added totp support

pkg/otp/otp.go

@@ -0,0 +1,72 @@
+// Copyright (C) 2018 Marius Schellenberger
+
+package otp
+
+import (
+	"bytes"
+	"encoding/base64"
+	"github.com/pquerna/otp"
+	"github.com/pquerna/otp/totp"
+	"html/template"
+	"image/png"
+)
+
+const dataUrl = "data:image/png;base64,"
+
+func base64Image(key *otp.Key) (data template.URL, err error) {
+	var buf bytes.Buffer
+	img, err := key.Image(200, 200)
+	if err != nil {
+		return
+	}
+	err = png.Encode(&buf, img)
+	if err != nil {
+		return
+	}
+	data = template.URL(dataUrl + base64.StdEncoding.EncodeToString(buf.Bytes()))
+	return
+}
+
+type Request struct {
+	Username string
+	Image    template.URL
+	Secret   string
+	URL      string
+}
+
+func New(username string) (req Request, err error) {
+	key, err := totp.Generate(totp.GenerateOpts{
+		Issuer:      "gowiki",
+		AccountName: username,
+	})
+	if err != nil {
+		return
+	}
+	data, err := base64Image(key)
+	if err != nil {
+		return
+	}
+	return Request{
+		Username: username,
+		Image:    data,
+		Secret:   key.Secret(),
+		URL:      key.URL(),
+	}, nil
+}
+
+func Validate(pin, secret string) bool {
+	if secret == "" {
+		return true
+	}
+	return totp.Validate(pin, secret)
+}
+
+func ImageSecretFromURL(url string) (data template.URL, secret string, err error) {
+	key, err := otp.NewKeyFromURL(url)
+	if err != nil {
+		return
+	}
+	secret = key.Secret()
+	data, err = base64Image(key)
+	return
+}