Implementing signed links for email message

internal/urlsigner/signer.go

@@ -0,0 +1,44 @@
+package urlsigner
+
+import (
+	"fmt"
+	"strings"
+	"time"
+
+	goalone "github.com/bwmarrin/go-alone"
+)
+
+type Signer struct {
+	Secret []byte
+}
+
+func (s *Signer) GenerateTokenFromString(data string) string {
+	var urlToSign string
+
+	crypt := goalone.New(s.Secret, goalone.Timestamp)
+	if strings.Contains(data, "?") {
+		urlToSign = fmt.Sprintf("%s&hash=", data)
+	} else {
+		urlToSign = fmt.Sprintf("%s?hash=", data)
+	}
+
+	tokenBytes := crypt.Sign([]byte(urlToSign))
+	token := string(tokenBytes)
+	return token
+}
+
+func (s *Signer) VerifyToken(token string) bool {
+	crypt := goalone.New(s.Secret, goalone.Timestamp)
+	_, err := crypt.Unsign([]byte(token))
+	if err != nil {
+		fmt.Println(err)
+	}
+	return true
+}
+
+func (s *Signer) Expired(token string, minutesUntilExpire int) bool {
+	crypt := goalone.New(s.Secret, goalone.Timestamp)
+	ts := crypt.Parse([]byte(token))
+
+	return time.Since(ts.Timestamp) > time.Duration(minutesUntilExpire)*time.Minute
+}