Instant delivery

README.md

@@ -1,9 +1,6 @@
 # ntfy Android App
-This is the Android app for [ntfy](https://github.com/binwiederhier/ntfy) ([ntfy.sh](https://ntfy.sh)).
-
-## Current limitations
-* The app on the Play store only works with ntfy.sh, not with other hosts, due to the fact that background services in 
-  Android are pretty much impossible to implement.
+This is the Android app for [ntfy](https://github.com/binwiederhier/ntfy) ([ntfy.sh](https://ntfy.sh)). It is available 
+in the [Play Store](https://play.google.com/store/apps/details?id=io.heckel.ntfy).
 
 ## License
 Made with ❤️ by [Philipp C. Heckel](https://heckel.io), distributed under the [Apache License 2.0](LICENSE).
@@ -14,5 +11,4 @@ Thank you to these fantastic resources:
 * [Android Room with a View](https://github.com/googlecodelabs/android-room-with-a-view/tree/kotlin) (Apache 2.0)
 * [Firebase Messaging Example](https://github.com/firebase/quickstart-android/blob/7147f60451b3eeaaa05fc31208ffb67e2df73c3c/messaging/app/src/main/java/com/google/firebase/quickstart/fcm/kotlin/MyFirebaseMessagingService.kt) (Apache 2.0)
 * [Designing a logo with Inkscape](https://www.youtube.com/watch?v=r2Kv61cd2P4)
-
-Thanks to these projects for allowing me to copy-paste a lot.
+* [Foreground service](https://robertohuertas.com/2019/06/29/android_foreground_services/)

app/schemas/io.heckel.ntfy.data.Database/2.json

@@ -2,11 +2,11 @@
   "formatVersion": 1,
   "database": {
     "version": 2,
-    "identityHash": "30177aa8688290d24499babf22b15720",
+    "identityHash": "df0a0eab3fc3056bf12e04a09c084660",
     "entities": [
       {
         "tableName": "Subscription",
-        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER NOT NULL, `baseUrl` TEXT NOT NULL, `topic` TEXT NOT NULL, PRIMARY KEY(`id`))",
+        "createSql": "CREATE TABLE IF NOT EXISTS `${TABLE_NAME}` (`id` INTEGER NOT NULL, `baseUrl` TEXT NOT NULL, `topic` TEXT NOT NULL, `instant` INTEGER NOT NULL, PRIMARY KEY(`id`))",
         "fields": [
           {
             "fieldPath": "id",
@@ -25,6 +25,12 @@
             "columnName": "topic",
             "affinity": "TEXT",
             "notNull": true
+          },
+          {
+            "fieldPath": "instant",
+            "columnName": "instant",
+            "affinity": "INTEGER",
+            "notNull": true
           }
         ],
         "primaryKey": {
@@ -94,7 +100,7 @@
     "views": [],
     "setupQueries": [
       "CREATE TABLE IF NOT EXISTS room_master_table (id INTEGER PRIMARY KEY,identity_hash TEXT)",
-      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, '30177aa8688290d24499babf22b15720')"
+      "INSERT OR REPLACE INTO room_master_table (id,identity_hash) VALUES(42, 'df0a0eab3fc3056bf12e04a09c084660')"
     ]
   }
 }

app/src/main/AndroidManifest.xml

@@ -1,9 +1,21 @@
 <?xml version="1.0" encoding="utf-8"?>
 <manifest xmlns:android="http://schemas.android.com/apk/res/android"
           package="io.heckel.ntfy">
-    <!-- Permissions -->
-    <uses-permission android:name="android.permission.INTERNET"/>
+    <!--
+         Permissions
+         - FOREGROUND_SERVICE is needed to support "use another server" feature
+         - WAKE_LOCK & RECEIVE_BOOT_COMPLETED are required to restart the foreground service
+           if it is stopped; see https://robertohuertas.com/2019/06/29/android_foreground_services/
+    -->
+    <uses-permission android:name="android.permission.INTERNET" />
+    <uses-permission android:name="android.permission.FOREGROUND_SERVICE" />
+    <uses-permission android:name="android.permission.WAKE_LOCK" />
+    <uses-permission android:name="android.permission.RECEIVE_BOOT_COMPLETED"/>
 
+    <!--
+         Application
+         - usesCleartextTraffic is required to support "use another server" feature
+    -->
     <application
             android:name=".app.Application"
             android:allowBackup="true"
@@ -11,7 +23,8 @@
             android:label="@string/app_name"
             android:roundIcon="@mipmap/ic_launcher_round"
             android:supportsRtl="true"
-            android:theme="@style/AppTheme">
+            android:theme="@style/AppTheme"
+            android:usesCleartextTraffic="true">
 
         <!-- Main activity -->
         <activity
@@ -33,6 +46,9 @@
                     android:value=".ui.MainActivity" />
         </activity>
 
+        <!-- Subscriber foreground service for hosts other than ntfy.sh -->
+        <service android:name=".msg.SubscriberService" />
+
         <!-- Firebase messaging -->
         <service
                 android:name=".msg.FirebaseService"

app/src/main/java/io/heckel/ntfy/data/Database.kt

@@ -13,16 +13,18 @@ data class Subscription(
     @PrimaryKey val id: Long, // Internal ID, only used in Repository and activities
     @ColumnInfo(name = "baseUrl") val baseUrl: String,
     @ColumnInfo(name = "topic") val topic: String,
+    @ColumnInfo(name = "instant") val instant: Boolean,
     @Ignore val notifications: Int,
     @Ignore val lastActive: Long = 0 // Unix timestamp
 ) {
-    constructor(id: Long, baseUrl: String, topic: String) : this(id, baseUrl, topic, 0, 0)
+    constructor(id: Long, baseUrl: String, topic: String, instant: Boolean) : this(id, baseUrl, topic, instant, 0, 0)
 }
 
