't support audio.
84 <a href="/captcha/download/{CaptchaId}.wav">Download file</a> to play it in the external player.
85</audio>
86<input type=hidden name=captchaId value="{CaptchaId}"><br>
87<input name=captchaSolution>
88<input type=submit value=Submit>
89</form>
90`