// generateRandomKey creates a random key with the given strength.
func generateRandomKey(strength int) []byte {
k := make([]byte, strength)
if n, err := io.ReadFull(rand.Reader, k); n != strength || err != nil {
return utils.RandomCreateBytes(strength)
}
return k
}
func BenchmarkNewImage(b *testing.B) {
b.StopTimer()
d := utils.RandomCreateBytes(challengeNums, defaultChars...)
b.StartTimer()
for i := 0; i < b.N; i++ {
NewImage(d, stdWidth, stdHeight)
}
}
// XsrfToken creates a xsrf token string and returns.
func (ctx *Context) XsrfToken(key string, expire int64) string {
if ctx._xsrf_token == "" {
token, ok := ctx.GetSecureCookie(key, "_xsrf")
if !ok {
token = string(utils.RandomCreateBytes(32))
ctx.SetSecureCookie(key, "_xsrf", token, expire)
}
ctx._xsrf_token = token
}
return ctx._xsrf_token
}
func BenchmarkImageWriteTo(b *testing.B) {
b.StopTimer()
d := utils.RandomCreateBytes(challengeNums, defaultChars...)
b.StartTimer()
counter := &byteCounter{}
for i := 0; i < b.N; i++ {
img := NewImage(d, stdWidth, stdHeight)
img.WriteTo(counter)
b.SetBytes(counter.n)
counter.n = 0
}
}
// create a new captcha id
func (c *Captcha) CreateCaptcha() (string, error) {
// generate captcha id
id := string(utils.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
}
// generate session id with rand string, unix nano time, remote addr by hash function.
func (manager *Manager) sessionId(r *http.Request) (sid string) {
bs := make([]byte, 32)
if n, err := io.ReadFull(rand.Reader, bs); n != 32 || err != nil {
bs = utils.RandomCreateBytes(32)
}
sig := fmt.Sprintf("%s%d%s", r.RemoteAddr, time.Now().UnixNano(), bs)
if manager.config.SessionIDHashFunc == "md5" {
h := md5.New()
h.Write([]byte(sig))
sid = hex.EncodeToString(h.Sum(nil))
} else if manager.config.SessionIDHashFunc == "sha1" {
h := hmac.New(sha1.New, []byte(manager.config.SessionIDHashKey))
fmt.Fprintf(h, "%s", sig)
sid = hex.EncodeToString(h.Sum(nil))
} else {
h := hmac.New(sha1.New, []byte(manager.config.SessionIDHashKey))
fmt.Fprintf(h, "%s", sig)
sid = hex.EncodeToString(h.Sum(nil))
}
return
}
// generate rand chars with default chars
func (c *Captcha) genRandChars() []byte {
return utils.RandomCreateBytes(c.ChallengeNums, defaultChars...)
}