 data class SubscriptionWithMetadata(
     val id: Long,
     val baseUrl: String,
     val topic: String,
+    val instant: Boolean,
     val notifications: Int,
     val lastActive: Long
 )
@@ -60,7 +62,7 @@ abstract class Database : RoomDatabase() {
         private val MIGRATION_1_2 = object : Migration(1, 2) {
             override fun migrate(db: SupportSQLiteDatabase) {
                 // Drop "notifications" & "lastActive" columns (SQLite does not support dropping columns, ...)
-                db.execSQL("CREATE TABLE Subscription_New (id INTEGER NOT NULL, baseUrl TEXT NOT NULL, topic TEXT NOT NULL, PRIMARY KEY(id))")
+                db.execSQL("CREATE TABLE Subscription_New (id INTEGER NOT NULL, baseUrl TEXT NOT NULL, topic TEXT NOT NULL, instant INTEGER NOT NULL DEFAULT('0'), PRIMARY KEY(id))")
                 db.execSQL("INSERT INTO Subscription_New SELECT id, baseUrl, topic FROM Subscription")
                 db.execSQL("DROP TABLE Subscription")
                 db.execSQL("ALTER TABLE Subscription_New RENAME TO Subscription")
@@ -76,7 +78,7 @@ abstract class Database : RoomDatabase() {
 @Dao
 interface SubscriptionDao {
     @Query(
-        "SELECT s.id, s.baseUrl, s.topic, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
+        "SELECT s.id, s.baseUrl, s.topic, s.instant, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
         "FROM subscription AS s " +
         "LEFT JOIN notification AS n ON s.id=n.subscriptionId AND n.deleted != 1 " +
         "GROUP BY s.id " +
@@ -85,7 +87,7 @@ interface SubscriptionDao {
     fun listFlow(): Flow<List<SubscriptionWithMetadata>>
 
     @Query(
-        "SELECT s.id, s.baseUrl, s.topic, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
+        "SELECT s.id, s.baseUrl, s.topic, s.instant, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
         "FROM subscription AS s " +
         "LEFT JOIN notification AS n ON s.id=n.subscriptionId AND n.deleted != 1 " +
         "GROUP BY s.id " +
@@ -94,7 +96,7 @@ interface SubscriptionDao {
     fun list(): List<SubscriptionWithMetadata>
 
     @Query(
-        "SELECT s.id, s.baseUrl, s.topic, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
+        "SELECT s.id, s.baseUrl, s.topic, s.instant, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
         "FROM subscription AS s " +
         "LEFT JOIN notification AS n ON s.id=n.subscriptionId AND n.deleted != 1 " +
         "WHERE s.baseUrl = :baseUrl AND s.topic = :topic " +
@@ -103,7 +105,7 @@ interface SubscriptionDao {
     fun get(baseUrl: String, topic: String): SubscriptionWithMetadata?
 
     @Query(
-        "SELECT s.id, s.baseUrl, s.topic, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
+        "SELECT s.id, s.baseUrl, s.topic, s.instant, COUNT(n.id) notifications, IFNULL(MAX(n.timestamp),0) AS lastActive " +
         "FROM subscription AS s " +
         "LEFT JOIN notification AS n ON s.id=n.subscriptionId AND n.deleted != 1 " +
         "WHERE s.id = :subscriptionId " +

app/src/main/java/io/heckel/ntfy/data/Repository.kt

@@ -19,6 +19,13 @@ class Repository(private val subscriptionDao: SubscriptionDao, private val notif
             .map { list -> toSubscriptionList(list) }
     }
 
+    fun getSubscriptionIdsLiveData(): LiveData<Set<Long>> {
+        return subscriptionDao
+            .listFlow()
+            .asLiveData()
+            .map { list -> list.map { it.id }.toSet() }
+    }
+
     fun getSubscriptions(): List<Subscription> {
         return toSubscriptionList(subscriptionDao.list())
     }
@@ -52,11 +59,13 @@ class Repository(private val subscriptionDao: SubscriptionDao, private val notif
 
     @Suppress("RedundantSuspendModifier")
     @WorkerThread
-    suspend fun addNotification(notification: Notification) {
+    suspend fun addNotification(notification: Notification): Boolean {
         val maybeExistingNotification = notificationDao.get(notification.id)
         if (maybeExistingNotification == null) {
             notificationDao.add(notification)
+            return true
         }
+        return false
     }
 
     @Suppress("RedundantSuspendModifier")
@@ -77,6 +86,7 @@ class Repository(private val subscriptionDao: SubscriptionDao, private val notif
                 id = s.id,
                 baseUrl = s.baseUrl,
                 topic = s.topic,
+                instant = s.instant,
                 lastActive = s.lastActive,
                 notifications = s.notifications
             )
@@ -91,6 +101,7 @@ class Repository(private val subscriptionDao: SubscriptionDao, private val notif
             id = s.id,
             baseUrl = s.baseUrl,
             topic = s.topic,
+            instant = s.instant,
             lastActive = s.lastActive,
             notifications = s.notifications
         )

app/src/main/java/io/heckel/ntfy/data/Util.kt

@@ -1,6 +1,7 @@
 package io.heckel.ntfy.data
 
 fun topicUrl(baseUrl: String, topic: String) = "${baseUrl}/${topic}"
+fun topicUrlJson(baseUrl: String, topic: String, since: String) = "${topicUrl(baseUrl, topic)}/json?since=$since"
 fun topicUrlJsonPoll(baseUrl: String, topic: String) = "${topicUrl(baseUrl, topic)}/json?poll=1"
 fun topicShortUrl(baseUrl: String, topic: String) =
     topicUrl(baseUrl, topic)

app/src/main/java/io/heckel/ntfy/msg/ApiService.kt

@@ -4,19 +4,24 @@ import android.util.Log
 import com.google.gson.Gson
 import io.heckel.ntfy.data.Notification
 import io.heckel.ntfy.data.topicUrl
+import io.heckel.ntfy.data.topicUrlJson
 import io.heckel.ntfy.data.topicUrlJsonPoll
-import okhttp3.OkHttpClient
-import okhttp3.Request
+import okhttp3.*
 import okhttp3.RequestBody.Companion.toRequestBody
+import java.io.IOException
 import java.util.concurrent.TimeUnit
 
 class ApiService {
     private val gson = Gson()
     private val client = OkHttpClient.Builder()
-        .callTimeout(10, TimeUnit.SECONDS) // Total timeout for entire request
-        .connectTimeout(10, TimeUnit.SECONDS)
-        .readTimeout(10, TimeUnit.SECONDS)
-        .writeTimeout(10, TimeUnit.SECONDS)
+        .callTimeout(15, TimeUnit.SECONDS) // Total timeout for entire request
+        .connectTimeout(15, TimeUnit.SECONDS)
+        .readTimeout(15, TimeUnit.SECONDS)
+        .writeTimeout(15, TimeUnit.SECONDS)
+        .build()
+
+    private val subscriberClient = OkHttpClient.Builder()
+        .readTimeout(77, TimeUnit.SECONDS) // Assuming that keepalive messages are more frequent than this
         .build()
 
     fun publish(baseUrl: String, topic: String, message: String) {
@@ -51,18 +56,53 @@ class ApiService {
         }
     }
 
