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react-native-background-job

react-native-background-job npm version CircleCI

Schedule background jobs that run your JavaScript when your app is in the background or if you feel brave even in foreground.

The jobs will run even if the app has been closed and, by default, also persists over restarts.

This library relies on React Native's HeadlessJS which is currently only supported on Android.

On the native side it uses either Firebase JobDispatcher or a AlarmManager.

  • Firebase JobDispatcher (default): The jobs can't be scheduled exactly and depending on the Android API version different period time is allowed. FirebaseJobDispatcher is the most battery efficient backward compatible way of scheduling background tasks.

  • AlarmManager by setting exact to true: Simple propriatery implementation that is only ment to be used while testing. It only cares about executing on time, all other parameters are ignored - job is not persisted on reboot.

Requirements

  • RN 0.36+
  • Android API 16+

Supported platforms

  • Android

Want iOS? Go in and vote for Headless JS to be implemented for iOS: Product pains

Getting started

$ yarn add react-native-background-job

or

$ npm install react-native-background-job --save

Mostly automatic installation

$ react-native link react-native-background-job

Manual installation

Android

  1. Open up android/app/src/main/java/[...]/MainActivity.java

    • Add import com.pilloxa.backgroundjob.BackgroundJobPackage; to the imports at the top of the file
    • Add new BackgroundJobPackage() to the list returned by the getPackages() method in MainApplication.java
  2. Append the following lines to android/settings.gradle:

        include ':react-native-background-job'
        project(':react-native-background-job').projectDir = new File(rootProject.projectDir, 	'../node_modules/react-native-background-job/android')
    
  3. Insert the following lines inside the dependencies block in android/app/build.gradle and bump the minSdkVersion to 21:

          compile project(':react-native-background-job')
    

Usage

The jobs have to be registered each time React Native starts, this is done using the register function. Since HeadlessJS does not mount any components the register function must be run outside of any class definitions (see example/index.android.js)

Registering the job does not mean that the job is scheduled, it just informs React Native that this job function should be tied to this jobKey. The job is then scheduled using the schedule function. By default, the job will not fire while the app is in the foreground. This is since the job is run on the only JavaScript thread and if running the job when app is in the foreground it would freeze the app. By setting allowExecutionInForeground to true you allow this behavior. It is recommended that you do't use this, but for quick jobs should be fine.

For a full example check out example/index.android.js

API

register

Registers the job and the functions they should run.

This has to run on each initialization of React Native and it has to run in the global scope and not inside any component life cycle methods. See example project. Only registering the job will not schedule the job. It has to be scheduled by schedule to start running.

Parameters

  • obj Object
    • obj.jobKey string A unique key for the job
    • obj.job function The JS-function that will be run

Examples

import BackgroundJob from 'react-native-background-job';
 
const backgroundJob = {
 jobKey: "myJob",
 job: () => console.log("Running in background")
};
 
BackgroundJob.register(backgroundJob);

schedule

Schedules a new job.

This only has to be run once while register has to be run on each initialization of React Native.

Parameters

  • obj Object
    • obj.jobKey string A unique key for the job that was used for registering, and be used for canceling in later stage.
    • obj.timeout number The amount of time (in ms) after which the React instance should be terminated regardless of whether the task has completed or not. (optional, default 2000)
    • obj.period number The frequency to run the job with (in ms). This number is not exact, Android may modify it to save batteries. Note: For Android > N, the minimum is 900 0000 (15 min). (optional, default 900000)
    • obj.persist boolean If the job should persist over a device restart. (optional, default true)
    • obj.override boolean Whether this Job should replace pre-existing jobs with the same key. (optional, default true)
    • obj.networkType number Only run for specific network requirements. (optional, default NETWORK_TYPE_NONE)
    • obj.requiresCharging boolean Only run job when device is charging, (not respected by pre Android N devices) docs (optional, default false)
    • obj.requiresDeviceIdle boolean Only run job when the device is idle, (not respected by pre Android N devices) docs (optional, default false)
    • obj.exact boolean Schedule an job to be triggered precisely at the provided period. Note that this is not power-efficient way of doing things. (optional, default false)
    • obj.allowExecutionInForeground boolean Allow the scheduled job to be executed even when the app is in foreground. Use it only for short running jobs. (optional, default false)

Examples

import BackgroundJob from 'react-native-background-job';
 
const backgroundJob = {
 jobKey: "myJob",
 job: () => console.log("Running in background")
};
 
BackgroundJob.register(backgroundJob);
 
var backgroundSchedule = {
 jobKey: "myJob",
}
 
BackgroundJob.schedule(backgroundSchedule);

cancel

Cancel a specific job

Parameters

Examples

import BackgroundJob from 'react-native-background-job';
 
BackgroundJob.cancel({jobKey: 'myJob'});

cancelAll

Cancels all the scheduled jobs

Examples

import BackgroundJob from 'react-native-background-job';
 
BackgroundJob.cancelAll();

setGlobalWarnings

Sets the global warning level

Parameters

Examples

import BackgroundJob from 'react-native-background-job';
 
BackgroundJob.setGlobalWarnings(false);

Debugging

If you are using Android API +25 you can manually trigger the jobs by using the following command in a terminal:

$ adb shell cmd jobscheduler run -f your.package jobIntId

jobIntId: is the hashed jobKey. Get that value by going to Java REPL and input:

"yourJobKey".hashCode();
// 1298333557 

Troubleshooting

No task registered for key myJob

Make sure you call the register function at the global scope (i.e. not in any component life cycle methods (render, iDidMount etc)). Since the components are not rendered in Headless mode if you run the register function there it will not run in the background and hence the library will not find which function to run.

See example project

AppState.currentState is "active" when I'm running my Headless task in the background

This is a React Native issue, you can get around it by calling NativeModules.AppState.getCurrentAppState directly instead.

My job always runs in the background even if I specified requiresCharging, requiresDeviceIdle or a specific networkType

This is an Android issue, it seems that you can not have these restrictions at the same time as you have a periodic interval for pre Android N devices.

Sponsored by

pilloxa