packages/flutter_tools/lib/src/mdns_discovery.dart - mirrors/flutter - Git at Google

 // Copyright 2014 The Flutter Authors. All rights reserved.
 // Use of this source code is governed by a BSD-style license that can be
 // found in the LICENSE file.

 import 'package:meta/meta.dart';
 import 'package:multicast_dns/multicast_dns.dart';

 import 'base/common.dart';
 import 'base/context.dart';
 import 'base/io.dart';
 import 'base/logger.dart';
 import 'build_info.dart';
 import 'device.dart';
 import 'reporting/reporting.dart';

 /// A wrapper around [MDnsClient] to find a Dart observatory instance.
 class MDnsObservatoryDiscovery {
   /// Creates a new [MDnsObservatoryDiscovery] object.
   ///
   /// The [_client] parameter will be defaulted to a new [MDnsClient] if null.
   /// The [applicationId] parameter may be null, and can be used to
   /// automatically select which application to use if multiple are advertising
   /// Dart observatory ports.
   MDnsObservatoryDiscovery({
     MDnsClient? mdnsClient,
     required Logger logger,
     required Usage flutterUsage,
   }): _client = mdnsClient ?? MDnsClient(),
       _logger = logger,
       _flutterUsage = flutterUsage;

   final MDnsClient _client;
   final Logger _logger;
   final Usage _flutterUsage;

   @visibleForTesting
   static const String dartObservatoryName = '_dartobservatory._tcp.local';

   static MDnsObservatoryDiscovery? get instance => context.get<MDnsObservatoryDiscovery>();

   /// Executes an mDNS query for a Dart Observatory.
   ///
   /// The [applicationId] parameter may be used to specify which application
   /// to find. For Android, it refers to the package name; on iOS, it refers to
   /// the bundle ID.
   ///
   /// If it is not null, this method will find the port and authentication code
   /// of the Dart Observatory for that application. If it cannot find a Dart
   /// Observatory matching that application identifier, it will call
   /// [throwToolExit].
   ///
   /// If it is null and there are multiple ports available, the user will be
   /// prompted with a list of available observatory ports and asked to select
   /// one.
   ///
   /// If it is null and there is only one available instance of Observatory,
   /// it will return that instance's information regardless of what application
   /// the Observatory instance is for.
   @visibleForTesting
   Future<MDnsObservatoryDiscoveryResult?> query({String? applicationId, int? deviceVmservicePort}) async {
     _logger.printTrace('Checking for advertised Dart observatories...');
     try {
       await _client.start();
       final List<PtrResourceRecord> pointerRecords = await _client
         .lookup<PtrResourceRecord>(
           ResourceRecordQuery.serverPointer(dartObservatoryName),
         )
         .toList();
       if (pointerRecords.isEmpty) {
         _logger.printTrace('No pointer records found.');
         return null;
       }
       // We have no guarantee that we won't get multiple hits from the same
       // service on this.
       final Set<String> uniqueDomainNames = pointerRecords
         .map<String>((PtrResourceRecord record) => record.domainName)
         .toSet();

       String? domainName;
       if (applicationId != null) {
         for (final String name in uniqueDomainNames) {
           if (name.toLowerCase().startsWith(applicationId.toLowerCase())) {
             domainName = name;
             break;
           }
         }
         if (domainName == null) {
           throwToolExit('Did not find a observatory port advertised for $applicationId.');
         }
       } else if (uniqueDomainNames.length > 1) {
         final StringBuffer buffer = StringBuffer();
         buffer.writeln('There are multiple observatory ports available.');
         buffer.writeln('Rerun this command with one of the following passed in as the appId:');
         buffer.writeln();
         for (final String uniqueDomainName in uniqueDomainNames) {
           buffer.writeln('  flutter attach --app-id ${uniqueDomainName.replaceAll('.$dartObservatoryName', '')}');
         }
         throwToolExit(buffer.toString());
       } else {
         domainName = pointerRecords[0].domainName;
       }
       _logger.printTrace('Checking for available port on $domainName');
       // Here, if we get more than one, it should just be a duplicate.
       final List<SrvResourceRecord> srv = await _client
         .lookup<SrvResourceRecord>(
           ResourceRecordQuery.service(domainName),
         )
         .toList();
       if (srv.isEmpty) {
         return null;
       }
       if (srv.length > 1) {
         _logger.printWarning('Unexpectedly found more than one observatory report for $domainName '
                    '- using first one (${srv.first.port}).');
       }
       _logger.printTrace('Checking for authentication code for $domainName');
       final List<TxtResourceRecord> txt = await _client
         .lookup<TxtResourceRecord>(
             ResourceRecordQuery.text(domainName),
         )
         .toList();
       if (txt == null || txt.isEmpty) {
         return MDnsObservatoryDiscoveryResult(srv.first.port, '');
       }
       const String authCodePrefix = 'authCode=';
       String? raw;
       for (final String record in txt.first.text.split('\n')) {
         if (record.startsWith(authCodePrefix)) {
           raw = record;
           break;
         }
       }
       if (raw == null) {
         return MDnsObservatoryDiscoveryResult(srv.first.port, '');
       }
       String authCode = raw.substring(authCodePrefix.length);
       // The Observatory currently expects a trailing '/' as part of the
       // URI, otherwise an invalid authentication code response is given.
       if (!authCode.endsWith('/')) {
         authCode += '/';
       }
       return MDnsObservatoryDiscoveryResult(srv.first.port, authCode);
     } finally {
       _client.stop();
     }
   }