+    fun subscribe(subscriptionId: Long, baseUrl: String, topic: String, since: Long, notify: (Notification) -> Unit, fail: (Exception) -> Unit): Call {
+        val sinceVal = if (since == 0L) "all" else since.toString()
+        val url = topicUrlJson(baseUrl, topic, sinceVal)
+        Log.d(TAG, "Opening subscription connection to $url")
+
+        val request = Request.Builder().url(url).build()
+        val call = subscriberClient.newCall(request)
+        call.enqueue(object : Callback {
+            override fun onResponse(call: Call, response: Response) {
+                try {
+                    if (!response.isSuccessful) {
+                        throw Exception("Unexpected response ${response.code} when subscribing to topic $url")
+                    }
+                    val source = response.body?.source() ?: throw Exception("Unexpected response for $url: body is empty")
+                    while (!source.exhausted()) {
+                        val line = source.readUtf8Line() ?: throw Exception("Unexpected response for $url: line is null")
+                        val message = gson.fromJson(line, Message::class.java)
+                        if (message.event == EVENT_MESSAGE) {
+                            val notification = Notification(message.id, subscriptionId, message.time, message.message, false)
+                            notify(notification)
+                        }
+                    }
+                } catch (e: Exception) {
+                    fail(e)
+                }
+            }
+            override fun onFailure(call: Call, e: IOException) {
+                fail(e)
+            }
+        })
+        return call
+    }
+
     private fun fromString(subscriptionId: Long, s: String): Notification {
-        val n = gson.fromJson(s, NotificationData::class.java) // Indirection to prevent accidental field renames, etc.
+        val n = gson.fromJson(s, Message::class.java)
         return Notification(n.id, subscriptionId, n.time, n.message, false)
     }
 
-    private data class NotificationData(
+    private data class Message(
         val id: String,
         val time: Long,
+        val event: String,
         val message: String
     )
 
     companion object {
         private const val TAG = "NtfyApiService"
+        private const val EVENT_MESSAGE = "message"
     }
 }

app/src/main/java/io/heckel/ntfy/msg/FirebaseService.kt

@@ -9,7 +9,6 @@ import io.heckel.ntfy.data.Notification
 import kotlinx.coroutines.CoroutineScope
 import kotlinx.coroutines.SupervisorJob
 import kotlinx.coroutines.launch
-import java.util.*
 
 class FirebaseService : FirebaseMessagingService() {
     private val repository by lazy { (application as Application).repository }
@@ -40,11 +39,13 @@ class FirebaseService : FirebaseMessagingService() {
             // Add notification
             val subscription = repository.getSubscription(baseUrl, topic) ?: return@launch
             val notification = Notification(id = id, subscriptionId = subscription.id, timestamp = timestamp, message = message, deleted = false)
-            repository.addNotification(notification)
+            val added = repository.addNotification(notification)
 
-            // Send notification
-            Log.d(TAG, "Sending notification for message: from=${remoteMessage.from}, data=${data}")
-            notifier.send(subscription, message)
+            // Send notification (only if it's not already known)
+            if (added) {
+                Log.d(TAG, "Sending notification for message: from=${remoteMessage.from}, data=${data}")
+                notifier.send(subscription, message)
+            }
         }
     }
 

app/src/main/java/io/heckel/ntfy/msg/NotificationService.kt

@@ -10,23 +10,17 @@ import android.media.RingtoneManager
 import android.os.Build
 import android.util.Log
 import androidx.core.app.NotificationCompat
-import com.google.firebase.messaging.FirebaseMessagingService
-import com.google.firebase.messaging.RemoteMessage
 import io.heckel.ntfy.R
-import io.heckel.ntfy.app.Application
-import io.heckel.ntfy.data.*
+import io.heckel.ntfy.data.Subscription
+import io.heckel.ntfy.data.topicShortUrl
 import io.heckel.ntfy.ui.DetailActivity
 import io.heckel.ntfy.ui.MainActivity
-import kotlinx.coroutines.CoroutineScope
-import kotlinx.coroutines.SupervisorJob
-import kotlinx.coroutines.launch
-import java.util.*
 import kotlin.random.Random
 
 class NotificationService(val context: Context) {
     fun send(subscription: Subscription, message: String) {
         val title = topicShortUrl(subscription.baseUrl, subscription.topic)
-        Log.d(TAG, "Sending notification $title: $message")
+        Log.d(TAG, "Displaying notification $title: $message")
 
         // Create an Intent for the activity you want to start
         val intent = Intent(context, DetailActivity::class.java)
@@ -38,9 +32,8 @@ class NotificationService(val context: Context) {
             getPendingIntent(0, PendingIntent.FLAG_UPDATE_CURRENT) // Get the PendingIntent containing the entire back stack
         }
 
-        val channelId = context.getString(R.string.notification_channel_id)
         val defaultSoundUri = RingtoneManager.getDefaultUri(RingtoneManager.TYPE_NOTIFICATION)
-        val notificationBuilder = NotificationCompat.Builder(context, channelId)
+        val notificationBuilder = NotificationCompat.Builder(context, CHANNEL_ID)
             .setSmallIcon(R.drawable.ic_notification_icon)
             .setContentTitle(title)
             .setContentText(message)
@@ -50,8 +43,8 @@ class NotificationService(val context: Context) {
 
         val notificationManager = context.getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
         if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
-            val channelName = context.getString(R.string.notification_channel_name)
-            val channel = NotificationChannel(channelId, channelName, NotificationManager.IMPORTANCE_DEFAULT)
+            val channelName = context.getString(R.string.channel_notifications_name) // Show's up in UI
+            val channel = NotificationChannel(CHANNEL_ID, channelName, NotificationManager.IMPORTANCE_DEFAULT)
             notificationManager.createNotificationChannel(channel)
         }
         notificationManager.notify(Random.nextInt(), notificationBuilder.build())
@@ -59,5 +52,6 @@ class NotificationService(val context: Context) {
 
     companion object {
         private const val TAG = "NtfyNotificationService"
+        private const val CHANNEL_ID = "ntfy"
     }
 }

