Gists for https://medium.com/@josiassena/graphql-websocket-subscriptions-on-android-using-apollo-7e7311afdfca

ApolloSubscriptionClientFactory.kt

class ApolloSubscriptionClientFactory {
    
  fun createSubscriptionApolloClient(sharedOkHttpClientBuilder: OkHttpClient.Builder): ApolloClient {
      val okHttpClient = sharedOkHttpClientBuilder
            .pingInterval(KEEP_ALIVE_INTERVAL, TimeUnit.SECONDS)
            .build()
    
      val subscriptionTransportFactory = WebSocketSubscriptionTransport.Factory("wss://your_subscription_host/graphql", okHttpClient)
    
      return ApolloClient.builder()
          .serverUrl("https://your_host_url/graphql")
          .okHttpClient(okHttpClient)
          .subscriptionConnectionParams(HeadersProvider.HEADERS)
          .subscriptionTransportFactory(subscriptionTransportFactory)
          .build()
    }

    // ...
}

GraphQLApi.kt

class GraphQLApi(private val sharedOkHttpClientBuilder: OkHttpClient.Builder) {

    // ...

    fun <D : Operation.Data, V : Operation.Variables> subscribe(subscription: Subscription<D, D, V>): Flowable<Response<D>> {

        // Create our dedicated apollo client
        val apolloClient = ApolloSubscriptionClientFactory(sharedOkHttpClientBuilder)
            .createSubscriptionApolloClient()

        // Perform the actual subscription
        val call = apolloClient.subscribe(subscription)

        // Subscribe using Rx2Apollo
        return Rx2Apollo.from<D>(call)
    }

    // ...
}

HeadersProvider.kt

object HeadersProvider {
    val HEADERS = mapOf(
        "Authorization" to "Bearer XYZ",
        "other_shared_headers" to "etc.."
    )
}

SomePresenterOrViewModelEtc.kt

class SomePresenterOrViewModelEtc(private val api: GraphQLApi) {

    // ...

    fun sunscribeToMessages() {
        val messagesSubscription = OnNewMessagesReceivedSubscription.builder()
            .groupUUID("uuid")
            .build()

        api.subscribe(messagesSubscription)
            .subscribeOn(Schedulers.io())
            .observeOn(AndroidSchedulers.mainThread())
            .subscribe({
                // handle results, like adding the result into a list
            }, {
                // handle errors
            }).addTo(compositeDisposable)
    }

    // ...
}

subscription.graphql

subscription onNewMessagesReceived($groupUUID: String!) {
    groupChatSubscription(group: $groupUUID) {
        ... on Message {
                uuid
        }
    }
}