negotiate method
- XMLNode nonza
override
Called with the currently received nonza nonza
when the negotiator is active.
If the negotiator is just elected to be the next one, then nonza
is equal to
the <stream:features /> nonza.
Returns the next state of the negotiator. If done or retryLater is selected, then negotiator won't be called again. If retryLater is returned, then the negotiator must switch some internal state to prevent getting matched immediately again. If ready is returned, then the negotiator indicates that it is not done with negotiation.
Implementation
@override
Future<Result<NegotiatorState, NegotiatorError>> negotiate(
XMLNode nonza,
) async {
switch (_sasl2State) {
case Sasl2State.idle:
_sasl2Data = nonza.firstTag('authentication', xmlns: sasl2Xmlns);
final mechanisms = XMLNode.xmlns(
tag: 'mechanisms',
xmlns: saslXmlns,
children:
_sasl2Data!.children.where((c) => c.tag == 'mechanism').toList(),
);
for (final negotiator in _saslNegotiators) {
if (negotiator.matchesFeature([mechanisms])) {
_currentSaslNegotiator = negotiator;
_currentSaslNegotiator!.pickForSasl2();
break;
}
}
// We must have a SASL negotiator by now
if (_currentSaslNegotiator == null) {
return Result(NoSASLMechanismSelectedError());
}
// Collect additional data by interested negotiators
final inline = _sasl2Data!.firstTag('inline');
final children = List<XMLNode>.empty(growable: true);
if (inline != null && inline.children.isNotEmpty) {
for (final negotiator in _featureNegotiators) {
if (negotiator.canInlineFeature(inline.children)) {
_activeSasl2Negotiators.add(negotiator.id);
children.addAll(
await negotiator.onSasl2FeaturesReceived(_sasl2Data!),
);
}
}
}
// Build the authenticate nonza
final authenticate = XMLNode.xmlns(
tag: 'authenticate',
xmlns: sasl2Xmlns,
attributes: {
'mechanism': _currentSaslNegotiator!.mechanismName,
},
children: [
XMLNode(
tag: 'initial-response',
text: await _currentSaslNegotiator!.getRawStep(''),
),
if (userAgent != null) userAgent!.toXml(),
...children,
],
);
_sasl2State = Sasl2State.authenticateSent;
attributes.sendNonza(authenticate);
return const Result(NegotiatorState.ready);
case Sasl2State.authenticateSent:
if (nonza.tag == 'success') {
// Tell the dependent negotiators about the result
final negotiators = _featureNegotiators
.where(
(negotiator) => _activeSasl2Negotiators.contains(negotiator.id),
)
.toList()
..add(_currentSaslNegotiator!);
for (final negotiator in negotiators) {
final result = await negotiator.onSasl2Success(nonza);
if (!result.isType<bool>()) {
return Result(result.get<NegotiatorError>());
}
}
// We're done
attributes.setAuthenticated();
attributes.removeNegotiatingFeature(saslXmlns);
// Check if we also received a resource with the SASL2 success
final jid = JID.fromString(
nonza.firstTag('authorization-identifier')!.innerText(),
);
if (!jid.isBare()) {
attributes.setResource(jid.resource);
}
return const Result(NegotiatorState.done);
} else if (nonza.tag == 'challenge') {
// We still have to negotiate
final challenge = nonza.innerText();
final response = XMLNode.xmlns(
tag: 'response',
xmlns: sasl2Xmlns,
text: await _currentSaslNegotiator!.getRawStep(challenge),
);
attributes.sendNonza(response);
} else if (nonza.tag == 'failure') {
final negotiators = _featureNegotiators
.where(
(negotiator) => _activeSasl2Negotiators.contains(negotiator.id),
)
.toList()
..add(_currentSaslNegotiator!);
for (final negotiator in negotiators) {
await negotiator.onSasl2Failure(nonza);
}
// Check if we should retry and, if we should, reset the current
// negotiator, this negotiator, and retry.
if (_currentSaslNegotiator!.shouldRetrySasl()) {
_currentSaslNegotiator!.reset();
reset();
return const Result(
NegotiatorState.retryLater,
);
}
return Result(
SaslError.fromFailure(nonza),
);
}
}
return const Result(NegotiatorState.ready);
}