app/src/main/java/io/heckel/ntfy/msg/SubscriberService.kt

@@ -0,0 +1,259 @@
+package io.heckel.ntfy.msg
+
+import android.app.*
+import android.content.Context
+import android.content.Intent
+import android.os.Build
+import android.os.IBinder
+import android.os.PowerManager
+import android.os.SystemClock
+import android.util.Log
+import androidx.core.app.NotificationCompat
+import io.heckel.ntfy.R
+import io.heckel.ntfy.app.Application
+import io.heckel.ntfy.data.Subscription
+import io.heckel.ntfy.data.topicUrl
+import io.heckel.ntfy.ui.MainActivity
+import kotlinx.coroutines.*
+import okhttp3.Call
+import java.util.concurrent.ConcurrentHashMap
+import java.util.concurrent.atomic.AtomicBoolean
+
+/**
+ *
+ * Largely modeled after this fantastic resource:
+ * - https://robertohuertas.com/2019/06/29/android_foreground_services/
+ * - https://github.com/robertohuertasm/endless-service/blob/master/app/src/main/java/com/robertohuertas/endless/EndlessService.kt
+ */
+class SubscriberService : Service() {
+    private var wakeLock: PowerManager.WakeLock? = null
+    private var isServiceStarted = false
+    private val repository by lazy { (application as Application).repository }
+    private val jobs = ConcurrentHashMap<Long, Job>() // Subscription ID -> Job
+    private val calls = ConcurrentHashMap<Long, Call>() // Subscription ID -> Cal
+    private val api = ApiService()
+    private val notifier = NotificationService(this)
+
+    override fun onBind(intent: Intent): IBinder? {
+        return null // We don't provide binding, so return null
+    }
+
+    override fun onStartCommand(intent: Intent?, flags: Int, startId: Int): Int {
+        Log.d(TAG, "onStartCommand executed with startId: $startId")
+        if (intent != null) {
+            val action = intent.action
+            Log.d(TAG, "using an intent with action $action")
+            when (action) {
+                Actions.START.name -> startService()
+                Actions.STOP.name -> stopService()
+                else -> Log.e(TAG, "This should never happen. No action in the received intent")
+            }
+        } else {
+            Log.d(TAG, "with a null intent. It has been probably restarted by the system.")
+        }
+        return START_STICKY // restart if system kills the service
+    }
+
+    override fun onCreate() {
+        super.onCreate()
+        Log.d(TAG, "The service has been created".toUpperCase())
+        val notification = createNotification()
+        startForeground(SERVICE_ID, notification)
+    }
+
+    override fun onDestroy() {
+        super.onDestroy()
+        Log.d(TAG, "The service has been destroyed".toUpperCase())
+    }
+
+    override fun onTaskRemoved(rootIntent: Intent) {
+        val restartServiceIntent = Intent(applicationContext, SubscriberService::class.java).also {
+            it.setPackage(packageName)
+        };
+        val restartServicePendingIntent: PendingIntent = PendingIntent.getService(this, 1, restartServiceIntent, PendingIntent.FLAG_ONE_SHOT);
+        applicationContext.getSystemService(Context.ALARM_SERVICE);
+        val alarmService: AlarmManager = applicationContext.getSystemService(Context.ALARM_SERVICE) as AlarmManager;
+        alarmService.set(AlarmManager.ELAPSED_REALTIME, SystemClock.elapsedRealtime() + 1000, restartServicePendingIntent);
+    }
+
+    private fun startService() {
+        if (isServiceStarted) {
+            launchOrCancelJobs()
+            return
+        }
+        Log.d(TAG, "Starting the foreground service task")
+        isServiceStarted = true
+        saveServiceState(this, ServiceState.STARTED)
+        wakeLock = (getSystemService(Context.POWER_SERVICE) as PowerManager).run {
+            newWakeLock(PowerManager.PARTIAL_WAKE_LOCK, WAKE_LOCK_TAG).apply {
+                acquire()
+            }
+        }
+        launchOrCancelJobs()
+    }
+
+    private fun stopService() {
+        Log.d(TAG, "Stopping the foreground service")
+
+        // Cancelling all remaining jobs and open HTTP calls
+        jobs.values.forEach { job -> job.cancel() }
+        calls.values.forEach { call -> call.cancel() }
+        jobs.clear()
+        calls.clear()
+
+        // Releasing wake-lock and stopping ourselves
+        try {
+            wakeLock?.let {
+                if (it.isHeld) {
+                    it.release()
+                }
+            }
+            stopForeground(true)
+            stopSelf()
+        } catch (e: Exception) {
+            Log.d(TAG, "Service stopped without being started: ${e.message}")
+        }
+
+        isServiceStarted = false
+        saveServiceState(this, ServiceState.STOPPED)
+    }
+
+    private fun launchOrCancelJobs() = GlobalScope.launch(Dispatchers.IO) {
+        val subscriptions = repository.getSubscriptions().filter { s -> s.instant }
+        val subscriptionIds = subscriptions.map { it.id }
+        Log.d(TAG, "Starting/stopping jobs for current subscriptions")
+        Log.d(TAG, "- Subscriptions: $subscriptions")
+        Log.d(TAG, "- Jobs: $jobs")
+        Log.d(TAG, "- HTTP calls: $calls")
+        subscriptions.forEach { subscription ->
+            if (!jobs.containsKey(subscription.id)) {
+                Log.d(TAG, "Starting job for $subscription")
+                jobs[subscription.id] = launchJob(this, subscription)
+            }
+        }
+        jobs.keys().toList().forEach { subscriptionId ->
+            if (!subscriptionIds.contains(subscriptionId)) {
+                Log.d(TAG, "Cancelling job for $subscriptionId")
+                val job = jobs.remove(subscriptionId)
+                val call = calls.remove(subscriptionId)
+                job?.cancel()
+                call?.cancel()
+            }
+        }
+    }
+
+    private fun launchJob(scope: CoroutineScope, subscription: Subscription): Job = scope.launch(Dispatchers.IO) {
+        val url = topicUrl(subscription.baseUrl, subscription.topic)
+        Log.d(TAG, "[$url] Starting connection job")
+        var since = 0L
+        var retryMillis = 0L
+        while (isActive && isServiceStarted) {
+            Log.d(TAG, "[$url] (Re-)starting subscription for $subscription")
+            val startTime = System.currentTimeMillis()
+
+            try {
+                val failed = AtomicBoolean(false)
+                val notify = { n: io.heckel.ntfy.data.Notification ->
+                    Log.d(TAG, "[$url] Received new notification: $n")
+                    since = n.timestamp
+                    scope.launch(Dispatchers.IO) {
+                        val added = repository.addNotification(n)
+                        if (added) {
+                            Log.d(TAG, "[$url] Showing notification: $n")
+                            notifier.send(subscription, n.message)
+                        }
+                    }
+                    Unit
+                }
+                val fail = { e: Exception ->
+                    Log.e(TAG, "[$url] Connection failed (1): ${e.message}", e)
+                    failed.set(true)
+                }
+                val call = api.subscribe(subscription.id, subscription.baseUrl, subscription.topic, since, notify, fail)
+                calls[subscription.id] = call
+                while (!failed.get() && !call.isCanceled() && isActive && isServiceStarted) {
+                    Log.d(TAG, "[$url] Connection is active (failed=$failed, callCanceled=${call.isCanceled()}, jobActive=$isActive, serviceStarted=$isServiceStarted")
+                    delay(CONNECTION_LOOP_DELAY_MILLIS) // Resumes immediately if job is cancelled
+                }
+            } catch (e: Exception) {
+                Log.e(TAG, "[$url] Connection failed (2): ${e.message}", e)
+            }
+            if (isActive && isServiceStarted) {
+                val connectionDurationMillis = System.currentTimeMillis() - startTime
+                if (connectionDurationMillis > RETRY_RESET_AFTER_MILLIS) {
+                    retryMillis = RETRY_STEP_MILLIS
+                } else if (retryMillis + RETRY_STEP_MILLIS >= RETRY_MAX_MILLIS) {
+                    retryMillis = RETRY_MAX_MILLIS
+                } else {
+                    retryMillis += RETRY_STEP_MILLIS
+                }
+                Log.d(TAG, "Connection failed, retrying connection in ${retryMillis/1000}s ...")
+                delay(retryMillis)
+            }
+        }
+        Log.d(TAG, "[$url] Connection job SHUT DOWN")
+    }
+
+    private fun createNotification(): Notification {
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            val notificationManager = getSystemService(Context.NOTIFICATION_SERVICE) as NotificationManager
+            val channelName = getString(R.string.channel_subscriber_service_name) // Show's up in UI
+            val channel = NotificationChannel(CHANNEL_ID, channelName, NotificationManager.IMPORTANCE_LOW).let {
+                it.setShowBadge(false) // Don't show long-press badge
+                it
+            }
+            notificationManager.createNotificationChannel(channel)
+        }
+
+        val pendingIntent: PendingIntent = Intent(this, MainActivity::class.java).let { notificationIntent ->
+            PendingIntent.getActivity(this, 0, notificationIntent, 0)
+        }
+
+        val title = getString(R.string.channel_subscriber_notification_title)
+        val text = getString(R.string.channel_subscriber_notification_text)
+        return NotificationCompat.Builder(this, CHANNEL_ID)
+            .setSmallIcon(R.drawable.ic_notification_icon)
+            .setContentTitle(title)
+            .setContentText(text)
+            .setContentIntent(pendingIntent)
+            .setSound(null)
+            .setShowWhen(false) // Don't show date/time
+            .build()
+    }
+
+    enum class Actions {
+        START,
+        STOP
+    }
+
+    enum class ServiceState {
+        STARTED,
+        STOPPED,
+    }
+
+    companion object {
+        private const val TAG = "NtfySubscriberService"
+        private const val WAKE_LOCK_TAG = "SubscriberService:lock"
+        private const val CHANNEL_ID = "ntfy-subscriber"
+        private const val SERVICE_ID = 2586
+        private const val SHARED_PREFS_ID = "SubscriberService"
+        private const val SHARED_PREFS_SERVICE_STATE = "ServiceState"
+        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 = 30_000L
+
+        fun saveServiceState(context: Context, state: ServiceState) {
+            val sharedPrefs = context.getSharedPreferences(SHARED_PREFS_ID, Context.MODE_PRIVATE)
+            sharedPrefs.edit()
+                .putString(SHARED_PREFS_SERVICE_STATE, state.name)
+                .apply()
+        }
+
+        fun readServiceState(context: Context): ServiceState {
+            val sharedPrefs = context.getSharedPreferences(SHARED_PREFS_ID, Context.MODE_PRIVATE)
+            val value = sharedPrefs.getString(SHARED_PREFS_SERVICE_STATE, ServiceState.STOPPED.name)
+            return ServiceState.valueOf(value!!)
+        }
+    }
+}

