Running code while streaming in background #419

helloagain-dev · 2019-01-30T13:35:14Z

I want to stream an icecast radio stream which works fine.
However, I also want to update the title/artist and cover regularly.
I can fetch this data from a REST API.

How can I run code that fetches this data every 10 seconds (or so) and updates the Player regularly?
Can I put a long-running task that does the fetch into TrackPlayer.registerPlaybackService?

The text was updated successfully, but these errors were encountered:

curiousdustin · 2019-01-30T15:08:35Z

Maybe not exactly what you want, but I'm using this to periodically check the state and progress of the player.

https://github.com/ocetnik/react-native-background-timer

helloagain-dev · 2019-01-30T15:13:11Z

That seems to be exactly what I want.
I can start this when I the user hits play and it will continue running every few seconds as long as the stream is active? In the callback I can access TrackPlayer?
Do you have some sample code where you run this together with react-native-track-player?
All the other solutions I found, only run once every 15 minutes or so and are used to do background downloads.

curiousdustin · 2019-01-30T15:20:23Z

NOTE: On android if you try to access the player after it has been destroyed, this causes some errors. I haven't worked out all the kinks on my implementation yet, but in general this has been working for me so far.

async function setupPlayer() {
  await TrackPlayer.setupPlayer();

  let playerOptions = { ...options, ...trackPlayerOptions };
  await TrackPlayer.updateOptions(playerOptions);

  startMonitoring();
}

const MONITOR_INTERVAL = 5000;

function startMonitoring() {
  BackgroundTimer.runBackgroundTimer(() => {
    monitorProgress();
  }, MONITOR_INTERVAL);
}

async function monitorProgress() {
  try {
    let playerState = await TrackPlayer.getState();
... do stuff ...
  } catch (error) {
    console.log(error);
  }
}

curiousdustin · 2019-01-30T18:59:11Z

I am still struggling with this actually. If the app is backgrounded for a bit. Android decides to kill the player because it is idle. At this point any code that attempts to run TrackPlayer methods will cause the app to crash with the following error. This includes the setupPlayer() method.

    Process: fm.pinna.app, PID: 19846
    java.lang.IllegalStateException: Not allowed to start service Intent { cmp=fm.pinna.app/com.guichaguri.trackplayer.service.MusicService }: app is in background uid UidRecord{80589ef u0a341 SVC  bg:+1m0s18ms idle procs:1 seq(0,0,0)}
        at android.app.ContextImpl.startServiceCommon(ContextImpl.java:1506)
        at android.app.ContextImpl.startService(ContextImpl.java:1462)
        at android.content.ContextWrapper.startService(ContextWrapper.java:644)
        at android.content.ContextWrapper.startService(ContextWrapper.java:644)
        at com.guichaguri.trackplayer.module.MusicModule.waitForConnection(MusicModule.java:100)
        at com.guichaguri.trackplayer.module.MusicModule.setupPlayer(MusicModule.java:150)
        at java.lang.reflect.Method.invoke(Native Method)
        at com.facebook.react.bridge.JavaMethodWrapper.invoke(JavaMethodWrapper.java:372)
        at com.facebook.react.bridge.JavaModuleWrapper.invoke(JavaModuleWrapper.java:160)
        at com.facebook.react.bridge.queue.NativeRunnable.run(Native Method)
        at android.os.Handler.handleCallback(Handler.java:789)
        at android.os.Handler.dispatchMessage(Handler.java:98)
        at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:29)
        at android.os.Looper.loop(Looper.java:164)
        at com.facebook.react.bridge.queue.MessageQueueThreadImpl$3.run(MessageQueueThreadImpl.java:192)
        at java.lang.Thread.run(Thread.java:764)

curiousdustin · 2019-01-30T19:01:31Z

I should clarify, this is if the player has been setup, but not played anything yet, then the app is backgrounded.

curiousdustin · 2019-01-30T19:05:02Z

I will try getting around this by only running my background code while the player is in its playing state.

Guichaguri · 2019-01-30T21:26:48Z

Yes, the playback service will run as long as the player runs, it's the perfect section to add player-related code that should also run in background. I'm pretty sure react-native-background-timer will create more overhead in this case.

@curiousdustin the issue happens because the app is trying to start a regular service while it's in background. Since Android 8, the app needs to start a foreground service instead of starting a regular one and then foregrounding it.

The problem is that a foreground service requires a notification to be up, and the service only shows a notification after it starts playing.

I can think about two fixes:

Reject any type of call when the player is not in foreground
Start the foreground service as Android expect, but then it's your job to add a track and start playing in less than a second.

The first workaround seems like the proper behavior, as the app should never play anything without an user action in the first place.
The latter one sounds like a racing condition, which is really unstable and will probably end up in spaghetti code.

What do you think?

curiousdustin · 2019-01-30T21:35:13Z

In my case, I determined that I only need to run my background timer while the player is in the playing state. So I start and stop that timer/interval as needed. For now this seems to have avoided all the crashing cases I was running into.

However, now you made me curious.

When you say the "playback service" is the perfect place to add more code, are you saying there is a way to put more functionality into the background task by adding something to the code below?

