issue #85: added native IP resolution for Android, macOS and iOS

sebastianhaberey · sebastianhaberey · commit 663661312e29 · 2025-12-23T10:09:28.000+01:00
- added native macOS IP addresses (inspired by #83) - extended example app to display multiple addresses (taken from #84) - extended Android side to use new getHostAddresses instead of deprecate host (since API 34) - Android side now always returns multiple addresses - IpLookupType functionality internally uses natively supplied addresses (if available) - added filtering of addresses for IpLookupType to maintain exisiting behavior
diff --git a/nsd/example/lib/main.dart b/nsd/example/lib/main.dart
@@ -1,5 +1,6 @@
 import 'dart:async';
 import 'dart:convert';
+import 'dart:io';
 import 'dart:typed_data';
 
 import 'package:flutter/material.dart';
@@ -178,22 +179,24 @@ class DiscoveryState extends State<DiscoveryWidget> {
 
   Widget buildDataTable(
       BuildContext context, Discovery discovery, Widget? child) {
-    return DataTable(
-      headingRowHeight: 24,
-      dataRowMinHeight: 24,
-      dataRowMaxHeight: 24,
-      dataTextStyle: const TextStyle(color: Colors.black, fontSize: 12),
-      columnSpacing: 8,
-      horizontalMargin: 0,
-      headingTextStyle: const TextStyle(
-          color: Colors.black, fontSize: 12, fontWeight: FontWeight.w600),
-      columns: <DataColumn>[
-        buildDataColumn('Name'),
-        buildDataColumn('Type'),
-        buildDataColumn('Host'),
-        buildDataColumn('Port'),
-      ],
-      rows: buildDataRows(discovery),
+    return SingleChildScrollView(
+      scrollDirection: Axis.horizontal,
+      child: DataTable(
+        dataRowMinHeight: 24,
+        dataTextStyle: const TextStyle(color: Colors.black, fontSize: 12),
+        columnSpacing: 8,
+        horizontalMargin: 0,
+        headingTextStyle: const TextStyle(
+            color: Colors.black, fontSize: 12, fontWeight: FontWeight.w600),
+        columns: <DataColumn>[
+          buildDataColumn('Name'),
+          buildDataColumn('Type'),
+          buildDataColumn('Host'),
+          buildDataColumn('Port'),
+          buildDataColumn('Addresses')
+        ],
+        rows: buildDataRows(discovery),
+      ),
     );
   }
 
@@ -212,7 +215,10 @@ class DiscoveryState extends State<DiscoveryWidget> {
                 DataCell(Text(e.name ?? 'unknown')),
                 DataCell(Text(e.type ?? 'unknown')),
                 DataCell(Text(e.host ?? 'unknown')),
-                DataCell(Text(e.port != null ? '${e.port}' : 'unknown'))
+                DataCell(Text(e.port != null ? '${e.port}' : 'unknown')),
+                DataCell(Text(e.addresses != null
+                    ? renderAddresses(e.addresses)
+                    : 'unknown')),
               ],
             ))
         .toList();
@@ -265,3 +271,11 @@ Map<String, Uint8List?> createTxt() {
     'a-null': null,
   };
 }
+
+String renderAddresses(List<InternetAddress>? addresses) {
+  if (addresses == null || addresses.isEmpty) {
+    return '';
+  }
+
+  return addresses.map((a) => a.address).join('\n');
+}
diff --git a/nsd_android/android/src/main/kotlin/com/haberey/flutter/nsd_android/Serialization.kt b/nsd_android/android/src/main/kotlin/com/haberey/flutter/nsd_android/Serialization.kt
@@ -1,6 +1,9 @@
 package com.haberey.flutter.nsd_android
 
 import android.net.nsd.NsdServiceInfo
+import android.os.Build
+import java.net.Inet4Address
+import java.net.Inet6Address
 import java.net.InetAddress
 import java.nio.ByteBuffer
 import java.nio.charset.CharsetDecoder
@@ -107,16 +110,38 @@ private fun assertValidUtf8(key: String, value: ByteArray) {
 }
 