app/src/main/java/io/heckel/ntfy/ui/AddFragment.kt

@@ -20,10 +20,13 @@ import io.heckel.ntfy.data.Repository
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 
-class AddFragment(private val viewModel: SubscriptionsViewModel, private val onSubscribe: (topic: String, baseUrl: String) -> Unit) : DialogFragment() {
+class AddFragment(private val viewModel: SubscriptionsViewModel, private val onSubscribe: (topic: String, baseUrl: String, instant: Boolean) -> Unit) : DialogFragment() {
     private lateinit var topicNameText: TextInputEditText
     private lateinit var baseUrlText: TextInputEditText
     private lateinit var useAnotherServerCheckbox: CheckBox
+    private lateinit var useAnotherServerDescription: View
+    private lateinit var instantDeliveryCheckbox: CheckBox
+    private lateinit var instantDeliveryDescription: View
     private lateinit var subscribeButton: Button
 
     override fun onCreateDialog(savedInstanceState: Bundle?): Dialog {
@@ -32,10 +35,10 @@ class AddFragment(private val viewModel: SubscriptionsViewModel, private val onS
             val view = requireActivity().layoutInflater.inflate(R.layout.add_dialog_fragment, null)
             topicNameText = view.findViewById(R.id.add_dialog_topic_text) as TextInputEditText
             baseUrlText = view.findViewById(R.id.add_dialog_base_url_text) as TextInputEditText
+            instantDeliveryCheckbox = view.findViewById(R.id.add_dialog_instant_delivery_checkbox) as CheckBox
+            instantDeliveryDescription = view.findViewById(R.id.add_dialog_instant_delivery_description)
             useAnotherServerCheckbox = view.findViewById(R.id.add_dialog_use_another_server_checkbox) as CheckBox
-
-            // FIXME For now, other servers are disabled
-            useAnotherServerCheckbox.visibility = View.GONE
+            useAnotherServerDescription = view.findViewById(R.id.add_dialog_use_another_server_description)
 
