Do not do ddns update if ip is same

1 files changed, 12 insertions, 1 deletions

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,