Android NsdManager 无法发现服务
Android NsdManager not able to discover services
我 运行 遇到 Android NsdManager when following their tutorial Using Network Service Discovery 的问题。
我的网络上有几个 zeroconf/bonjour 硬件设备。从我的 mac 我可以通过以下命令从我的终端中发现所有这些
dns-sd -Z _my-mesh._tcp.
从我的 Android 应用程序的第一个 运行 我可以使用 NsdManager 完美地发现这些服务。但是,如果我重新启动应用程序并重试,则会找到 none 的服务。 onDiscoveryStarted
被成功调用,但之后没有其他任何事情。在等待期间,我可以从 mac 确认服务仍然成功。
然后我可以打开我的 Zeroconf 应用程序(在 Android 上),它会显示像我的 mac 这样的服务。当我 return 我的应用程序时,我看到它立即收到我之前预期的所有回调。所以我相信我的方法有问题,但我不确定是什么。下面是我用来发现和解析服务的代码。该视图是一个巨大的文本视图(在滚动视图中)我一直在写文本以便于调试。
import android.annotation.SuppressLint
import android.content.Context
import android.net.nsd.NsdManager
import android.net.nsd.NsdServiceInfo
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView
class MainActivity : AppCompatActivity(),
NsdManager.DiscoveryListener {
private var nsdManager: NsdManager? = null
private var text: TextView? = null
private var isResolving = false
private val services = ArrayList<ServiceWrapper>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
this.text = findViewById(R.id.text)
this.nsdManager = application.getSystemService(Context.NSD_SERVICE) as NsdManager
}
override fun onResume() {
super.onResume()
this.nsdManager?.discoverServices("_my-mesh._tcp.", NsdManager.PROTOCOL_DNS_SD, this)
write("Resume Discovering Services")
}
override fun onPause() {
super.onPause()
this.nsdManager?.stopServiceDiscovery(this)
write("Pause Discovering Services")
}
override fun onServiceFound(serviceInfo: NsdServiceInfo?) {
write("onServiceFound(serviceInfo = $serviceInfo))")
if (serviceInfo == null) {
return
}
add(serviceInfo)
}
override fun onStopDiscoveryFailed(serviceType: String?, errorCode: Int) {
write("onStopDiscoveryFailed(serviceType = $serviceType, errorCode = $errorCode)")
}
override fun onStartDiscoveryFailed(serviceType: String?, errorCode: Int) {
write("onStartDiscoveryFailed(serviceType = $serviceType, errorCode = $errorCode)")
}
override fun onDiscoveryStarted(serviceType: String?) {
write("onDiscoveryStarted(serviceType = $serviceType)")
}
override fun onDiscoveryStopped(serviceType: String?) {
write("onDiscoveryStopped(serviceType = $serviceType)")
}
override fun onServiceLost(serviceInfo: NsdServiceInfo?) {
write("onServiceLost(serviceInfo = $serviceInfo)")
}
private fun createResolveListener(): NsdManager.ResolveListener {
return object : NsdManager.ResolveListener {
override fun onResolveFailed(serviceInfo: NsdServiceInfo?, errorCode: Int) {
write("onResolveFailed(serviceInfo = $serviceInfo, errorCode = $errorCode)")
isResolving = false
resolveNext()
}
override fun onServiceResolved(serviceInfo: NsdServiceInfo?) {
write("onServiceResolved(serviceInfo = $serviceInfo)")
if (serviceInfo == null) {
return
}
for (servicewrapper in services) {
if (servicewrapper.serviceInfo.serviceName == serviceInfo.serviceName) {
servicewrapper.resolve(serviceInfo)
}
}
isResolving = false
resolveNext()
}
}
}
@SuppressLint("SetTextI18n")
private fun write(text: String?) {
this.text?.let {
it.post({
it.text = it.text.toString() + "\n" + text + "\n"
})
}
}
fun add(serviceInfo: NsdServiceInfo) {
for (servicewrapper in services) {
if (servicewrapper.serviceInfo.serviceName == serviceInfo.serviceName) {
return
}
}
services.add(ServiceWrapper(serviceInfo))
resolveNext()
}
@Synchronized
fun resolveNext() {
if (isResolving) {
return
}
isResolving = true
for (servicewrapper in services) {
if (servicewrapper.isResolved) {
continue
}
write("resolving")
this.nsdManager?.resolveService(servicewrapper.serviceInfo, createResolveListener())
return
}
isResolving = false
}
inner class ServiceWrapper(var serviceInfo: NsdServiceInfo) {
var isResolved = false
fun resolve(serviceInfo: NsdServiceInfo) {
isResolved = true
this.serviceInfo = serviceInfo
}
}
}
迟到总比不到好。直到现在才意识到其他人也有这个问题。
我们发现一些路由器正在阻止或无法正确地来回转发数据包。我们对此的解决方案是使用 wire shark 来检测其他流行的应用程序正在做什么来解决这个问题。 Android 的 NsdManager 的可定制性有限,因此需要通过 MulticastSocket 手动传输数据包。
interface NsdDiscovery {
suspend fun startDiscovery()
suspend fun stopDiscovery()
fun setListener(listener: Listener?)