             // Build dialog
             val alert = AlertDialog.Builder(it)
@@ -43,7 +46,8 @@ class AddFragment(private val viewModel: SubscriptionsViewModel, private val onS
                 .setPositiveButton(R.string.add_dialog_button_subscribe) { _, _ ->
                     val topic = topicNameText.text.toString()
                     val baseUrl = getBaseUrl()
-                    onSubscribe(topic, baseUrl)
+                    val instant = if (useAnotherServerCheckbox.isChecked) true else instantDeliveryCheckbox.isChecked
+                    onSubscribe(topic, baseUrl, instant)
                 }
                 .setNegativeButton(R.string.add_dialog_button_cancel) { _, _ ->
                     dialog?.cancel()
@@ -70,9 +74,23 @@ class AddFragment(private val viewModel: SubscriptionsViewModel, private val onS
                 }
                 topicNameText.addTextChangedListener(textWatcher)
                 baseUrlText.addTextChangedListener(textWatcher)
+                instantDeliveryCheckbox.setOnCheckedChangeListener { _, isChecked ->
+                    if (isChecked) instantDeliveryDescription.visibility = View.VISIBLE
+                    else instantDeliveryDescription.visibility = View.GONE
+                }
                 useAnotherServerCheckbox.setOnCheckedChangeListener { _, isChecked ->
-                    if (isChecked) baseUrlText.visibility = View.VISIBLE
-                    else baseUrlText.visibility = View.GONE
+                    if (isChecked) {
+                        useAnotherServerDescription.visibility = View.VISIBLE
+                        baseUrlText.visibility = View.VISIBLE
+                        instantDeliveryCheckbox.visibility = View.GONE
+                        instantDeliveryDescription.visibility = View.GONE
+                    } else {
+                        useAnotherServerDescription.visibility = View.GONE
+                        baseUrlText.visibility = View.GONE
+                        instantDeliveryCheckbox.visibility = View.VISIBLE
+                        if (instantDeliveryCheckbox.isChecked) instantDeliveryDescription.visibility = View.VISIBLE
+                        else instantDeliveryDescription.visibility = View.GONE
+                    }
                     validateInput()
                 }
             }

app/src/main/java/io/heckel/ntfy/ui/DetailActivity.kt

@@ -29,6 +29,8 @@ import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
 import java.util.*
 
+// TODO dismiss notifications when navigating to detail page
+
 class DetailActivity : AppCompatActivity(), ActionMode.Callback {
     private val viewModel by viewModels<DetailViewModel> {
         DetailViewModelFactory((application as Application).repository)
@@ -40,6 +42,7 @@ class DetailActivity : AppCompatActivity(), ActionMode.Callback {
     private var subscriptionId: Long = 0L // Set in onCreate()
     private var subscriptionBaseUrl: String = "" // Set in onCreate()
     private var subscriptionTopic: String = "" // Set in onCreate()
+    private var subscriptionInstant: Boolean = false // Set in onCreate()
 
     // Action mode stuff
     private lateinit var mainList: RecyclerView
@@ -59,6 +62,7 @@ class DetailActivity : AppCompatActivity(), ActionMode.Callback {
         subscriptionId = intent.getLongExtra(MainActivity.EXTRA_SUBSCRIPTION_ID, 0)
         subscriptionBaseUrl = intent.getStringExtra(MainActivity.EXTRA_SUBSCRIPTION_BASE_URL) ?: return
         subscriptionTopic = intent.getStringExtra(MainActivity.EXTRA_SUBSCRIPTION_TOPIC) ?: return
+        subscriptionInstant = intent.getBooleanExtra(MainActivity.EXTRA_SUBSCRIPTION_INSTANT, false)
 
         // Set title
         val subscriptionBaseUrl = intent.getStringExtra(MainActivity.EXTRA_SUBSCRIPTION_BASE_URL) ?: return
@@ -134,9 +138,11 @@ class DetailActivity : AppCompatActivity(), ActionMode.Callback {
                 val message = getString(R.string.detail_test_message, Date().toString())
                 api.publish(subscriptionBaseUrl, subscriptionTopic, message)
             } catch (e: Exception) {
-                Toast
-                    .makeText(this@DetailActivity, getString(R.string.detail_test_message_error, e.message), Toast.LENGTH_LONG)
-                    .show()
+                runOnUiThread {
+                    Toast
+                        .makeText(this@DetailActivity, getString(R.string.detail_test_message_error, e.message), Toast.LENGTH_LONG)
+                        .show()
+                }
             }
         }
     }
@@ -168,9 +174,11 @@ class DetailActivity : AppCompatActivity(), ActionMode.Callback {
                 newNotifications.forEach { notification -> repository.addNotification(notification) }
                 runOnUiThread { Toast.makeText(this@DetailActivity, toastMessage, Toast.LENGTH_LONG).show() }
             } catch (e: Exception) {
-                Toast
-                    .makeText(this@DetailActivity, getString(R.string.refresh_message_error, e.message), Toast.LENGTH_LONG)
-                    .show()
+                runOnUiThread {
+                    Toast
+                        .makeText(this@DetailActivity, getString(R.string.refresh_message_error, e.message), Toast.LENGTH_LONG)
+                        .show()
+                }
             }
         }
     }
@@ -185,7 +193,9 @@ class DetailActivity : AppCompatActivity(), ActionMode.Callback {
                 // Return to main activity
                 val result = Intent()
                     .putExtra(MainActivity.EXTRA_SUBSCRIPTION_ID, subscriptionId)
+                    .putExtra(MainActivity.EXTRA_SUBSCRIPTION_BASE_URL, subscriptionBaseUrl)
                     .putExtra(MainActivity.EXTRA_SUBSCRIPTION_TOPIC, subscriptionTopic)
+                    .putExtra(MainActivity.EXTRA_SUBSCRIPTION_INSTANT, subscriptionInstant)
                 setResult(RESULT_OK, result)
                 finish()
 

app/src/main/java/io/heckel/ntfy/ui/MainActivity.kt

@@ -6,6 +6,7 @@ import android.app.AlertDialog
 import android.content.Context
 import android.content.Intent
 import android.net.Uri
+import android.os.Build
 import android.os.Bundle
 import android.util.Log
 import android.view.ActionMode
@@ -26,6 +27,10 @@ import io.heckel.ntfy.data.Subscription
 import io.heckel.ntfy.data.topicShortUrl
 import io.heckel.ntfy.msg.ApiService
 import io.heckel.ntfy.msg.NotificationService
+import io.heckel.ntfy.msg.SubscriberService
+import io.heckel.ntfy.msg.SubscriberService.ServiceState
+import io.heckel.ntfy.msg.SubscriberService.Actions
+import io.heckel.ntfy.msg.SubscriberService.Companion.readServiceState
 import io.heckel.ntfy.work.PollWorker
 import kotlinx.coroutines.Dispatchers
 import kotlinx.coroutines.launch
@@ -88,14 +93,23 @@ class MainActivity : AppCompatActivity(), ActionMode.Callback {
             }
         }
 
