From 52eb9dc9fc1e0472aea4fd5bd0bb7ea259431d41 Mon Sep 17 00:00:00 2001
From: Mike Crute <mike@crute.us>
Date: Tue, 11 Aug 2020 05:11:29 +0000
Subject: Do not do ddns update if ip is same

---
 web/controllers/ddns.go | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

(limited to 'web')

diff --git a/web/controllers/ddns.go b/web/controllers/ddns.go
index 692b59f..d476255 100644
--- a/web/controllers/ddns.go
+++ b/web/controllers/ddns.go
@@ -5,6 +5,7 @@ import (
 	"net/http"
 
 	"github.com/gin-gonic/gin"
+	godns "github.com/miekg/dns"
 
 	"code.crute.me/mcrute/go_ddns_manager/dns"
 	"code.crute.me/mcrute/go_ddns_manager/util"
@@ -35,7 +36,17 @@ func UpdateDynamicDNS(c *gin.Context) {
 		return
 	}
 
-	txn := cfg.DNSClient.StartUpdate(zone).Upsert(&dns.A{
+	txn := cfg.DNSClient.QueryRecursive(zone, res, godns.TypeA)
+	cur, err := cfg.DNSClient.SendQuery(txn)
+	if err == nil && len(cur) == 1 {
+		if cur[0].(*godns.A).A.Equal(inip) {
+			log.Printf("ddns: Update not required for '%s', IP %s", res, inip)
+			c.String(http.StatusNotModified, "")
+			return
+		}
+	}
+
+	txn = cfg.DNSClient.StartUpdate(zone).Upsert(&dns.A{
 		Name: part,
 		Ttl:  60,
 		A:    inip,
-- 
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