   Future<Uri?> getObservatoryUri(String? applicationId, Device device, {
     bool usesIpv6 = false,
     int? hostVmservicePort,
     int? deviceVmservicePort,
   }) async {
     final MDnsObservatoryDiscoveryResult? result = await query(
       applicationId: applicationId,
       deviceVmservicePort: deviceVmservicePort,
     );
     if (result == null) {
       await _checkForIPv4LinkLocal(device);
       return null;
     }

     final String host = usesIpv6
       ? InternetAddress.loopbackIPv6.address
       : InternetAddress.loopbackIPv4.address;
     return buildObservatoryUri(
       device,
       host,
       result.port,
       hostVmservicePort,
       result.authCode,
     );
   }

   // If there's not an ipv4 link local address in `NetworkInterfaces.list`,
   // then request user interventions with a `printError()` if possible.
   Future<void> _checkForIPv4LinkLocal(Device device) async {
     _logger.printTrace(
       'mDNS query failed. Checking for an interface with a ipv4 link local address.'
     );
     final List<NetworkInterface> interfaces = await listNetworkInterfaces(
       includeLinkLocal: true,
       type: InternetAddressType.IPv4,
     );
     if (_logger.isVerbose) {
       _logInterfaces(interfaces);
     }
     final bool hasIPv4LinkLocal = interfaces.any(
       (NetworkInterface interface) => interface.addresses.any(
         (InternetAddress address) => address.isLinkLocal,
       ),
     );
     if (hasIPv4LinkLocal) {
       _logger.printTrace('An interface with an ipv4 link local address was found.');
       return;
     }
     final TargetPlatform targetPlatform = await device.targetPlatform;
     switch (targetPlatform) {
       case TargetPlatform.ios:
         UsageEvent('ios-mdns', 'no-ipv4-link-local', flutterUsage: _flutterUsage).send();
         _logger.printError(
           'The mDNS query for an attached iOS device failed. It may '
           'be necessary to disable the "Personal Hotspot" on the device, and '
           'to ensure that the "Disable unless needed" setting is unchecked '
           'under System Preferences > Network > iPhone USB. '
           'See https://github.com/flutter/flutter/issues/46698 for details.'
         );
         break;
       case TargetPlatform.android:
       case TargetPlatform.android_arm:
       case TargetPlatform.android_arm64:
       case TargetPlatform.android_x64:
       case TargetPlatform.android_x86:
       case TargetPlatform.darwin:
       case TargetPlatform.fuchsia_arm64:
       case TargetPlatform.fuchsia_x64:
       case TargetPlatform.linux_arm64:
       case TargetPlatform.linux_x64:
       case TargetPlatform.tester:
       case TargetPlatform.web_javascript:
       case TargetPlatform.windows_x64:
         _logger.printTrace('No interface with an ipv4 link local address was found.');
         break;
     }
   }

   void _logInterfaces(List<NetworkInterface> interfaces) {
     for (final NetworkInterface interface in interfaces) {
       if (_logger.isVerbose) {
         _logger.printTrace('Found interface "${interface.name}":');
         for (final InternetAddress address in interface.addresses) {
           final String linkLocal = address.isLinkLocal ? 'link local' : '';
           _logger.printTrace('\tBound address: "${address.address}" $linkLocal');
         }
       }
     }
   }
 }

 class MDnsObservatoryDiscoveryResult {
   MDnsObservatoryDiscoveryResult(this.port, this.authCode);
   final int port;
   final String authCode;
 }

 Future<Uri> buildObservatoryUri(
   Device device,
   String host,
   int devicePort, [
   int? hostVmservicePort,
   String? authCode,
 ]) async {
   String path = '/';
   if (authCode != null) {
     path = authCode;
   }
   // Not having a trailing slash can cause problems in some situations.
   // Ensure that there's one present.
   if (!path.endsWith('/')) {
     path += '/';
   }
   hostVmservicePort ??= 0;
   final int? actualHostPort = hostVmservicePort == 0 ?
     await device.portForwarder?.forward(devicePort) :
     hostVmservicePort;
   return Uri(scheme: 'http', host: host, port: actualHostPort, path: path);
 }
	// Copyright 2014 The Flutter Authors. All rights reserved.
	// Use of this source code is governed by a BSD-style license that can be
	// found in the LICENSE file.

