1 files changed, 201 insertions, 0 deletions
diff --git a/modules/captcha/captcha.go b/modules/captcha/captcha.go
new file mode 100644
index 0000000000..e43e09dc59
--- /dev/null
+++ b/modules/captcha/captcha.go
@@ -0,0 +1,201 @@
+// Copyright 2014 The Gogs Authors. All rights reserved.
+// Use of this source code is governed by a MIT-style
+// license that can be found in the LICENSE file.
+
+// Package captcha a middleware that provides captcha service for Macaron.
+package captcha
+
+import (
+	"fmt"
+	"html/template"
+	"net/http"
+	"path"
+	"strings"
+
+	"github.com/Unknwon/macaron"
+
+	"github.com/gogits/cache"
+
+	"github.com/gogits/gogs/modules/base"
+	"github.com/gogits/gogs/modules/log"
+)
+
+var (
+	defaultChars = []byte{0, 1, 2, 3, 4, 5, 6, 7, 8, 9}
+)
+
+const (
+	// default captcha attributes
+	challengeNums    = 6
+	expiration       = 600
+	fieldIdName      = "captcha_id"
+	fieldCaptchaName = "captcha"
+	cachePrefix      = "captcha_"
+	defaultURLPrefix = "/captcha/"
+)
+
+// Captcha struct
+type Captcha struct {
+	store cache.Cache
+
+	// url prefix for captcha image
+	URLPrefix string
+
+	// specify captcha id input field name
+	FieldIdName string
+	// specify captcha result input field name
+	FieldCaptchaName string
+
+	// captcha image width and height
+	StdWidth  int
+	StdHeight int
+
+	// captcha chars nums
+	ChallengeNums int
+
+	// captcha expiration seconds
+	Expiration int64
+
+	// cache key prefix
+	CachePrefix string
+}
+
+// generate key string
+func (c *Captcha) key(id string) string {
+	return c.CachePrefix + id
+}
+
+// generate rand chars with default chars
+func (c *Captcha) genRandChars() []byte {
+	return base.RandomCreateBytes(c.ChallengeNums, defaultChars...)
+}
+
+// beego filter handler for serve captcha image
+func (c *Captcha) Handler(ctx *macaron.Context) {
+	var chars []byte
+
+	id := path.Base(ctx.Req.RequestURI)
+	if i := strings.Index(id, "."); i != -1 {
+		id = id[:i]
+	}
+
+	key := c.key(id)
+
+	if v, ok := c.store.Get(key).([]byte); ok {
+		chars = v
+	} else {
+		ctx.Status(404)
+		ctx.Write([]byte("captcha not found"))
+		return
+	}
+
+	// reload captcha
+	if len(ctx.Query("reload")) > 0 {
+		chars = c.genRandChars()
+		if err := c.store.Put(key, chars, c.Expiration); err != nil {
+			ctx.Status(500)
+			ctx.Write([]byte("captcha reload error"))
+			log.Error(4, "Reload Create Captcha Error: %v", err)
+			return
+		}
+	}
+
+	img := NewImage(chars, c.StdWidth, c.StdHeight)
+	if _, err := img.WriteTo(ctx.RW()); err != nil {
+		log.Error(4, "Write Captcha Image Error: %v", err)
+	}
+}
+
+// tempalte func for output html
+func (c *Captcha) CreateCaptchaHtml() template.HTML {
+	value, err := c.CreateCaptcha()
+	if err != nil {
+		log.Error(4, "Create Captcha Error: %v", err)
+		return ""
+	}
+
+	// create html
+	return template.HTML(fmt.Sprintf(`<input type="hidden" name="%s" value="%s">`+
+		`<a class="captcha" href="javascript:">`+
+		`<img onclick="this.src=('%s%s.png?reload='+(new Date()).getTime())" class="captcha-img" src="%s%s.png">`+
+		`</a>`, c.FieldIdName, value, c.URLPrefix, value, c.URLPrefix, value))
+}
+
+// create a new captcha id
+func (c *Captcha) CreateCaptcha() (string, error) {
+	// generate captcha id
+	id := string(base.RandomCreateBytes(15))
+
+	// get the captcha chars
+	chars := c.genRandChars()
+
+	// save to store
+	if err := c.store.Put(c.key(id), chars, c.Expiration); err != nil {
+		return "", err
+	}
+
+	return id, nil
+}
+
+// verify from a request
+func (c *Captcha) VerifyReq(req *http.Request) bool {
+	req.ParseForm()
+	return c.Verify(req.Form.Get(c.FieldIdName), req.Form.Get(c.FieldCaptchaName))
+}
+
+// direct verify id and challenge string
+func (c *Captcha) Verify(id string, challenge string) (success bool) {
+	if len(challenge) == 0 || len(id) == 0 {
+		return
+	}
+
+	var chars []byte
+
+	key := c.key(id)
+
+	if v, ok := c.store.Get(key).([]byte); ok && len(v) == len(challenge) {
+		chars = v
+	} else {
+		return
+	}
+
+	defer func() {
+		// finally remove it
+		c.store.Delete(key)
+	}()
+
+	// verify challenge
+	for i, c := range chars {
+		if c != challenge[i]-48 {
+			return
+		}
+	}
+
+	return true
+}
+
+// create a new captcha.Captcha
+func NewCaptcha(urlPrefix string, store cache.Cache) *Captcha {
+	cpt := &Captcha{}
+	cpt.store = store
+	cpt.FieldIdName = fieldIdName
+	cpt.FieldCaptchaName = fieldCaptchaName
+	cpt.ChallengeNums = challengeNums
+	cpt.Expiration = expiration
+	cpt.CachePrefix = cachePrefix
+	cpt.StdWidth = stdWidth
+	cpt.StdHeight = stdHeight
+
+	if len(urlPrefix) == 0 {
+		urlPrefix = defaultURLPrefix
+	}
+
+	if urlPrefix[len(urlPrefix)-1] != '/' {
+		urlPrefix += "/"
+	}
+
+	cpt.URLPrefix = urlPrefix
+
+	base.TemplateFuncs["CreateCaptcha"] = cpt.CreateCaptchaHtml
+	return cpt
+}