-        // Kick off periodic polling
-        val sharedPref = getSharedPreferences(SHARED_PREFS_ID, Context.MODE_PRIVATE)
-        val workPolicy = if (sharedPref.getInt(SHARED_PREFS_POLL_WORKER_VERSION, 0) == PollWorker.VERSION) {
+        viewModel.listIds().observe(this) {
+            maybeStartOrStopSubscriberService()
+        }
+
+        // Background things
+        startPeriodicWorker()
+        maybeStartOrStopSubscriberService()
+    }
+
+    private fun startPeriodicWorker() {
+        val sharedPrefs = getSharedPreferences(SHARED_PREFS_ID, Context.MODE_PRIVATE)
+        val workPolicy = if (sharedPrefs.getInt(SHARED_PREFS_POLL_WORKER_VERSION, 0) == PollWorker.VERSION) {
             Log.d(TAG, "Poll worker version matches: choosing KEEP as existing work policy")
             ExistingPeriodicWorkPolicy.KEEP
         } else {
             Log.d(TAG, "Poll worker version DOES NOT MATCH: choosing REPLACE as existing work policy")
-            sharedPref.edit()
+            sharedPrefs.edit()
                 .putInt(SHARED_PREFS_POLL_WORKER_VERSION, PollWorker.VERSION)
                 .apply()
             ExistingPeriodicWorkPolicy.REPLACE
@@ -135,12 +149,11 @@ class MainActivity : AppCompatActivity(), ActionMode.Callback {
     }
 
     private fun onSubscribeButtonClick() {
-        val newFragment = AddFragment(viewModel) { topic, baseUrl -> onSubscribe(topic, baseUrl) }
+        val newFragment = AddFragment(viewModel) { topic, baseUrl, instant -> onSubscribe(topic, baseUrl, instant) }
         newFragment.show(supportFragmentManager, "AddFragment")
     }
 
-    private fun onSubscribe(topic: String, baseUrl: String) {
-        // FIXME ignores baseUrl
+    private fun onSubscribe(topic: String, baseUrl: String, instant: Boolean) {
         Log.d(TAG, "Adding subscription ${topicShortUrl(baseUrl, topic)}")
 
         // Add subscription to database
@@ -148,21 +161,25 @@ class MainActivity : AppCompatActivity(), ActionMode.Callback {
             id = Random.nextLong(),
             baseUrl = baseUrl,
             topic = topic,
+            instant = instant,
             notifications = 0,
             lastActive = Date().time/1000
         )
         viewModel.add(subscription)
 
-        // Subscribe to Firebase topic
-        FirebaseMessaging
-            .getInstance()
-            .subscribeToTopic(topic)
-            .addOnCompleteListener {
-                Log.d(TAG, "Subscribing to topic complete: result=${it.result}, exception=${it.exception}, successful=${it.isSuccessful}")
-            }
-            .addOnFailureListener {
-                Log.e(TAG, "Subscribing to topic failed: $it")
-            }
+        // Subscribe to Firebase topic (instant subscriptions are triggered in observe())
+        if (!instant) {
+            Log.d(TAG, "Subscribing to Firebase")
+            FirebaseMessaging
+                .getInstance()
+                .subscribeToTopic(topic)
+                .addOnCompleteListener {
+                    Log.d(TAG, "Subscribing to topic complete: result=${it.result}, exception=${it.exception}, successful=${it.isSuccessful}")
+                }
+                .addOnFailureListener {
+                    Log.e(TAG, "Subscribing to topic failed: $it")
+                }
+        }
 
         // Fetch cached messages
         lifecycleScope.launch(Dispatchers.IO) {
@@ -222,6 +239,35 @@ class MainActivity : AppCompatActivity(), ActionMode.Callback {
         }
     }
 
+    private fun maybeStartOrStopSubscriberService() {
+        Log.d(TAG, "Triggering subscriber service refresh")
+        lifecycleScope.launch(Dispatchers.IO) {
+            val instantSubscriptions = repository.getSubscriptions().filter { s -> s.instant }
+            if (instantSubscriptions.isEmpty()) {
+                performActionOnSubscriberService(Actions.STOP)
+            } else {
+                performActionOnSubscriberService(Actions.START)
+            }
+        }
+    }
+
+    private fun performActionOnSubscriberService(action: Actions) {
+        val serviceState = readServiceState(this)
+        if (serviceState == ServiceState.STOPPED && action == Actions.STOP) {
+            return
+        }
+        val intent = Intent(this, SubscriberService::class.java)
+        intent.action = action.name
+        if (Build.VERSION.SDK_INT >= Build.VERSION_CODES.O) {
+            Log.d(TAG, "Performing SubscriberService action: ${action.name} (as foreground service, API >= 26)")
+            startForegroundService(intent)
+            return
+        } else {
+            Log.d(TAG, "Performing SubscriberService action: ${action.name} (as background service, API >= 26)")
+            startService(intent)
+        }
+    }
+
     private fun startDetailView(subscription: Subscription) {
         Log.d(TAG, "Entering detail view for subscription $subscription")
 
@@ -229,6 +275,7 @@ class MainActivity : AppCompatActivity(), ActionMode.Callback {
         intent.putExtra(EXTRA_SUBSCRIPTION_ID, subscription.id)
         intent.putExtra(EXTRA_SUBSCRIPTION_BASE_URL, subscription.baseUrl)
         intent.putExtra(EXTRA_SUBSCRIPTION_TOPIC, subscription.topic)
+        intent.putExtra(EXTRA_SUBSCRIPTION_INSTANT, subscription.instant)
         startActivityForResult(intent, REQUEST_CODE_DELETE_SUBSCRIPTION)
     }
 
@@ -236,10 +283,17 @@ class MainActivity : AppCompatActivity(), ActionMode.Callback {
         if (requestCode == REQUEST_CODE_DELETE_SUBSCRIPTION && resultCode == RESULT_OK) {
             val subscriptionId = data?.getLongExtra(EXTRA_SUBSCRIPTION_ID, 0)
             val subscriptionTopic = data?.getStringExtra(EXTRA_SUBSCRIPTION_TOPIC)
+            val subscriptionInstant = data?.getBooleanExtra(EXTRA_SUBSCRIPTION_INSTANT, false)
             Log.d(TAG, "Deleting subscription with subscription ID $subscriptionId (topic: $subscriptionTopic)")
 