Is there a way I could create a timer as part of this?

TrackPlayer.registerPlaybackService(() =>
    require('./track-player/TrackPlayerPlaybackService.js')
  );

Right now my TrackPlayerPlaybackService.js file just contains a bunch of calls to TrackPlayer.addEventListener() for all the events. Could I somehow start and stop a timer in there as well? How do you tell when the service is destroyed?

Guichaguri · 2019-01-30T21:44:28Z

You're right, you can run any type of code there. One interesting use-case is for recording analytics data.

There is no event for destroying the service as of yet. Although in you can achieve your goal by registering an interval in playback-track-changed and then unregistering it in playback-queue-ended.

let interval = null;

TrackPlayer.addEventListener('playback-track-changed', () => {
    if (interval == null) interval = setInterval(...);
});

TrackPlayer.addEventListener('playback-queue-ended', () => {
    if (interval != null) {
        clearInterval(interval);
        interval = null;
    }
});

I haven't tested something like this, but it should work.

Guichaguri · 2019-01-30T21:46:25Z

React Native shares the same Javascript context for both the service and the app itself. When the app is closed and the service is destroyed, it should also destroy the context, stopping the timer.

curiousdustin · 2019-01-30T21:53:34Z

Perfect, I will give this a shot and see if I can do it this way instead of using a separate library.

helloagain-dev · 2019-01-31T07:17:26Z

I did try @Guichaguri's proposal, but the setInterval function is not called anymore as soon as I put the App to the background (via Home button).

helloagain-dev · 2019-01-31T07:51:53Z

react-native-background-timer seems to work great.
But I now struggle with updating the Metadata of the notification without stopping the player and queuing the same stream again which would lead to a small pause. Is there any way with the current API to update the artist, title and artwork while the song is playing?

moonstruck · 2019-01-31T09:41:51Z

@helloagain-dev Possibly updating metadata on the fly is not available yet. There's two open pull request in this regard. #384 and #384

ishigamii · 2019-03-05T07:26:16Z

Hi, I am having the same crash on Android very occasionnaly using the version 1.1.2 :

Fatal Exception: java.lang.IllegalStateException: Not allowed to start service Intent { cmp=com.xxx/com.guichaguri.trackplayer.service.MusicService }: app is in background uid UidRecord{39a05c9 u0a454 CEM  bg:+1m5s685ms idle procs:1 seq(0,0,0)}
       at android.app.ContextImpl.startServiceCommon(ContextImpl.java:1538)
       at android.app.ContextImpl.startService(ContextImpl.java:1484)
       at android.content.ContextWrapper.startService(ContextWrapper.java:663)
       at android.content.ContextWrapper.startService(ContextWrapper.java:663)
       at com.guichaguri.trackplayer.module.MusicModule.waitForConnection(MusicModule.java:100)
       at com.guichaguri.trackplayer.module.MusicModule.getPosition(MusicModule.java:405)
       at java.lang.reflect.Method.invoke(Method.java)
       at com.facebook.react.bridge.JavaMethodWrapper.invoke(JavaMethodWrapper.java:372)
       at com.facebook.react.bridge.JavaModuleWrapper.invoke(JavaModuleWrapper.java:160)
       at com.facebook.react.bridge.queue.NativeRunnable.run(NativeRunnable.java)
       at android.os.Handler.handleCallback(Handler.java:789)
       at android.os.Handler.dispatchMessage(Handler.java:98)
       at com.facebook.react.bridge.queue.MessageQueueThreadHandler.dispatchMessage(MessageQueueThreadHandler.java:29)
       at android.os.Looper.loop(Looper.java:164)
       at com.facebook.react.bridge.queue.MessageQueueThreadImpl$3.run(MessageQueueThreadImpl.java:192)
       at java.lang.Thread.run(Thread.java:764)

xgustavoh · 2019-04-23T00:07:24Z

@helloagain-dev, Look #552

curiousdustin · 2020-04-26T23:50:34Z

Closing this as the original question has been answered.

Also metadata update is part of v2.
See #634

Guichaguri added the Platform: Android label Jan 30, 2019

curiousdustin closed this as completed Apr 26, 2020

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Running code while streaming in background #419

Running code while streaming in background #419

helloagain-dev commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

helloagain-dev commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

Guichaguri commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

Guichaguri commented Jan 30, 2019

Guichaguri commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

helloagain-dev commented Jan 31, 2019

helloagain-dev commented Jan 31, 2019

moonstruck commented Jan 31, 2019

ishigamii commented Mar 5, 2019 •

edited

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xgustavoh commented Apr 23, 2019

curiousdustin commented Apr 26, 2020

Running code while streaming in background #419

Running code while streaming in background #419

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helloagain-dev commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

helloagain-dev commented Jan 30, 2019

curiousdustin commented Jan 30, 2019

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helloagain-dev commented Jan 31, 2019

helloagain-dev commented Jan 31, 2019

moonstruck commented Jan 31, 2019

ishigamii commented Mar 5, 2019 • edited Loading

xgustavoh commented Apr 23, 2019

curiousdustin commented Apr 26, 2020

ishigamii commented Mar 5, 2019 •

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