Get country change events

Country change events are events triggered whenever a subscriber changes their current country location. It will be triggered once per SIM card that changes its currently registered network's country.

The event contains both the new (current) country, and the old (previous) country, with both the ISO country code, and a readable country name.

Prerequisites

  1. An OAuth 2.0 client
  2. A client access token

Required scope

subscription.country_change:read

Code

TIP

You can test our APIs without authorization by targetting sandbox.api.wgtwo.com instead of api.wgtwo.com and removing any authorization from the request/code sample.

Download proto definitions
curl -sL 'https://github.com/working-group-two/wgtwoapis/blob/master/image.bin?raw=true' -o wgtwo.bin
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export ACCESS_TOKEN="my_client_access_token"
grpcurl -protoset wgtwo.bin \
  -H "Authorization: Bearer $ACCESS_TOKEN" \
  -d '
  {
    "stream_configuration": {
      "regular": {},
      "disable_explicit_ack": {}
    }
  }
  ' \
  api.wgtwo.com:443 \
  wgtwo.subscription.v1.SubscriptionEventService/StreamCountryChangeEvents
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About stream_configuration

For testing purposes, we include the config:

"stream_configuration": {
  "regular": {},              Reading position will not be stored in the server and load is not spread between your clients 
  "disable_explicit_ack": {}  Let events be automatically acked
}
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By default, load will automatically be spread between all connections using the same OAuth 2.0 client and you will need to reply with a ack once your service has handled the message. This is also what we would recommend for real production usage.

See configuring event streaming for details.

Example result

{
  "countryChangeEvent": {
    "previous": {
      "code": "SE",
      "name": "Sweden"
    },
    "current": {
      "code": "NO",
      "name": "Norway"
    }
  }
}
{
  "countryChangeEvent": {
    "previous": {
      "code": "NO",
      "name": "Norway"
    },
    "current": {
      "code": "SE",
      "name": "Sweden"
    }
  }
}
{
  "countryChangeEvent": {
    "previous": {
      "code": "SE",
      "name": "Sweden"
    },
    "current": {
      "code": "US",
      "name": "US"
    }
  }
}
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Install dependencies

Maven

<dependency>
  <groupId>com.wgtwo.api.v1.grpc</groupId>
  <artifactId>subscription</artifactId>
  <version>1.4.2</version>
</dependency>

search.maven.org/search?q=g:com.wgtwo.api.v1.grpcopen in new window

package com.example.countrychange

import com.google.common.util.concurrent.ThreadFactoryBuilder
import com.wgtwo.api.v1.events.EventsProto
import com.wgtwo.api.v1.events.EventsProto.AckInfo
import com.wgtwo.api.v1.subscription.SubscriptionEventServiceGrpc
import com.wgtwo.api.v1.subscription.SubscriptionEventsProto
import com.wgtwo.api.v1.subscription.SubscriptionEventsProto.AckCountryChangeEventRequest
import com.wgtwo.api.v1.subscription.SubscriptionEventsProto.AckCountryChangeEventResponse
import com.wgtwo.api.v1.subscription.SubscriptionEventsProto.StreamCountryChangeEventsResponse
import io.grpc.CallCredentials
import io.grpc.Context
import io.grpc.ManagedChannelBuilder
import io.grpc.Metadata
import io.grpc.Status
import io.grpc.StatusException
import io.grpc.StatusRuntimeException
import io.grpc.stub.StreamObserver
import java.util.concurrent.Executor
import java.util.concurrent.Executors
import java.util.concurrent.TimeUnit
import java.util.concurrent.atomic.AtomicBoolean
import java.util.function.Supplier

fun main() {
    EventHandler.start()
    Thread.sleep(60_000)
    EventHandler.close()
}

object EventHandler {
    private val isSandboxed = true // Toggle this to go live
    private val api = if (!isSandboxed) "api.wgtwo.com" else "sandbox.api.wgtwo.com"
    private val channel = ManagedChannelBuilder.forAddress(api, 443).build()
    private val subscriptionEvents = SubscriptionEventServiceGrpc.newStub(channel).apply {
        if (!isSandboxed) { // credentials are needed outside sandbox environment
            this.withCallCredentials(BearerToken { "MY_CLIENT_ACCESS_TOKEN" })
        }
    }

