feat(xep): Implement inline negotiation

packages/moxxmpp/lib/src/negotiators/sasl2.dart

@@ -1,3 +1,4 @@
+import 'package:collection/collection.dart';
 import 'package:moxxmpp/src/namespaces.dart';
 import 'package:moxxmpp/src/negotiators/namespaces.dart';
 import 'package:moxxmpp/src/negotiators/negotiator.dart';
@@ -5,6 +6,18 @@ import 'package:moxxmpp/src/negotiators/sasl/negotiator.dart';
 import 'package:moxxmpp/src/stringxml.dart';
 import 'package:moxxmpp/src/types/result.dart';
 
+bool isInliningPossible(XMLNode nonza, String xmlns) {
+  assert(nonza.tag == 'authentication', 'Ensure we use the correct nonza');
+  assert(nonza.xmlns == sasl2Xmlns, 'Ensure we use the correct nonza');
+  final inline = nonza.firstTag('inline');
+  if (inline == null) {
+    return false;
+  }
+
+  return inline.children.firstWhereOrNull((child) => child.xmlns == xmlns) !=
+      null;
+}
+
 /// A special type of [XmppFeatureNegotiatorBase] that is aware of SASL2.
 abstract class Sasl2FeatureNegotiator extends XmppFeatureNegotiatorBase {
   Sasl2FeatureNegotiator(
@@ -117,6 +130,11 @@ class Sasl2Negotiator extends XmppFeatureNegotiatorBase {
   /// The SASL negotiator that will negotiate authentication.
   Sasl2AuthenticationNegotiator? _currentSaslNegotiator;
 
+  /// The SASL2 <authentication /> element we received with the stream features.
+  XMLNode? _sasl2Data;
+
+  /// Register a SASL negotiator so that we can use that SASL implementation during
+  /// SASL2.
   void registerSaslNegotiator(Sasl2AuthenticationNegotiator negotiator) {
     _featureNegotiators.add(negotiator);
     _saslNegotiators
@@ -124,21 +142,30 @@ class Sasl2Negotiator extends XmppFeatureNegotiatorBase {
       ..sort((a, b) => b.priority.compareTo(a.priority));
   }
 
+  /// Register a feature negotiator so that we can negotitate that feature inline with
+  /// the SASL authentication.
   void registerNegotiator(Sasl2FeatureNegotiator negotiator) {
     _featureNegotiators.add(negotiator);
   }
 
+  @override
+  bool matchesFeature(List<XMLNode> features) {
+    // Only do SASL2 when the socket is secure
+    return attributes.getSocket().isSecure() && super.matchesFeature(features);
+  }
+
   @override
   Future<Result<NegotiatorState, NegotiatorError>> negotiate(
     XMLNode nonza,
   ) async {
     switch (_sasl2State) {
       case Sasl2State.idle:
-        final sasl2 = nonza.firstTag('authentication', xmlns: sasl2Xmlns)!;
+        _sasl2Data = nonza.firstTag('authentication', xmlns: sasl2Xmlns);
         final mechanisms = XMLNode.xmlns(
           tag: 'mechanisms',
           xmlns: saslXmlns,
-          children: sasl2.children.where((c) => c.tag == 'mechanism').toList(),
+          children:
+              _sasl2Data!.children.where((c) => c.tag == 'mechanism').toList(),
         );
         for (final negotiator in _saslNegotiators) {
           if (negotiator.matchesFeature([mechanisms])) {
@@ -155,9 +182,11 @@ class Sasl2Negotiator extends XmppFeatureNegotiatorBase {
         // Collect additional data by interested negotiators
         final children = List<XMLNode>.empty(growable: true);
         for (final negotiator in _featureNegotiators) {
-          children.addAll(
+          if (isInliningPossible(_sasl2Data!, negotiator.negotiatingXmlns)) {
-            await negotiator.onSasl2FeaturesReceived(sasl2),
+            children.addAll(
-          );
+              await negotiator.onSasl2FeaturesReceived(_sasl2Data!),
+            );
+          }
         }
 
         // Build the authenticate nonza
@@ -183,12 +212,19 @@ class Sasl2Negotiator extends XmppFeatureNegotiatorBase {
       case Sasl2State.authenticateSent:
         if (nonza.tag == 'success') {
           // Tell the dependent negotiators about the result
+          // TODO(Unknown): This can be written in a better way
           for (final negotiator in _featureNegotiators) {
-            final result = await negotiator.onSasl2Success(nonza);
+            if (isInliningPossible(_sasl2Data!, negotiator.negotiatingXmlns)) {
-            if (!result.isType<bool>()) {
+              final result = await negotiator.onSasl2Success(nonza);
-              return Result(result.get<NegotiatorError>());
+              if (!result.isType<bool>()) {
+                return Result(result.get<NegotiatorError>());
+              }
             }
           }
+          final result = await _currentSaslNegotiator!.onSasl2Success(nonza);
+          if (!result.isType<bool>()) {
+            return Result(result.get<NegotiatorError>());
+          }
 