fun isDiscovering(): Boolean
interface Listener {
fun onServiceFound(ip:String, local:String)
fun onServiceLost(event: ServiceEvent)
}
}
@Singleton
class ManualNsdDiscovery @Inject constructor()
: NsdDiscovery {
//region Fields
private val isDiscovering = AtomicBoolean(false)
private var socketManager: SocketManager? = null
private var listener: WeakReference<NsdDiscovery.Listener> = WeakReference<NsdDiscovery.Listener>(null)
//endregion
//region NsdDiscovery
override suspend fun startDiscovery() = withContext(Dispatchers.IO) {
if (isDiscovering()) return@withContext
this@ManualNsdDiscovery.isDiscovering.set(true)
val socketManager = SocketManager()
socketManager.start()
this@ManualNsdDiscovery.socketManager = socketManager
}
override suspend fun stopDiscovery() = withContext(Dispatchers.IO) {
if (!isDiscovering()) return@withContext
this@ManualNsdDiscovery.socketManager?.stop()
this@ManualNsdDiscovery.socketManager = null
this@ManualNsdDiscovery.isDiscovering.set(false)
}
override fun setListener(listener: NsdDiscovery.Listener?) {
this.listener = WeakReference<NsdDiscovery.Listener>(listener)
}
@Synchronized
override fun isDiscovering(): Boolean {
return this.isDiscovering.get()
}
//endregion
private inner class SocketManager {
//region Fields
private val group = InetAddress.getByName("224.0.0.251")
?: throw IllegalStateException("Can't setup group")
private val incomingNsd = IncomingNsd()
private val outgoingNsd = OutgoingNsd()
//endregion
//region Constructors
//endregion
//region Methods
suspend fun start() {
this.incomingNsd.startListening()
this.outgoingNsd.send()
}
fun stop() {
this.incomingNsd.stopListening()
}
//endregion
private inner class OutgoingNsd {
//region Fields
private val socketMutex = Mutex()
private var socket = MulticastSocket(5353)
suspend fun setUpSocket() {
this.socketMutex.withLock {
try {
this.socket = MulticastSocket(5353)
this.socket.reuseAddress = true
this.socket.joinGroup(group)
} catch (e: SocketException) {
return
}
}
}
suspend fun tearDownSocket() {
this.socketMutex.withLock {
this@OutgoingNsd.socket.close()
}
}
//ugly code but here is the packet
private val bytes = byteArrayOf(171.toByte(), 205.toByte(), 1.toByte(), 32.toByte(),
0.toByte(), 1.toByte(), 0.toByte(), 0.toByte(),
0.toByte(), 0.toByte(), 0.toByte(), 0.toByte(),
9.toByte(), 95.toByte(), 101.toByte(), 118.toByte(),
97.toByte(), 45.toByte(), 109.toByte(), 101.toByte(),
115.toByte(), 104.toByte(), 4.toByte(), 95.toByte(),
116.toByte(), 99.toByte(), 112.toByte(), 5.toByte(),
108.toByte(), 111.toByte(), 99.toByte(), 97.toByte(),
108.toByte(), 0.toByte(), 0.toByte(), 12.toByte(),
0.toByte(), 1.toByte())
private val outPacket = DatagramPacket(bytes,
bytes.size,
this@SocketManager.group,
5353)
//endregion
