From d8eece90463dc0396e2390227503aa909c4e80ad Mon Sep 17 00:00:00 2001
From: Joerg Lehmann <joerg.lehmann@nbit.ch>
Date: Sun, 2 Oct 2022 16:07:31 +0200
Subject: [PATCH] update user only if it exists

---
 persistence.go | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/persistence.go b/persistence.go
index 9c9e4df..e8827f1 100644
--- a/persistence.go
+++ b/persistence.go
@@ -362,6 +362,14 @@ func updateUser(username, password string) {
 	conn := globalPool.Get()
 	defer conn.Close()
 	logit("updateUser: " + username)
+
+        // we exit if user does not exit
+	exists, _ := redis.Bool(conn.Do("EXISTS", userPrefix+username))
+	if !exists {
+	        logit("updateUser: User does not exist: " + username)
+		return
+	}
+
 	pwd := []byte(password)
 	hashedPassword, err := bcrypt.GenerateFromPassword(pwd, bcrypt.DefaultCost)
 	if err != nil {