A Retrofit inspired WebSocket client for Kotlin, Java, and Android.
We are working on a new version of Scarlet that supports other persistent connection protocols: ServerSentEvent, Socket IO, STOMP, and MQTT. It can be found on the 0.2.x branch.
In this example, we read the realtime Bitcoin price from Gdax WebSocket Feed. For more information, please check out the demo app.
Declare a WebSocket client using an interface:
interface GdaxService {
@Receive
fun observeWebSocketEvent(): Flowable<WebSocket.Event>
@Send
fun sendSubscribe(subscribe: Subscribe)
@Receive
fun observeTicker(): Flowable<Ticker>
}Use Scarlet to create an implementation:
val scarletInstance = Scarlet.Builder()
.webSocketFactory(okHttpClient.newWebSocketFactory("wss://ws-feed.gdax.com"))
.addMessageAdapterFactory(MoshiMessageAdapter.Factory())
.addStreamAdapterFactory(RxJava2StreamAdapterFactory())
.build()
val gdaxService = scarletInstance.create<GdaxService>()Send a Subscribe message upon connection open and the server will start streaming tickers which contain the latest price.
val BITCOIN_TICKER_SUBSCRIBE_MESSAGE = Subscribe(
productIds = listOf("BTC-USD"),
channels = listOf("ticker")
)
gdaxService.observeWebSocketEvent()
.filter { it is WebSocket.Event.OnConnectionOpened<*> }
.subscribe({
gdaxService.sendSubscribe(BITCOIN_TICKER_SUBSCRIBE_MESSAGE)
})
gdaxService.observeTicker()
.subscribe({ ticker ->
Log.d("Bitcoin price is ${ticker.price} at ${ticker.time}")
})Scarlet is driven by a StateMachine.
TODO
Scarlet is available via Maven Central.
Snapshots of the development version are available in Sonatype's snapshots repository.
<dependency>
<groupId>com.tinder.scarlet</groupId>
<artifactId>scarlet</artifactId>
<version>0.1.12</version>
</dependency>implementation 'com.tinder.scarlet:scarlet:0.1.12'WebSocket.Factory
-
OkHttpClient -
MockHttpServer
MessageAdapter.Factory
-
moshi -
gson -
protobuf -
jackson -
simple-xml
StreamAdapter.Factory
-
RxJava2 -
RxJava1 -
Kotlin Coroutine
Lifecycle
-
AndroidLifecycle
BackoffStrategy
-
Linear -
Exponential -
ExponentialWithJitter
Copyright (c) 2018, Match Group, LLC
All rights reserved.
Redistribution and use in source and binary forms, with or without
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