Expo integration of the android UnifiedPush library.
This library is only supported on Android at the moment. For iOS suport, we recommend using the RN Push Notifications library or the Expo Notifications library.
Main documentation is available at ExpoUnifiedPushModule typedoc pages.
For managed Expo projects, please follow the installation instructions in the API documentation.
For bare React Native projects, you must ensure that you have installed and configured the expo package before continuing.
npm install expo-unified-push
To see an example implementation of the library, you can check the App.tsx file in the example folder.
By default, this module expects the decrypted push payload sent from the backned to be a JSON string shaped like this:
{ "id": 123, "title": "...", "body": "...", "url": "..." }
... and some other properties not included here.
It uses this shape to build a native android notification and present it without touching the JS/React side of things, so it works even if the system has killed or backgrounded your app.
But there are cases where you cannot exactly control the shape of data coming from your backend. In these cases, you can implement a custom PushPayloadRenderer to format your data and register it via the payloadRendererClass config plugin option like this:
// app.config.js
{
plugins: [
['expo-unified-push', { payloadRendererClass: 'com.example.app.push.MyPushPayloadRenderer' }],
],
}
This is an example of what a custom PushPayloadRenderer can look like:
// android/app/src/main/java/com/example/app/push/MyPushPayloadRenderer.kt
package com.example.app.push
import android.content.Context
import dev.djara.expounifiedpush.NotificationContent
import dev.djara.expounifiedpush.PushPayloadRenderer
class MyPushPayloadRenderer : PushPayloadRenderer {
override fun render(context: Context, instance: String, decrypted: String): NotificationContent? {
// parse `decrypted` however your payload is shaped, or return null to show nothing
return NotificationContent(id = 1, title = "...", body = decrypted)
}
}
The class needs a public no-arg constructor and must be compiled into your app. Since managed/CNG Expo projects can't hand-edit android/, you can put it in a local Expo module (e.g. under ./modules) rather than directly under android/app/, so it survives a expo prebuild --clean.
The render method of your custom PushPayloadRenderer is called from a small android service (ExpoUPService.kt) and has no connection to the JS or React side so it must not depend on the RN bridge and should be fast and synchronous.
To send notifications from your backend, use the web-push npm library or something similar. It will handle all encoding of parameters for you. Remember to set up VAPID keys for improved security (more info on the web-push readme)
Contributions are very welcome! Just make sure to keep the code style consistent with the rest of the codebase and ask before adding any new dependencies.