This library has been built in order to provide a Reactive wrapper around the Android Network Service Discovery API and the JmDNS implementation for older devices.
From Wikipedia:
Zero-configuration networking (zeroconf) is a set of technologies that automatically creates a usable computer network based on the Internet Protocol Suite (TCP/IP) when computers or network peripherals are interconnected. It does not require manual operator intervention or special configuration servers.
Zeroconf is built on three core technologies: assignment of numeric network addresses for networked devices, automatic distribution and resolution of computer hostnames, and automatic location of network services, such as printing devices. Without zeroconf, a network administrator must set up services, such as Dynamic Host Configuration Protocol (DHCP) and Domain Name System (DNS), or configure each computer's network settings manually.
You might have heard more about the Bonjour Service from Apple, that is the custom implementation of Zeroconf protocol.
As an example, you can see Zeroconf working in the Chromecast environment, where you don't specify the address of the device, but it gets found easily by the apps. Zeroconf is how it happens.
Add the JitPack repository to the root build.gradle file of your project
allprojects {
repositories {
...
maven { url "https://jitpack.io" }
}
}Import the library in your app's module build.gradle
dependencies {
...
implementation 'com.github.xiaogegexiao:rxbonjour:1.0.8'
}Add the JitPack repository to your build file
<repositories>
<repository>
<id>jitpack.io</id>
<url>https://jitpack.io</url>
</repository>
</repositories>Add the dependency
<dependency>
<groupId>com.github.xiaogegexiao</groupId>
<artifactId>rxbonjour</artifactId>
<version>1.0.8</version>
</dependency>All the calls made by this library are written so that the chain is executed on a separate thread and the result of the computation is returned back on the main thread
Note: the calls to the methods included in the RxBonjour class return a Disposable that awaits for the dispose in order to kill the advertising or the discovery service. As a surplus, we wired in the logic needed to be compatible to the RxLifecycle library so that, if you compose the Observable with the Activity or Fragment events, it will tear down the service correctly as well.
All the methods of this library will emit object of the NetworkServiceDiscoveryInfo class, that is a wrapper for both the NsdServiceInfo provided by the Android API and the ServiceInfo that comes with the JmDNS library.
When you need to start advertising your service, you need to provide the factory method with a few parameters, so that the API can build up the request.
Since the Android implementation can be used only from Android 4.1, for previous versions of the system it will be automatically used the JmDNS implementation. Unfortunately, if you need to pass custom attributes to the service, Android supports it only from version 5.1 (API 21) so, in that case, the library will revert to the JmDNS implementation in order to give the desired behaviour.
But due to the existing NsdManager issue in Android SDK, with using Android NsdManager, it will not be able to get extra attributes(txt record) before Nougat. I made the change to use JmDNS before Anrdoid Nougat
Declaration:
public static Observable<NetworkServiceDiscoveryInfo> advertise(@NonNull Context context,
@NonNull String serviceName,
@NonNull String serviceLayer,
int servicePort,
@Nullable Map<String, String> attributes)Usage:
Disposable s = RxBonjour.advertise(context, "RxBonjour", "_http._tcp.", 8888, getAttributes())
.subscribe(onNext, onError, onComplete);As per API limitation, listing all the services available in the current network will not allow the components to resolve them. That means that you will have to call the
startDiscovery(Context, String)on the specific protocol for having the data resolved correctly. If, when doing so you receive an exception from theDiscoveryListener, make sure you closed the previousSubscriptionbefore starting a new one.
Declaration:
public static Observable<NetworkServiceDiscoveryInfo> startDiscovery(@NonNull Context context)Usage:
Disposable s = RxBonjour.startDiscovery(context).subscribe(onNext, onError, onComplete);If you need to discover all the devices advertising a specific protocol, you shall use the startDiscovery(Context, String) factory method as this one will allow the resolution of the services and the item received will be ready to be consumed by your logic.
As per design choice, this factory method will throw a
NsdExceptionif protocol equals either the"_services._dns-sd._udp"value or theALL_AVAILABLE_SERVICES. This a wanted behaviour that can alert you before you ship the product with an unwanted behaviour in it.
This method will not throw any other type of exception but it will notifiy you of errors while discovering the services with the usualonErrorcallback
Declaration:
public static Observable<NetworkServiceDiscoveryInfo> startDiscovery(
@NonNull Context context, @NonNull String protocol) throws NsdExceptionUsage:
Disposable s = RxBonjour.startDiscovery(context, "_http._tcp.").subscribe(onNext, onError, onComplete);Copyright (c) 2018 Xiao Mei.
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