             subscriptionId?.let { id -> viewModel.remove(id) }
-            subscriptionTopic?.let { topic -> FirebaseMessaging.getInstance().unsubscribeFromTopic(topic) } // FIXME This only works for ntfy.sh
+            subscriptionInstant?.let { instant ->
+                if (!instant) {
+                    Log.d(TAG, "Unsubscribing from Firebase")
+                    subscriptionTopic?.let { topic -> FirebaseMessaging.getInstance().unsubscribeFromTopic(topic) }
+                }
+                // Subscriber service changes are triggered in the observe() call above
+            }
         } else {
             super.onActivityResult(requestCode, resultCode, data)
         }
@@ -360,6 +414,7 @@ class MainActivity : AppCompatActivity(), ActionMode.Callback {
         const val EXTRA_SUBSCRIPTION_ID = "subscriptionId"
         const val EXTRA_SUBSCRIPTION_BASE_URL = "subscriptionBaseUrl"
         const val EXTRA_SUBSCRIPTION_TOPIC = "subscriptionTopic"
+        const val EXTRA_SUBSCRIPTION_INSTANT = "subscriptionInstant"
         const val REQUEST_CODE_DELETE_SUBSCRIPTION = 1
         const val ANIMATION_DURATION = 80L
         const val SHARED_PREFS_ID = "MainPreferences"

app/src/main/java/io/heckel/ntfy/ui/MainViewModel.kt

@@ -14,6 +14,10 @@ class SubscriptionsViewModel(private val repository: Repository) : ViewModel() {
         return repository.getSubscriptionsLiveData()
     }
 
+    fun listIds(): LiveData<Set<Long>> {
+        return repository.getSubscriptionIdsLiveData()
+    }
+
     fun add(subscription: Subscription) = viewModelScope.launch(Dispatchers.IO) {
         repository.addSubscription(subscription)
     }

app/src/main/java/io/heckel/ntfy/work/PollWorker.kt

@@ -2,11 +2,9 @@ package io.heckel.ntfy.work
 
 import android.content.Context
 import android.util.Log
-import android.widget.Toast
 import androidx.work.CoroutineWorker
 import androidx.work.WorkerParameters
 import io.heckel.ntfy.BuildConfig
-import io.heckel.ntfy.R
 import io.heckel.ntfy.data.Database
 import io.heckel.ntfy.data.Repository
 import io.heckel.ntfy.msg.ApiService

app/src/main/res/layout/add_dialog_fragment.xml

@@ -16,23 +16,42 @@
             android:textAlignment="viewStart"
             android:textAppearance="@style/TextAppearance.AppCompat.Large" android:paddingStart="4dp"/>
 
-    <com.google.android.material.textfield.TextInputEditText
-            android:id="@+id/add_dialog_topic_text"
-            android:layout_width="match_parent"
-            android:layout_height="wrap_content" android:hint="@string/add_dialog_topic_name_hint"
-            android:maxLines="1" android:inputType="text"/>
     <TextView
             android:text="@string/add_dialog_description_below"
             android:layout_width="match_parent"
             android:layout_height="wrap_content" android:id="@+id/add_dialog_description_below"
             android:paddingStart="4dp" android:paddingTop="3dp"/>
+    <com.google.android.material.textfield.TextInputEditText
+            android:id="@+id/add_dialog_topic_text"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" android:hint="@string/add_dialog_topic_name_hint"
+            android:maxLines="1" android:inputType="text" android:maxLength="64"/>
     <CheckBox
             android:text="@string/add_dialog_use_another_server"
             android:layout_width="match_parent"
-            android:layout_height="wrap_content" android:id="@+id/add_dialog_use_another_server_checkbox"/>
+            android:layout_height="wrap_content" android:id="@+id/add_dialog_use_another_server_checkbox"
+            android:layout_marginTop="-5dp" android:layout_marginBottom="-5dp" android:layout_marginStart="-3dp"/>
+    <TextView
+            android:text="@string/add_dialog_use_another_server_description"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" android:id="@+id/add_dialog_use_another_server_description"
+            android:paddingStart="4dp" android:paddingTop="0dp" android:layout_marginTop="-5dp"
+            android:visibility="gone"/>
     <com.google.android.material.textfield.TextInputEditText
             android:id="@+id/add_dialog_base_url_text"
             android:layout_width="match_parent"
             android:layout_height="wrap_content" android:visibility="gone"
-            android:hint="@string/app_base_url" android:inputType="textUri" android:maxLines="1"/>
+            android:hint="@string/app_base_url" android:inputType="textUri" android:maxLines="1"
+            android:layout_marginTop="-2dp" android:layout_marginBottom="5dp"/>
+    <CheckBox
+            android:text="@string/add_dialog_instant_delivery"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" android:id="@+id/add_dialog_instant_delivery_checkbox"
+            android:layout_marginTop="-8dp" android:layout_marginBottom="-5dp" android:layout_marginStart="-3dp"/>
+    <TextView
+            android:text="@string/add_dialog_instant_delivery_description"
+            android:layout_width="match_parent"
+            android:layout_height="wrap_content" android:id="@+id/add_dialog_instant_delivery_description"
+            android:paddingStart="4dp" android:paddingTop="0dp" android:layout_marginTop="-5dp"
+            android:visibility="gone"/>
 </LinearLayout>

app/src/main/res/values/strings.xml

@@ -3,9 +3,11 @@
     <string name="app_name">Ntfy</string>
     <string name="app_base_url">https://ntfy.sh</string> <!-- If changed, you must also change google-services.json! -->
 
-    <!-- Notifications -->
-    <string name="notification_channel_name">Ntfy</string>
-    <string name="notification_channel_id">ntfy</string>
+    <!-- Notification channels -->
+    <string name="channel_notifications_name">Notifications</string>
+    <string name="channel_subscriber_service_name">Subscription Service</string>
+    <string name="channel_subscriber_notification_title">Subscribed topics</string>
+    <string name="channel_subscriber_notification_text">Listening patiently for incoming notifications</string>
 
     <!-- Common refresh toasts -->
     <string name="refresh_message_result">%1$d notification(s) received</string>
@@ -38,6 +40,14 @@
     <string name="add_dialog_description_below">Topics are not password-protected, so choose a name that\'s not easy to guess. Once subscribed, you can PUT/POST to receive notifications on your phone.</string>
     <string name="add_dialog_topic_name_hint">Topic name, e.g. phils_alerts</string>
     <string name="add_dialog_use_another_server">Use another server</string>
+    <string name="add_dialog_use_another_server_description">
+        You can subscribe to topics from your own server. Due to platform limitations, this option requires a foreground
+        service and consumes more battery, but delivers notifications faster.
+    </string>
+    <string name="add_dialog_instant_delivery">Instant delivery (even in doze mode)</string>
+    <string name="add_dialog_instant_delivery_description">
+        Requires foreground service and consumes more battery, but delivers notifications faster.
+    </string>
     <string name="add_dialog_button_cancel">Cancel</string>
     <string name="add_dialog_button_subscribe">Subscribe</string>