//region Methods
@Synchronized
suspend fun send() {
withContext(Dispatchers.Default) {
setUpSocket()
try {
this@OutgoingNsd.socket.send(this@OutgoingNsd.outPacket)
delay(1500L)
tearDownSocket()
} catch (e: Exception) {
}
}
}
//endregion
}
private inner class IncomingNsd {
//region Fields
private val isRunning = AtomicBoolean(false)
private var socket = MulticastSocket(5353)
//endregion
//region Any
fun setUpSocket() {
try {
this.socket = MulticastSocket(5353)
this.socket.reuseAddress = true
this.socket.joinGroup(group)
} catch (e: SocketException) {
} catch (e: BindException) {
}
}
fun run() {
GlobalScope.launch(Dispatchers.Default) {
setUpSocket()
try {
while (this@IncomingNsd.isRunning.get()) {
val bytes = ByteArray(4096)
val inPacket = DatagramPacket(bytes, bytes.size)
this@IncomingNsd.socket.receive(inPacket)
val incoming = DNSIncoming(inPacket)
for (answer in incoming.allAnswers) {
if (answer.key.contains("_my_mesh._tcp")) {
this@ManualNsdDiscovery.listener.get()?.onServiceFound(answer.recordSource.hostAddress, answer.name)
return@launch
}
}
}
this@IncomingNsd.socket.close()
} catch (e: Exception) {
}
}
}
//endregion
//region Methods
@Synchronized
fun startListening() {
if (this.isRunning.get()) {
return
}
this.isRunning.set(true)
run()
}
@Synchronized
fun stopListening() {
if (!this.isRunning.get()) {
return
}
this.isRunning.set(false)
}
//endregion
}
}
}
我 运行 遇到 Android NsdManager when following their tutorial Using Network Service Discovery 的问题。
我的网络上有几个 zeroconf/bonjour 硬件设备。从我的 mac 我可以通过以下命令从我的终端中发现所有这些
dns-sd -Z _my-mesh._tcp.
从我的 Android 应用程序的第一个 运行 我可以使用 NsdManager 完美地发现这些服务。但是,如果我重新启动应用程序并重试,则会找到 none 的服务。 onDiscoveryStarted
被成功调用,但之后没有其他任何事情。在等待期间,我可以从 mac 确认服务仍然成功。
然后我可以打开我的 Zeroconf 应用程序(在 Android 上),它会显示像我的 mac 这样的服务。当我 return 我的应用程序时,我看到它立即收到我之前预期的所有回调。所以我相信我的方法有问题,但我不确定是什么。下面是我用来发现和解析服务的代码。该视图是一个巨大的文本视图(在滚动视图中)我一直在写文本以便于调试。
import android.annotation.SuppressLint
import android.content.Context
import android.net.nsd.NsdManager
import android.net.nsd.NsdServiceInfo
import android.support.v7.app.AppCompatActivity
import android.os.Bundle
import android.widget.TextView
class MainActivity : AppCompatActivity(),
NsdManager.DiscoveryListener {
private var nsdManager: NsdManager? = null
private var text: TextView? = null
private var isResolving = false
private val services = ArrayList<ServiceWrapper>()
override fun onCreate(savedInstanceState: Bundle?) {
super.onCreate(savedInstanceState)
setContentView(R.layout.activity_main)
this.text = findViewById(R.id.text)
this.nsdManager = application.getSystemService(Context.NSD_SERVICE) as NsdManager
}
override fun onResume() {
super.onResume()
this.nsdManager?.discoverServices("_my-mesh._tcp.", NsdManager.PROTOCOL_DNS_SD, this)