	import 'package:meta/meta.dart';
	import 'package:multicast_dns/multicast_dns.dart';

	import 'base/common.dart';
	import 'base/context.dart';
	import 'base/io.dart';
	import 'base/logger.dart';
	import 'build_info.dart';
	import 'device.dart';
	import 'reporting/reporting.dart';

	/// A wrapper around [MDnsClient] to find a Dart observatory instance.
	class MDnsObservatoryDiscovery {
	/// Creates a new [MDnsObservatoryDiscovery] object.
	///
	/// The [_client] parameter will be defaulted to a new [MDnsClient] if null.
	/// The [applicationId] parameter may be null, and can be used to
	/// automatically select which application to use if multiple are advertising
	/// Dart observatory ports.
	MDnsObservatoryDiscovery({
	MDnsClient? mdnsClient,
	required Logger logger,
	required Usage flutterUsage,
	}): _client = mdnsClient ?? MDnsClient(),
	_logger = logger,
	_flutterUsage = flutterUsage;

	final MDnsClient _client;
	final Logger _logger;
	final Usage _flutterUsage;

	@visibleForTesting
	static const String dartObservatoryName = '_dartobservatory._tcp.local';

	static MDnsObservatoryDiscovery? get instance => context.get<MDnsObservatoryDiscovery>();

	/// Executes an mDNS query for a Dart Observatory.
	///
	/// The [applicationId] parameter may be used to specify which application
	/// to find. For Android, it refers to the package name; on iOS, it refers to
	/// the bundle ID.
	///
	/// If it is not null, this method will find the port and authentication code
	/// of the Dart Observatory for that application. If it cannot find a Dart
	/// Observatory matching that application identifier, it will call
	/// [throwToolExit].
	///
	/// If it is null and there are multiple ports available, the user will be
	/// prompted with a list of available observatory ports and asked to select
	/// one.
	///
	/// If it is null and there is only one available instance of Observatory,
	/// it will return that instance's information regardless of what application
	/// the Observatory instance is for.
	@visibleForTesting
	Future<MDnsObservatoryDiscoveryResult?> query({String? applicationId, int? deviceVmservicePort}) async {
	_logger.printTrace('Checking for advertised Dart observatories...');
	try {
	await _client.start();
	final List<PtrResourceRecord> pointerRecords = await _client
	.lookup<PtrResourceRecord>(
	ResourceRecordQuery.serverPointer(dartObservatoryName),
	)
	.toList();
	if (pointerRecords.isEmpty) {
	_logger.printTrace('No pointer records found.');
	return null;
	}
	// We have no guarantee that we won't get multiple hits from the same
	// service on this.
	final Set<String> uniqueDomainNames = pointerRecords
	.map<String>((PtrResourceRecord record) => record.domainName)
	.toSet();

	String? domainName;
	if (applicationId != null) {
	for (final String name in uniqueDomainNames) {
	if (name.toLowerCase().startsWith(applicationId.toLowerCase())) {
	domainName = name;
	break;
	}
	}
	if (domainName == null) {
	throwToolExit('Did not find a observatory port advertised for $applicationId.');
	}
	} else if (uniqueDomainNames.length > 1) {
	final StringBuffer buffer = StringBuffer();
	buffer.writeln('There are multiple observatory ports available.');
	buffer.writeln('Rerun this command with one of the following passed in as the appId:');
	buffer.writeln();
	for (final String uniqueDomainName in uniqueDomainNames) {
	buffer.writeln(' flutter attach --app-id ${uniqueDomainName.replaceAll('.$dartObservatoryName', '')}');
	}
	throwToolExit(buffer.toString());
	} else {
	domainName = pointerRecords[0].domainName;
	}
	_logger.printTrace('Checking for available port on $domainName');
	// Here, if we get more than one, it should just be a duplicate.
	final List<SrvResourceRecord> srv = await _client
	.lookup<SrvResourceRecord>(
	ResourceRecordQuery.service(domainName),
	)
	.toList();
	if (srv.isEmpty) {
	return null;
	}
	if (srv.length > 1) {
	_logger.printWarning('Unexpectedly found more than one observatory report for $domainName '
	'- using first one (${srv.first.port}).');
	}
	_logger.printTrace('Checking for authentication code for $domainName');
	final List<TxtResourceRecord> txt = await _client
	.lookup<TxtResourceRecord>(
	ResourceRecordQuery.text(domainName),
	)
	.toList();
	if (txt == null \|\| txt.isEmpty) {
	return MDnsObservatoryDiscoveryResult(srv.first.port, '');
	}
	const String authCodePrefix = 'authCode=';
	String? raw;
	for (final String record in txt.first.text.split('\n')) {
	if (record.startsWith(authCodePrefix)) {
	raw = record;
	break;
	}
	}
	if (raw == null) {
	return MDnsObservatoryDiscoveryResult(srv.first.port, '');
	}
	String authCode = raw.substring(authCodePrefix.length);
	// The Observatory currently expects a trailing '/' as part of the
	// URI, otherwise an invalid authentication code response is given.
	if (!authCode.endsWith('/')) {
	authCode += '/';
	}
	return MDnsObservatoryDiscoveryResult(srv.first.port, authCode);
	} finally {
	_client.stop();
	}
	}