           // We're done
           attributes.setAuthenticated();
@@ -213,6 +249,7 @@ class Sasl2Negotiator extends XmppFeatureNegotiatorBase {
   void reset() {
     _currentSaslNegotiator = null;
     _sasl2State = Sasl2State.idle;
+    _sasl2Data = null;
 
     super.reset();
   }

packages/moxxmpp/lib/src/stringxml.dart

@@ -146,4 +146,6 @@ class XMLNode {
   String innerText() {
     return text ?? '';
   }
+
+  String? get xmlns => attributes['xmlns'] as String?;
 }

packages/moxxmpp/test/xeps/xep_0388_test.dart

@@ -3,6 +3,53 @@ import 'package:test/test.dart';
 import '../helpers/logging.dart';
 import '../helpers/xmpp.dart';
 
+class ExampleNegotiator extends Sasl2FeatureNegotiator {
+  ExampleNegotiator()
+      : super(0, false, 'invalid:example:dont:use', 'testNegotiator');
+
+  String? value;
+
+  @override
+  Future<Result<NegotiatorState, NegotiatorError>> negotiate(
+    XMLNode nonza,
+  ) async {
+    return const Result(NegotiatorState.done);
+  }
+
+  @override
+  Future<void> postRegisterCallback() async {
+    attributes
+        .getNegotiatorById<Sasl2Negotiator>(sasl2Negotiator)!
+        .registerNegotiator(this);
+  }
+
+  @override
+  Future<List<XMLNode>> onSasl2FeaturesReceived(XMLNode nonza) async {
+    if (!isInliningPossible(nonza, 'invalid:example:dont:use')) {
+      return [];
+    }
+
+    return [
+      XMLNode.xmlns(
+        tag: 'test-data-request',
+        xmlns: 'invalid:example:dont:use',
+      ),
+    ];
+  }
+
+  @override
+  Future<Result<bool, NegotiatorError>> onSasl2Success(XMLNode nonza) async {
+    final child =
+        nonza.firstTag('test-data', xmlns: 'invalid:example:dont:use');
+    if (child == null) {
+      return const Result(true);
+    }
+
+    value = child.innerText();
+    return const Result(true);
+  }
+}
+
 void main() {
   initLogger();
 