write("Resume Discovering Services")
}
override fun onPause() {
super.onPause()
this.nsdManager?.stopServiceDiscovery(this)
write("Pause Discovering Services")
}
override fun onServiceFound(serviceInfo: NsdServiceInfo?) {
write("onServiceFound(serviceInfo = $serviceInfo))")
if (serviceInfo == null) {
return
}
add(serviceInfo)
}
override fun onStopDiscoveryFailed(serviceType: String?, errorCode: Int) {
write("onStopDiscoveryFailed(serviceType = $serviceType, errorCode = $errorCode)")
}
override fun onStartDiscoveryFailed(serviceType: String?, errorCode: Int) {
write("onStartDiscoveryFailed(serviceType = $serviceType, errorCode = $errorCode)")
}
override fun onDiscoveryStarted(serviceType: String?) {
write("onDiscoveryStarted(serviceType = $serviceType)")
}
override fun onDiscoveryStopped(serviceType: String?) {
write("onDiscoveryStopped(serviceType = $serviceType)")
}
override fun onServiceLost(serviceInfo: NsdServiceInfo?) {
write("onServiceLost(serviceInfo = $serviceInfo)")
}
private fun createResolveListener(): NsdManager.ResolveListener {
return object : NsdManager.ResolveListener {
override fun onResolveFailed(serviceInfo: NsdServiceInfo?, errorCode: Int) {
write("onResolveFailed(serviceInfo = $serviceInfo, errorCode = $errorCode)")
isResolving = false
resolveNext()
}
override fun onServiceResolved(serviceInfo: NsdServiceInfo?) {
write("onServiceResolved(serviceInfo = $serviceInfo)")
if (serviceInfo == null) {
return
}
for (servicewrapper in services) {
if (servicewrapper.serviceInfo.serviceName == serviceInfo.serviceName) {
servicewrapper.resolve(serviceInfo)
}
}
isResolving = false
resolveNext()
}
}
}
@SuppressLint("SetTextI18n")
private fun write(text: String?) {
this.text?.let {
it.post({
it.text = it.text.toString() + "\n" + text + "\n"
})
}
}
fun add(serviceInfo: NsdServiceInfo) {
for (servicewrapper in services) {
if (servicewrapper.serviceInfo.serviceName == serviceInfo.serviceName) {
return
}
}
services.add(ServiceWrapper(serviceInfo))
resolveNext()
}
@Synchronized
fun resolveNext() {
if (isResolving) {
return
}
isResolving = true
for (servicewrapper in services) {
if (servicewrapper.isResolved) {
continue
}
write("resolving")
this.nsdManager?.resolveService(servicewrapper.serviceInfo, createResolveListener())
return
}
isResolving = false
}
inner class ServiceWrapper(var serviceInfo: NsdServiceInfo) {
var isResolved = false
fun resolve(serviceInfo: NsdServiceInfo) {
isResolved = true
this.serviceInfo = serviceInfo
}
}
}
迟到总比不到好。直到现在才意识到其他人也有这个问题。
我们发现一些路由器正在阻止或无法正确地来回转发数据包。我们对此的解决方案是使用 wire shark 来检测其他流行的应用程序正在做什么来解决这个问题。 Android 的 NsdManager 的可定制性有限,因此需要通过 MulticastSocket 手动传输数据包。
interface NsdDiscovery {
suspend fun startDiscovery()
suspend fun stopDiscovery()
fun setListener(listener: Listener?)