    private val maxInFlight: Int = EventsProto.StreamConfiguration.MAX_IN_FLIGHT_FIELD_NUMBER
    private val context = Context.current().fork().withCancellation()
    private val started = AtomicBoolean()
    private val streamExecutor = Executors.newSingleThreadScheduledExecutor()
    private val processExecutor = Executors.newFixedThreadPool(maxInFlight, thread("event-pool-%d"))

    fun start() {
        if (started.getAndSet(true)) {
            return
        }
        streamExecutor.submit(::run)
    }

    private fun run() {
        println("Starting subscription")
        val request =
            SubscriptionEventsProto.StreamCountryChangeEventsRequest.newBuilder()
                .setStreamConfiguration(
                    EventsProto.StreamConfiguration.newBuilder()
                        .setMaxInFlight(maxInFlight)
                )
                .build()
        context.run {
            subscriptionEvents.streamCountryChangeEvents(
                request,
                CountryChangeObserver
            )
        }
    }

    private fun ack(ackInfo: AckInfo) {
        val request = AckCountryChangeEventRequest.newBuilder().setAckInfo(ackInfo).build()
        subscriptionEvents.ackCountryChangeEvent(request, AckObserver)
    }

    private object CountryChangeObserver : StreamObserver<StreamCountryChangeEventsResponse> {
        override fun onNext(response: StreamCountryChangeEventsResponse) {
            processExecutor.submit {
                try {
                    println(response)
                } catch (e: Exception) {
                    println("Could not process event. e = $e")
                } finally {
                    ack(response.metadata.ackInfo)
                }
            }
        }

        override fun onError(t: Throwable) {
            val code = code(t)
            if (code == Status.Code.CANCELLED) {
                println("Cancelled - Good bye!")
                return
            }
            val delaySeconds =
                when (code) {
                    Status.Code.UNAUTHENTICATED, Status.Code.PERMISSION_DENIED -> 10L
                    else -> 1L
                }
            println("Got onError with code=${code} - restart in $delaySeconds seconds")
            streamExecutor.schedule(::run, delaySeconds, TimeUnit.SECONDS)
        }

        override fun onCompleted() = Unit

        fun code(throwable: Throwable): Status.Code =
            when (throwable) {
                is StatusRuntimeException -> throwable.status.code
                is StatusException -> throwable.status.code
                else -> Status.Code.UNKNOWN
            }
    }

    private object AckObserver : StreamObserver<AckCountryChangeEventResponse> {
        override fun onNext(value: AckCountryChangeEventResponse) =
            when (value.ackStatus.statusCode) {
                EventsProto.AckStatus.StatusCode.STATUS_CODE_SUCCESS ->
                    println("Ack success")
                else -> println("Ack failed: ${value.ackStatus}")
            }

        override fun onError(t: Throwable) = println("onError. $t")
        override fun onCompleted() = Unit
    }


    private fun thread(format: String) = ThreadFactoryBuilder().setNameFormat(format).build()

    fun close() {
        println("Starting shutdown...")
        context.cancel(null)
        streamExecutor.shutdown()
        streamExecutor.awaitTermination(10, TimeUnit.SECONDS)
        processExecutor.shutdown()
        processExecutor.awaitTermination(20, TimeUnit.SECONDS)
        channel.shutdown().awaitTermination(10, TimeUnit.SECONDS)
        println("Shutdown complete.")
    }
}

class BearerToken(private val tokenSupplier: Supplier<String>) : CallCredentials() {
    override fun applyRequestMetadata(
        requestInfo: RequestInfo, executor: Executor, metadataApplier: MetadataApplier
    ) {
        executor.execute {
            try {
                val headers = Metadata()
                val token = tokenSupplier.get()
                headers.put(AUTH_HEADER, "Bearer $token")
                metadataApplier.apply(headers)
            } catch (e: Throwable) {
                metadataApplier.fail(Status.UNAUTHENTICATED.withCause(e))
            }
        }
    }

    override fun thisUsesUnstableApi() {}

    companion object {
        private val AUTH_HEADER = Metadata.Key.of("authorization", Metadata.ASCII_STRING_MARSHALLER)
    }
}
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Example result

country_change_event {
  previous {
    code: "US"
    name: "United States"
  }
  current {
    code: "SE"
    name: "Sweden"
  }
}

# Ack success

country_change_event {
  previous {
    code: "SE"
    name: "Sweden"
  }
  current {
    code: "NO"
    name: "Norway"
  }
}

# Ack success

country_change_event {
  previous {
    code: "NO"
    name: "Norway"
  }
  current {
    code: "SE"
    name: "Sweden"
  }
}

# Ack success
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