	Future<Uri?> getObservatoryUri(String? applicationId, Device device, {
	bool usesIpv6 = false,
	int? hostVmservicePort,
	int? deviceVmservicePort,
	}) async {
	final MDnsObservatoryDiscoveryResult? result = await query(
	applicationId: applicationId,
	deviceVmservicePort: deviceVmservicePort,
	);
	if (result == null) {
	await _checkForIPv4LinkLocal(device);
	return null;
	}

	final String host = usesIpv6
	? InternetAddress.loopbackIPv6.address
	: InternetAddress.loopbackIPv4.address;
	return buildObservatoryUri(
	device,
	host,
	result.port,
	hostVmservicePort,
	result.authCode,
	);
	}

	// If there's not an ipv4 link local address in `NetworkInterfaces.list`,
	// then request user interventions with a `printError()` if possible.
	Future<void> _checkForIPv4LinkLocal(Device device) async {
	_logger.printTrace(
	'mDNS query failed. Checking for an interface with a ipv4 link local address.'
	);
	final List<NetworkInterface> interfaces = await listNetworkInterfaces(
	includeLinkLocal: true,
	type: InternetAddressType.IPv4,
	);
	if (_logger.isVerbose) {
	_logInterfaces(interfaces);
	}
	final bool hasIPv4LinkLocal = interfaces.any(
	(NetworkInterface interface) => interface.addresses.any(
	(InternetAddress address) => address.isLinkLocal,
	),
	);
	if (hasIPv4LinkLocal) {
	_logger.printTrace('An interface with an ipv4 link local address was found.');
	return;
	}
	final TargetPlatform targetPlatform = await device.targetPlatform;
	switch (targetPlatform) {
	case TargetPlatform.ios:
	UsageEvent('ios-mdns', 'no-ipv4-link-local', flutterUsage: _flutterUsage).send();
	_logger.printError(
	'The mDNS query for an attached iOS device failed. It may '
	'be necessary to disable the "Personal Hotspot" on the device, and '
	'to ensure that the "Disable unless needed" setting is unchecked '
	'under System Preferences > Network > iPhone USB. '
	'See https://github.com/flutter/flutter/issues/46698 for details.'
	);
	break;
	case TargetPlatform.android:
	case TargetPlatform.android_arm:
	case TargetPlatform.android_arm64:
	case TargetPlatform.android_x64:
	case TargetPlatform.android_x86:
	case TargetPlatform.darwin:
	case TargetPlatform.fuchsia_arm64:
	case TargetPlatform.fuchsia_x64:
	case TargetPlatform.linux_arm64:
	case TargetPlatform.linux_x64:
	case TargetPlatform.tester:
	case TargetPlatform.web_javascript:
	case TargetPlatform.windows_x64:
	_logger.printTrace('No interface with an ipv4 link local address was found.');
	break;
	}
	}

	void _logInterfaces(List<NetworkInterface> interfaces) {
	for (final NetworkInterface interface in interfaces) {
	if (_logger.isVerbose) {
	_logger.printTrace('Found interface "${interface.name}":');
	for (final InternetAddress address in interface.addresses) {
	final String linkLocal = address.isLinkLocal ? 'link local' : '';
	_logger.printTrace('\tBound address: "${address.address}" $linkLocal');
	}
	}
	}
	}
	}

	class MDnsObservatoryDiscoveryResult {
	MDnsObservatoryDiscoveryResult(this.port, this.authCode);
	final int port;
	final String authCode;
	}

	Future<Uri> buildObservatoryUri(
	Device device,
	String host,
	int devicePort, [
	int? hostVmservicePort,
	String? authCode,
	]) async {
	String path = '/';
	if (authCode != null) {
	path = authCode;
	}
	// Not having a trailing slash can cause problems in some situations.
	// Ensure that there's one present.
	if (!path.endsWith('/')) {
	path += '/';
	}
	hostVmservicePort ??= 0;
	final int? actualHostPort = hostVmservicePort == 0 ?
	await device.portForwarder?.forward(devicePort) :
	hostVmservicePort;
	return Uri(scheme: 'http', host: host, port: actualHostPort, path: path);
	}