 internal fun serializeServiceInfo(nsdServiceInfo: NsdServiceInfo): Map<String, Any?> {
+    val inetAddresses = when {
+        Build.VERSION.SDK_INT >= 34 -> nsdServiceInfo.hostAddresses
+        else -> listOfNotNull(nsdServiceInfo.host)
+    }
+
+    val addressEntries = inetAddresses.mapNotNull { getAddressEntry(it) }
+
     return mapOf(
         Key.SERVICE_NAME.serializeKey to nsdServiceInfo.serviceName,
         Key.SERVICE_TYPE.serializeKey to removeLeadingAndTrailingDots(serviceType = nsdServiceInfo.serviceType),
         Key.SERVICE_HOST.serializeKey to nsdServiceInfo.host?.canonicalHostName,
-        Key.SERVICE_ADDRESSES.serializeKey to nsdServiceInfo.host?.hostAddress,
+        Key.SERVICE_ADDRESSES.serializeKey to addressEntries,
         Key.SERVICE_PORT.serializeKey to if (nsdServiceInfo.port == 0) null else nsdServiceInfo.port,
         Key.SERVICE_TXT.serializeKey to nsdServiceInfo.attributes,
     )
 }
 
+private fun getAddressEntry(addr: InetAddress): Map<String, Any?>? {
+    val addressStr = addr.hostAddress ?: return null
+
+    val typeStr = when (addr) {
+        is Inet4Address -> "ipv4"
+        is Inet6Address -> "ipv6"
+        else -> null
+    }
+
+    return mapOf(
+        "address" to addressStr,
+        "type" to typeStr,
+    )
+}
+
 // In the specification http://files.dns-sd.org/draft-cheshire-dnsext-dns-sd.txt 4.1.2 / 7.
 // it looks like leading and trailing dots do not belong to the <Service> portion but separate it
 // from the surrounding <Name> and <Domain> portions. These dots are removed here to allow
diff --git a/nsd_ios/ios/Classes/Serialization.swift b/nsd_ios/ios/Classes/Serialization.swift
@@ -31,6 +31,15 @@ func serializeService(_ netService: NetService) -> [String: Any?] {
         }
     }
 
+    if let addressDataList = netService.addresses {
+        
+        let addressEntries = addressDataList.compactMap { getAddressEntry(from: $0) }
+
+        if !addressEntries.isEmpty {
+            service["service.addresses"] = addressEntries
+        }
+    }
+
     return service
 }
 
@@ -121,3 +130,55 @@ func serializeErrorCause(_ value: ErrorCause) -> [String: Any?] {
 func serializeErrorMessage(_ value: String) -> [String: Any?] {
     ["error.message": value]
 }
+
+func getAddressEntry(from addressData: Data) -> [String: Any]? {
+    
+    // temporary access to raw bytes in data
+    addressData.withUnsafeBytes { rawBuffer in
+        
+        // rawBuffer.baseAddress can be nil if data is empty
+        guard let baseAddress = rawBuffer.baseAddress else {
+            return nil
+        }
+        
+        // get sockaddr pointer from baseAddress
+        let sockaddrPtr = baseAddress.assumingMemoryBound(to: sockaddr.self)
+
+        // prepare C-style character buffer
+        var addressData = [CChar](repeating: 0, count: Int(NI_MAXHOST))
+        
+        // length of sockaddr struct
+        let length = socklen_t(addressData.count)
+
+        // get human-readable strings from sockaddr
+        guard getnameinfo(
+            sockaddrPtr,
+            length,
+            &addressData,
+            socklen_t(addressData.count),
+            nil,
+            0,
+            NI_NUMERICHOST // request numeric address e.g. "192.168.1.10" or "fe80::1234"
+        ) == 0 else {
+            return nil
+        }
+
+        // convert C-string buffer into Swift string
+        let address = String(cString: addressData)
+
+        switch Int32(sockaddrPtr.pointee.sa_family) {
+        case AF_INET:
+            return [
+                "address": address,
+                "type": "ipv4"
+            ]
+        case AF_INET6:
+            return [
+                "address": address,
+                "type": "ipv6"
+            ]
+        default:
+            return nil
+        }
+    }
+}
diff --git a/nsd_macos/macos/Classes/Serialization.swift b/nsd_macos/macos/Classes/Serialization.swift
@@ -31,6 +31,15 @@ func serializeService(_ netService: NetService) -> [String: Any?] {
         }
     }
 
+    if let addressDataList = netService.addresses {
+        
+        let addressEntries = addressDataList.compactMap { getAddressEntry(from: $0) }
+
+        if !addressEntries.isEmpty {
+            service["service.addresses"] = addressEntries
+        }
+    }
+
     return service
 }
 
