Implement specify Port for DNS Monitor #1059

This commit should fully implement #1059. When the user selects the DNS
monitor option, a new input box has been added below the resolver
address allowing the user to implement the port to access the resolver
on. This uses the same `monitor.port` as the TCP monitor but a monitor
has been added to prefill the port value to the default of `53` if the
value in this field has not already been set. This is then cleared if
the user selects a different monitor type and has not changed the port
value. A translation has also been added explaining what this field
does in order to reduce any confusion. JSDoc documentation has also been
added to the `dnsResolve` function in `util-server.js`.

Signed-off-by: Matthew Nickson <mnickson@sidingsmedia.com>

server/model/monitor.js

@@ -249,7 +249,7 @@ class Monitor extends BeanModel {
                     let startTime = dayjs().valueOf();
                     let dnsMessage = "";
 
-                    let dnsRes = await dnsResolve(this.hostname, this.dns_resolve_server, this.dns_resolve_type);
+                    let dnsRes = await dnsResolve(this.hostname, this.dns_resolve_server, this.port, this.dns_resolve_type);
                     bean.ping = dayjs().valueOf() - startTime;
 
                     if (this.dns_resolve_type == "A" || this.dns_resolve_type == "AAAA" || this.dns_resolve_type == "TXT") {

server/util-server.js

@@ -89,9 +89,17 @@ exports.pingAsync = function (hostname, ipv6 = false) {
     });
 };
 
-exports.dnsResolve = function (hostname, resolver_server, rrtype) {
+/**
+ * Resolves a given record using the specified DNS server
+ * @param {string} hostname The hostname of the record to lookup
+ * @param {string} resolver_server The DNS server to use
+ * @param {string} resolver_port The port the DNS server is listening on
+ * @param {string} rrtype The type of record to request
+ * @returns {Promise} Promise object represents DNS lookup result
+ */
+exports.dnsResolve = function (hostname, resolver_server, resolver_port, rrtype) {
     const resolver = new Resolver();
-    resolver.setServers([resolver_server]);
+    resolver.setServers([`${resolver_server}:${resolver_port}`]);
     return new Promise((resolve, reject) => {
         if (rrtype == "PTR") {
             resolver.reverse(hostname, (err, records) => {

src/languages/en.js

@@ -14,6 +14,7 @@ export default {
     deleteMonitorMsg: "Are you sure want to delete this monitor?",
     deleteNotificationMsg: "Are you sure want to delete this notification for all monitors?",
     resoverserverDescription: "Cloudflare is the default server. You can change the resolver server anytime.",
+    dnsPortDescription: "DNS server port. Defaults to 53. You can change the port at any time.",
     rrtypeDescription: "Select the RR type you want to monitor",
     pauseMonitorMsg: "Are you sure want to pause?",
     enableDefaultNotificationDescription: "This notification will be enabled by default for new monitors. You can still disable the notification separately for each monitor.",

src/pages/EditMonitor.vue

@@ -91,6 +91,15 @@
                                     </div>
                                 </div>
 
+                                <!-- Port -->
+                                <div class="my-3">
+                                    <label for="port" class="form-label">{{ $t("Port") }}</label>
+                                    <input id="port" v-model="monitor.port" type="number" class="form-control" required min="0" max="65535" step="1">
+                                    <div class="form-text">
+                                        {{ $t("dnsPortDescription") }}
+                                    </div>
+                                </div>
+
                                 <div class="my-3">
                                     <label for="dns_resolve_type" class="form-label">{{ $t("Resource Record Type") }}</label>
 
@@ -386,6 +395,15 @@ export default {
                     this.monitor.pushToken = genSecret(10);
                 }
             }
+
+            // Set default port for DNS if not already defined
+            if (! this.monitor.port || this.monitor.port === "53") {
+                if (this.monitor.type === "dns") {
+                    this.monitor.port = "53";
+                } else {
+                    this.monitor.port = "";
+                }
+            }
         }
 
     },