Add URL parameter to enable notification of IP changes

README.md

@@ -166,6 +166,7 @@ Without TSIG authentication, the DNS server must allow updates based on IP addre
 ### Endpoints
 
 Configure one or more HTTP endpoints. If no endpoints are defined, a default endpoint at `/update` is created with standard parameter names.
+Set an empty list of names to disable a parameter.
 
 ```toml
 [[endpoints]]
@@ -176,6 +177,7 @@ ipv4 = ["myip", "ipv4", "ip4"]
 ipv6 = ["myip6", "ipv6", "ip6"]
 username = ["username", "user"]
 password = ["password", "pass", "token"]
+notify_change = ["notify_change"]
 
 [[endpoints]]
 path = "/nic/update"
@@ -185,6 +187,7 @@ ipv4 = ["myip"]
 ipv6 = ["myip6"]
 username = ["username"]
 password = ["password"]
+notify_change = []
 ```
 
 **Default accepted parameter names** (first match wins):

files/config.example.toml

@@ -65,7 +65,10 @@ from_address = "ddns@example.com"  # required if email.enabled
 #   ipv6 (IPv6 address): myip6, ipv6, ip6
 #   username: username, user
 #   password: password, pass, token
+#   notify_change: notify_change
+#
 # Multiple endpoints can be defined with custom parameter names
+
 # [[endpoints]]
 # path = "/update"
 # [endpoints.params]
@@ -74,6 +77,7 @@ from_address = "ddns@example.com"  # required if email.enabled
 # ipv6 = ["myip6", "ipv6", "ip6"]
 # username = ["username", "user"]
 # password = ["password", "pass", "token"]
+# notify_change = ["notify_change"]
 
 # [[endpoints]]
 # path = "/nic/update"
@@ -83,3 +87,4 @@ from_address = "ddns@example.com"  # required if email.enabled
 # ipv6 = ["myip6"]
 # username = ["username"]
 # password = ["password"]
+# notify_change = []

src/ddns_service/cli.py

@@ -149,7 +149,7 @@ def cmd_hostname_list(args, app):
         return 0
 
     print(
-        f"{'Hostname':<35} {'User':<15} {'Zone':<20} "
+        f"\n{'Hostname':<35} {'User':<15} {'Zone':<20} "
         f"{'DNS-TTL':<8} {'Exp-TTL':<8} {'Last-Update IPv4':<25} {'Last-Update IPv6'}"
     )
     print("-" * 140)

src/ddns_service/config.py

@@ -21,6 +21,7 @@ DEFAULT_ENDPOINT_PARAMS = {
     "ipv6": ["myip6", "ipv6", "ip6"],
     "username": ["username", "user"],
     "password": ["password", "pass", "token"],
+    "notify_change": ["notify_change"],
 }
 
 VALID_PARAM_KEYS = frozenset(DEFAULT_ENDPOINT_PARAMS.keys())

src/ddns_service/email.py

@@ -94,7 +94,7 @@ class EmailService:
             logging.error(f"Email send failed: to={to} error={e}")
             return False
 
-    def send_changed_notification(
+    def send_change_notification(
         self,
         email,
         hostname,
@@ -135,8 +135,8 @@ class EmailService:
             "expiry_ttl": hostname.expiry_ttl,
         }
 
-        subject = f"DDNS hostname expired: {fqdn}"
-        body = self.expiry_template.render(**template_variables)
+        subject = f"DDNS hostname changed: {fqdn}"
+        body = self.change_template.render(**template_variables)
 
         return self.send(email, subject, body)
 

src/ddns_service/server.py

@@ -317,7 +317,8 @@ class DDNSRequestHandler(BaseHTTPRequestHandler):
 
         now = utc_now()
 
-        changed = False
+        ipv4_changed = False
+        ipv6_changed = False
         if ipv4:
             hostname.last_ipv4_update = now
             if ipv4 != hostname.last_ipv4:
@@ -330,7 +331,7 @@ class DDNSRequestHandler(BaseHTTPRequestHandler):
                         hostname.dns_ttl
                     )
                     hostname.last_ipv4 = ipv4
-                    changed = True
+                    ipv4_changed = True
                 except Exception as e:
                     hostname.save()
                     logging.error(
@@ -351,7 +352,7 @@ class DDNSRequestHandler(BaseHTTPRequestHandler):
                         hostname.dns_ttl
                     )
                     hostname.last_ipv6 = ipv6
-                    changed = True
+                    ipv6_changed = True
                 except Exception as e:
                     hostname.save()
                     logging.error(
@@ -364,15 +365,15 @@ class DDNSRequestHandler(BaseHTTPRequestHandler):
         hostname.save()
 
         changed_addrs = ""
-        if ipv4:
-            changed_addrs += f"ipv4={ipv4}"
-        if ipv6:
+        if ipv4_changed:
+            changed_addrs += f" ipv4={ipv4}"
+        if ipv6_changed:
             changed_addrs += f" ipv6={ipv6}"
 
-        if not changed:
+        if not ipv4_changed and not ipv6_changed:
             logging.info(
                 f"No change: client={client_ip} hostname={hostname.hostname} "
-                f"zone={hostname.zone} {changed_addrs}"
+                f"zone={hostname.zone}{changed_addrs}"
             )
             return (
                 200, "nochg",
@@ -381,8 +382,21 @@ class DDNSRequestHandler(BaseHTTPRequestHandler):
 
         logging.info(
             f"Updated: client={client_ip} hostname={hostname.hostname} "
-            f"zone={hostname.zone} {changed_addrs}"
+            f"zone={hostname.zone}{changed_addrs}"
         )
+
+        notify_change = extract_param(params, endpoint["params"]["notify_change"])
+        if notify_change and notify_change.lower() not in ["0", "no", "off"]:
+            try:
+                self.app.email_service.send_change_notification(
+                    hostname.user.email,
+                    hostname,
+                    ipv4_changed,
+                    ipv6_changed
+                )
+            except Exception as e:
+                logging.error(f"Sending change notification error: {e}")
+
         return (
             200, "good",
             {"ipv4": hostname.last_ipv4, "ipv6": hostname.last_ipv6}