@@ -121,3 +130,55 @@ func serializeErrorCause(_ value: ErrorCause) -> [String: Any?] {
 func serializeErrorMessage(_ value: String) -> [String: Any?] {
     ["error.message": value]
 }
+
+func getAddressEntry(from addressData: Data) -> [String: Any]? {
+    
+    // temporary access to raw bytes in data
+    addressData.withUnsafeBytes { rawBuffer in
+        
+        // rawBuffer.baseAddress can be nil if data is empty
+        guard let baseAddress = rawBuffer.baseAddress else {
+            return nil
+        }
+        
+        // get sockaddr pointer from baseAddress
+        let sockaddrPtr = baseAddress.assumingMemoryBound(to: sockaddr.self)
+
+        // prepare C-style character buffer
+        var addressData = [CChar](repeating: 0, count: Int(NI_MAXHOST))
+        
+        // length of sockaddr struct
+        let length = socklen_t(addressData.count)
+
+        // get human-readable strings from sockaddr
+        guard getnameinfo(
+            sockaddrPtr,
+            length,
+            &addressData,
+            socklen_t(addressData.count),
+            nil,
+            0,
+            NI_NUMERICHOST // request numeric address e.g. "192.168.1.10" or "fe80::1234"
+        ) == 0 else {
+            return nil
+        }
+
+        // convert C-string buffer into Swift string
+        let address = String(cString: addressData)
+
+        switch Int32(sockaddrPtr.pointee.sa_family) {
+        case AF_INET:
+            return [
+                "address": address,
+                "type": "ipv4"
+            ]
+        case AF_INET6:
+            return [
+                "address": address,
+                "type": "ipv6"
+            ]
+        default:
+            return nil
+        }
+    }
+}
diff --git a/nsd_platform_interface/lib/src/method_channel_nsd_platform.dart b/nsd_platform_interface/lib/src/method_channel_nsd_platform.dart
@@ -61,9 +61,8 @@ class MethodChannelNsdPlatform extends NsdPlatformInterface {
       if (autoResolve) {
         service = await resolve(service);
 
-        if (isIpLookupEnabled(ipLookupType) && service.addresses == null) {
-          service = await performIpLookup(service, ipLookupType);
-        }
+        // TODO remove this and deprecate IpLookupType once Windows supports native addresses too
+        service = await performIpLookup(service, ipLookupType);
       }
       discovery.add(service);
     });
@@ -77,6 +76,29 @@ class MethodChannelNsdPlatform extends NsdPlatformInterface {
     }).then((value) => completer.future);
   }
 
+  Future<Service> performIpLookup(
+      Service service, IpLookupType ipLookupType) async {
+    final internetAddressType = getInternetAddressType(ipLookupType);
+    if (internetAddressType == null) {
+      return service; // lookup not enabled -> leave service as is
+    }
+
+    var addresses = service.addresses;
+    if (addresses != null && internetAddressType != InternetAddressType.any) {
+      // platform already supplied addresses -> no lookup, but respect user's choice of address type
+      addresses =
+          addresses.where((a) => a.type == internetAddressType).toList();
+    } else {
+      final host = service.host;
+      if (host == null) {
+        return service; // cannot look up addresses -> leave service as is
+      }
+      addresses = await InternetAddress.lookup(host, type: internetAddressType);
+    }
+
+    return merge(service, Service(addresses: addresses));
+  }
+
   @override
   Future<void> stopDiscovery(Discovery discovery) async {
     final completer = Completer<void>();
@@ -230,15 +252,15 @@ class MethodChannelNsdPlatform extends NsdPlatformInterface {
 }
 
 Future<Service> performIpLookup(
-    Service service, IpLookupType ipLookupType) async {
+    Service service, InternetAddressType internetAddressType) async {
   final host = service.host;
 
   if (host == null) {
     return service;
   }
 
-  final addresses = await InternetAddress.lookup(host,
-      type: getInternetAddressType(ipLookupType)!);
+  final addresses =
+      await InternetAddress.lookup(host, type: internetAddressType);
   return merge(service, Service(addresses: addresses));
 }
 
diff --git a/nsd_platform_interface/lib/src/serialization.dart b/nsd_platform_interface/lib/src/serialization.dart