@@ -247,4 +294,175 @@ void main() {
     expect(result.isType<NegotiatorError>(), true);
     expect(result.get<NegotiatorError>() is InvalidServerSignatureError, true);
   });
+
+  test('Test simple SASL2 inlining', () async {
+    final fakeSocket = StubTCPSocket([
+      StringExpectation(
+        "<stream:stream xmlns='jabber:client' version='1.0' xmlns:stream='http://etherx.jabber.org/streams' to='test.server' xml:lang='en'>",
+        '''
+<stream:stream
+    xmlns="jabber:client"
+    version="1.0"
+    xmlns:stream="http://etherx.jabber.org/streams"
+    from="test.server"
+    xml:lang="en">
+  <stream:features xmlns="http://etherx.jabber.org/streams">
+    <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
+      <mechanism>PLAIN</mechanism>
+    </mechanisms>
+    <authentication xmlns='urn:xmpp:sasl:2'>
+      <mechanism>PLAIN</mechanism>
+      <inline>
+        <test-feature xmlns="invalid:example:dont:use" />
+      </inline>
+    </authentication>
+    <bind xmlns="urn:ietf:params:xml:ns:xmpp-bind">
+      <required/>
+    </bind>
+  </stream:features>''',
+      ),
+      StanzaExpectation(
+        "<authenticate xmlns='urn:xmpp:sasl:2' mechanism='PLAIN'><user-agent id='d4565fa7-4d72-4749-b3d3-740edbf87770'><software>moxxmpp</software><device>PapaTutuWawa's awesome device</device></user-agent><initial-response>AHBvbHlub21kaXZpc2lvbgBhYWFh</initial-response><test-data-request xmlns='invalid:example:dont:use' /></authenticate>",
+        '''
+<success xmlns='urn:xmpp:sasl:2'>
+  <authorization-identifier>polynomdivision@test.server</authorization-identifier>
+  <test-data xmlns='invalid:example:dont:use'>Hello World</test-data>
+</success>
+        ''',
+      ),
+      StanzaExpectation(
+        "<iq xmlns='jabber:client' type='set' id='aaaa'><bind xmlns='urn:ietf:params:xml:ns:xmpp-bind' /></iq>",
+        '''
+'<iq xmlns="jabber:client" type="result" id="a"><bind xmlns="urn:ietf:params:xml:ns:xmpp-bind"><jid>polynomdivision@test.server/MU29eEZn</jid></bind></iq>',
+        ''',
+        adjustId: true,
+        ignoreId: true,
+      ),
+    ]);
+    final conn = XmppConnection(
+      TestingReconnectionPolicy(),
+      AlwaysConnectedConnectivityManager(),
+      fakeSocket,
+    )..setConnectionSettings(
+        ConnectionSettings(
+          jid: JID.fromString('polynomdivision@test.server'),
+          password: 'aaaa',
+          useDirectTLS: true,
+        ),
+      );
+    await conn.registerManagers([
+      PresenceManager(),
+      RosterManager(TestingRosterStateManager('', [])),
+      DiscoManager([]),
+    ]);
+    await conn.registerFeatureNegotiators([
+      SaslPlainNegotiator(),
+      ResourceBindingNegotiator(),
+      ExampleNegotiator(),
+      Sasl2Negotiator(
+        userAgent: const UserAgent(
+          id: 'd4565fa7-4d72-4749-b3d3-740edbf87770',
+          software: 'moxxmpp',
+          device: "PapaTutuWawa's awesome device",
+        ),
+      ),
+    ]);
+
+    final result = await conn.connect(
+      waitUntilLogin: true,
+      shouldReconnect: false,
+      enableReconnectOnSuccess: false,
+    );
+    expect(result.isType<NegotiatorError>(), false);
+
+    expect(
+      conn.getNegotiatorById<ExampleNegotiator>('testNegotiator')!.value,
+      'Hello World',
+    );
+  });
+
+  test('Test simple SASL2 inlining 2', () async {
+    final fakeSocket = StubTCPSocket([
+      StringExpectation(
+        "<stream:stream xmlns='jabber:client' version='1.0' xmlns:stream='http://etherx.jabber.org/streams' to='test.server' xml:lang='en'>",
+        '''
+<stream:stream
+    xmlns="jabber:client"
+    version="1.0"
+    xmlns:stream="http://etherx.jabber.org/streams"
+    from="test.server"
+    xml:lang="en">
+  <stream:features xmlns="http://etherx.jabber.org/streams">
+    <mechanisms xmlns="urn:ietf:params:xml:ns:xmpp-sasl">
+      <mechanism>PLAIN</mechanism>
+    </mechanisms>
+    <authentication xmlns='urn:xmpp:sasl:2'>
+      <mechanism>PLAIN</mechanism>
+      <inline>
+        <resume xmlns="urn:xmpp:sm:3" />
+      </inline>
+    </authentication>
+    <bind xmlns="urn:ietf:params:xml:ns:xmpp-bind">
+      <required/>
+    </bind>
+  </stream:features>''',
+      ),
+      StanzaExpectation(
+        "<authenticate xmlns='urn:xmpp:sasl:2' mechanism='PLAIN'><user-agent id='d4565fa7-4d72-4749-b3d3-740edbf87770'><software>moxxmpp</software><device>PapaTutuWawa's awesome device</device></user-agent><initial-response>AHBvbHlub21kaXZpc2lvbgBhYWFh</initial-response></authenticate>",
+        '''
+<success xmlns='urn:xmpp:sasl:2'>
+  <authorization-identifier>polynomdivision@test.server</authorization-identifier>
+</success>
+        ''',
+      ),
+      StanzaExpectation(
+        "<iq xmlns='jabber:client' type='set' id='aaaa'><bind xmlns='urn:ietf:params:xml:ns:xmpp-bind' /></iq>",
+        '''
+'<iq xmlns="jabber:client" type="result" id="a"><bind xmlns="urn:ietf:params:xml:ns:xmpp-bind"><jid>polynomdivision@test.server/MU29eEZn</jid></bind></iq>',
+        ''',
+        adjustId: true,
+        ignoreId: true,
+      ),
+    ]);
+    final conn = XmppConnection(
+      TestingReconnectionPolicy(),
+      AlwaysConnectedConnectivityManager(),
+      fakeSocket,
+    )..setConnectionSettings(
+        ConnectionSettings(
+          jid: JID.fromString('polynomdivision@test.server'),
+          password: 'aaaa',
+          useDirectTLS: true,
+        ),
+      );
+    await conn.registerManagers([
+      PresenceManager(),
+      RosterManager(TestingRosterStateManager('', [])),
+      DiscoManager([]),
+    ]);
+    await conn.registerFeatureNegotiators([
+      SaslPlainNegotiator(),
+      ResourceBindingNegotiator(),
+      ExampleNegotiator(),
+      Sasl2Negotiator(
+        userAgent: const UserAgent(
+          id: 'd4565fa7-4d72-4749-b3d3-740edbf87770',
+          software: 'moxxmpp',
+          device: "PapaTutuWawa's awesome device",
+        ),
+      ),
+    ]);
+
+    final result = await conn.connect(
+      waitUntilLogin: true,
+      shouldReconnect: false,
+      enableReconnectOnSuccess: false,
+    );
+    expect(result.isType<NegotiatorError>(), false);
+
+    expect(
+      conn.getNegotiatorById<ExampleNegotiator>('testNegotiator')!.value,
+      null,
+    );
+  });
 }