e-ntfy-android/app/src/main/java/io/heckel/ntfy/msg/SubscriberConnection.kt
2021-11-27 16:18:09 -05:00

110 lines
5 KiB
Kotlin

package io.heckel.ntfy.msg
import android.util.Log
import io.heckel.ntfy.data.ConnectionState
import io.heckel.ntfy.data.Notification
import io.heckel.ntfy.data.Subscription
import io.heckel.ntfy.util.topicUrl
import kotlinx.coroutines.*
import okhttp3.Call
import java.util.concurrent.atomic.AtomicBoolean
class SubscriberConnection(
private val api: ApiService,
private val baseUrl: String,
private val sinceTime: Long,
private val subscriptions: Map<Long, Subscription>,
private val stateChangeListener: (Collection<Subscription>, ConnectionState) -> Unit,
private val notificationListener: (Subscription, Notification) -> Unit,
private val serviceActive: () -> Boolean
) {
private val topicsStr = subscriptions.values.joinToString(separator = ",") { s -> s.topic }
private val url = topicUrl(baseUrl, topicsStr)
private var since: Long = sinceTime
private lateinit var call: Call
private lateinit var job: Job
fun start(scope: CoroutineScope) {
job = scope.launch(Dispatchers.IO) {
Log.d(TAG, "[$url] Starting connection for subscriptions: $subscriptions")
// Retry-loop: if the connection fails, we retry unless the job or service is cancelled/stopped
var retryMillis = 0L
while (isActive && serviceActive()) {
Log.d(TAG, "[$url] (Re-)starting connection for subscriptions: $subscriptions")
val startTime = System.currentTimeMillis()
val notify = { topic: String, notification: Notification ->
since = notification.timestamp
val subscription = subscriptions.values.first { it.topic == topic }
val notificationWithSubscriptionId = notification.copy(subscriptionId = subscription.id)
notificationListener(subscription, notificationWithSubscriptionId)
}
val failed = AtomicBoolean(false)
val fail = { e: Exception ->
failed.set(true)
if (isActive && serviceActive()) { // Avoid UI update races if we're restarting a connection
stateChangeListener(subscriptions.values, ConnectionState.CONNECTING)
}
}
// Call /json subscribe endpoint and loop until the call fails, is canceled,
// or the job or service are cancelled/stopped
try {
call = api.subscribe(baseUrl, topicsStr, since, notify, fail)
while (!failed.get() && !call.isCanceled() && isActive && serviceActive()) {
stateChangeListener(subscriptions.values, ConnectionState.CONNECTED)
Log.d(TAG,"[$url] Connection is active (failed=$failed, callCanceled=${call.isCanceled()}, jobActive=$isActive, serviceStarted=${serviceActive()}")
delay(CONNECTION_LOOP_DELAY_MILLIS) // Resumes immediately if job is cancelled
}
} catch (e: Exception) {
Log.e(TAG, "[$url] Connection failed: ${e.message}", e)
if (isActive && serviceActive()) { // Avoid UI update races if we're restarting a connection
stateChangeListener(subscriptions.values, ConnectionState.CONNECTING)
}
}
// If we're not cancelled yet, wait little before retrying (incremental back-off)
if (isActive && serviceActive()) {
retryMillis = nextRetryMillis(retryMillis, startTime)
Log.d(TAG, "[$url] Connection failed, retrying connection in ${retryMillis / 1000}s ...")
delay(retryMillis)
}
}
Log.d(TAG, "[$url] Connection job SHUT DOWN")
// FIXME: Do NOT update state here as this can lead to races; this leaks the subscription state map
}
}
fun matches(otherSubscriptions: Map<Long, Subscription>): Boolean {
return subscriptions.keys == otherSubscriptions.keys
}
fun since(): Long {
return since
}
fun cancel() {
Log.d(TAG, "[$url] Cancelling connection")
job?.cancel()
call?.cancel()
}
private fun nextRetryMillis(retryMillis: Long, startTime: Long): Long {
val connectionDurationMillis = System.currentTimeMillis() - startTime
if (connectionDurationMillis > RETRY_RESET_AFTER_MILLIS) {
return RETRY_STEP_MILLIS
} else if (retryMillis + RETRY_STEP_MILLIS >= RETRY_MAX_MILLIS) {
return RETRY_MAX_MILLIS
}
return retryMillis + RETRY_STEP_MILLIS
}
companion object {
private const val TAG = "NtfySubscriberConn"
private const val CONNECTION_LOOP_DELAY_MILLIS = 30_000L
private const val RETRY_STEP_MILLIS = 5_000L
private const val RETRY_MAX_MILLIS = 60_000L
private const val RETRY_RESET_AFTER_MILLIS = 60_000L // Must be larger than CONNECTION_LOOP_DELAY_MILLIS
}
}