fun isDiscovering(): Boolean
interface Listener {
fun onServiceFound(ip:String, local:String)
fun onServiceLost(event: ServiceEvent)
}
}
@Singleton
class ManualNsdDiscovery @Inject constructor()
: NsdDiscovery {
//region Fields
private val isDiscovering = AtomicBoolean(false)
private var socketManager: SocketManager? = null
private var listener: WeakReference<NsdDiscovery.Listener> = WeakReference<NsdDiscovery.Listener>(null)
//endregion
//region NsdDiscovery
override suspend fun startDiscovery() = withContext(Dispatchers.IO) {
if (isDiscovering()) return@withContext
this@ManualNsdDiscovery.isDiscovering.set(true)
val socketManager = SocketManager()
socketManager.start()
this@ManualNsdDiscovery.socketManager = socketManager
}
override suspend fun stopDiscovery() = withContext(Dispatchers.IO) {
if (!isDiscovering()) return@withContext
this@ManualNsdDiscovery.socketManager?.stop()
this@ManualNsdDiscovery.socketManager = null
this@ManualNsdDiscovery.isDiscovering.set(false)
}
override fun setListener(listener: NsdDiscovery.Listener?) {
this.listener = WeakReference<NsdDiscovery.Listener>(listener)
}
@Synchronized
override fun isDiscovering(): Boolean {
return this.isDiscovering.get()
}
//endregion
private inner class SocketManager {
//region Fields
private val group = InetAddress.getByName("224.0.0.251")
?: throw IllegalStateException("Can't setup group")
private val incomingNsd = IncomingNsd()
private val outgoingNsd = OutgoingNsd()
//endregion
//region Constructors
//endregion
//region Methods
suspend fun start() {
this.incomingNsd.startListening()
this.outgoingNsd.send()
}
fun stop() {
this.incomingNsd.stopListening()
}
//endregion
private inner class OutgoingNsd {
//region Fields
private val socketMutex = Mutex()
private var socket = MulticastSocket(5353)
suspend fun setUpSocket() {
this.socketMutex.withLock {
try {
this.socket = MulticastSocket(5353)
this.socket.reuseAddress = true
this.socket.joinGroup(group)
} catch (e: SocketException) {
return
}
}
}
suspend fun tearDownSocket() {
this.socketMutex.withLock {
this@OutgoingNsd.socket.close()
}
}
//ugly code but here is the packet
private val bytes = byteArrayOf(171.toByte(), 205.toByte(), 1.toByte(), 32.toByte(),
0.toByte(), 1.toByte(), 0.toByte(), 0.toByte(),
0.toByte(), 0.toByte(), 0.toByte(), 0.toByte(),
9.toByte(), 95.toByte(), 101.toByte(), 118.toByte(),
97.toByte(), 45.toByte(), 109.toByte(), 101.toByte(),
115.toByte(), 104.toByte(), 4.toByte(), 95.toByte(),
116.toByte(), 99.toByte(), 112.toByte(), 5.toByte(),
108.toByte(), 111.toByte(), 99.toByte(), 97.toByte(),
108.toByte(), 0.toByte(), 0.toByte(), 12.toByte(),
0.toByte(), 1.toByte())
private val outPacket = DatagramPacket(bytes,
bytes.size,
this@SocketManager.group,
5353)
//endregion
//region Methods
@Synchronized
suspend fun send() {
withContext(Dispatchers.Default) {
setUpSocket()
try {
this@OutgoingNsd.socket.send(this@OutgoingNsd.outPacket)
delay(1500L)
tearDownSocket()
} catch (e: Exception) {
}
}
}
//endregion
}
private inner class IncomingNsd {
//region Fields
private val isRunning = AtomicBoolean(false)
private var socket = MulticastSocket(5353)
//endregion
//region Any
fun setUpSocket() {
try {
this.socket = MulticastSocket(5353)
this.socket.reuseAddress = true
this.socket.joinGroup(group)
} catch (e: SocketException) {
} catch (e: BindException) {
}
}
fun run() {
GlobalScope.launch(Dispatchers.Default) {
setUpSocket()
try {
while (this@IncomingNsd.isRunning.get()) {
val bytes = ByteArray(4096)
val inPacket = DatagramPacket(bytes, bytes.size)
this@IncomingNsd.socket.receive(inPacket)
val incoming = DNSIncoming(inPacket)
for (answer in incoming.allAnswers) {
if (answer.key.contains("_my_mesh._tcp")) {
this@ManualNsdDiscovery.listener.get()?.onServiceFound(answer.recordSource.hostAddress, answer.name)
return@launch
}
}
}
this@IncomingNsd.socket.close()
} catch (e: Exception) {
}
}
}
//endregion
//region Methods
@Synchronized
fun startListening() {
if (this.isRunning.get()) {
return
}
this.isRunning.set(true)
run()
}
@Synchronized
fun stopListening() {
if (!this.isRunning.get()) {
return
}
this.isRunning.set(false)
}
//endregion
}
}
}