# Firebase Cloud Messaging for Flutter

[![pub package](https://img.shields.io/pub/v/firebase_messaging.svg)](https://pub.dartlang.org/packages/firebase_messaging)

A Flutter plugin to use the [Firebase Cloud Messaging (FCM) API](https://firebase.google.com/docs/cloud-messaging/).

With this plugin, your Flutter app can receive and process push notifications as well as data messages on Android and iOS. Read Firebase's [About FCM Messages](https://firebase.google.com/docs/cloud-messaging/concept-options) to learn more about the differences between notification messages and data messages.

For Flutter plugins for other Firebase products, see [FlutterFire.md](https://github.com/flutter/plugins/blob/master/FlutterFire.md).

*Note*: This plugin is still under development, and some APIs might not be available yet. [Feedback](https://github.com/flutter/flutter/issues) and [Pull Requests](https://github.com/flutter/plugins/pulls) are most welcome!

## Usage
To use this plugin, add `firebase_messaging` as a [dependency in your pubspec.yaml file](https://flutter.io/platform-plugins/).

## Getting Started

Check out the `example` directory for a sample app using Firebase Cloud Messaging.

### Android Integration

To integrate your plugin into the Android part of your app, follow these steps:

1. Using the [Firebase Console](https://console.firebase.google.com/) add an Android app to your project: Follow the assistant, download the generated `google-services.json` file and place it inside `android/app`. Next, modify the `android/build.gradle` file and the `android/app/build.gradle` file to add the Google services plugin as described by the Firebase assistant.

1. (optional, but recommended) If want to be notified in your app (via `onResume` and `onLaunch`, see below) when the user clicks on a notification in the system tray include the following `intent-filter` within the `<activity>` tag of your `android/app/src/main/AndroidManifest.xml`:
  ```xml
  <intent-filter>
      <action android:name="FLUTTER_NOTIFICATION_CLICK" />
      <category android:name="android.intent.category.DEFAULT" />
  </intent-filter>
  ```

### iOS Integration

To integrate your plugin into the iOS part of your app, follow these steps:

1. Generate the certificates required by Apple for receiving push notifications following [this guide](https://firebase.google.com/docs/cloud-messaging/ios/certs) in the Firebase docs. You can skip the section titled "Create the Provisioning Profile".

1. Using the [Firebase Console](https://console.firebase.google.com/) add an iOS app to your project: Follow the assistant, download the generated `GoogleService-Info.plist` file, open `ios/Runner.xcworkspace` with Xcode, and within Xcode place the file inside `ios/Runner`. **Don't** follow the steps named "Add Firebase SDK" and "Add initialization code" in the Firebase assistant.

1. In Xcode, select `Runner` in the Project Navigator. In the Capabilities Tab turn on `Push Notifications`.

1. Remove the `use_frameworks!` line from `ios/Podfile` (workaround for [flutter/flutter#9694](https://github.com/flutter/flutter/issues/9694)).

1. Follow the steps in the "[Upload your APNs certificate](https://firebase.google.com/docs/cloud-messaging/ios/client#upload_your_apns_certificate)" section of the Firebase docs.

### Dart/Flutter Integration

From your Dart code, you need to import the plugin and instantiate it:

```dart
import 'package:firebase_messaging/firebase_messaging.dart';

final FirebaseMessaging _firebaseMessaging = FirebaseMessaging();
```

Next, you should probably request permissions for receiving Push Notifications. For this, call `_firebaseMessaging.requestNotificationPermissions()`. This will bring up a permissions dialog for the user to confirm on iOS. It's a no-op on Android. Last, but not least, register `onMessage`, `onResume`, and `onLaunch` callbacks via `_firebaseMessaging.configure()` to listen for incoming messages (see table below for more information).

## Receiving Messages

Messages are sent to your Flutter app via the `onMessage`, `onLaunch`, and `onResume` callbacks that you configured with the plugin during setup. Here is how different message types are delivered on the supported platforms:

|                             | App in Foreground | App in Background | App Terminated |
| --------------------------: | ----------------- | ----------------- | -------------- |
| **Notification on Android** | `onMessage` | Notification is delivered to system tray. When the user clicks on it to open app `onResume` fires if `click_action: FLUTTER_NOTIFICATION_CLICK` is set (see below). | Notification is delivered to system tray. When the user clicks on it to open app `onLaunch` fires if `click_action: FLUTTER_NOTIFICATION_CLICK` is set (see below). |
| **Notification on iOS** | `onMessage` | Notification is delivered to system tray. When the user clicks on it to open app `onResume` fires. | Notification is delivered to system tray. When the user clicks on it to open app `onLaunch` fires. |
| **Data Message on Android** | `onMessage` | `onMessage` while app stays in the background. | *not supported by plugin, message is lost* |
| **Data Message on iOS**     | `onMessage` | Message is stored by FCM and delivered to app via `onMessage` when the app is brought back to foreground. | Message is stored by FCM and delivered to app via `onMessage` when the app is brought back to foreground. |

Additional reading: Firebase's [About FCM Messages](https://firebase.google.com/docs/cloud-messaging/concept-options).

## Sending Messages
Refer to the [Firebase documentation](https://firebase.google.com/docs/cloud-messaging/) about FCM for all the details about sending messages to your app. When sending a notification message to an Android device, you need to make sure to set the `click_action` property of the message to `FLUTTER_NOTIFICATION_CLICK`. Otherwise the plugin will be unable to deliver the notification to your app when the users clicks on it in the system tray.

For testing purposes, the simplest way to send a notification is via the [Firebase Console](https://firebase.google.com/docs/cloud-messaging/send-with-console). Make sure to include `click_action: FLUTTER_NOTIFICATION_CLICK` as a "Custom data" key-value-pair (under "Advanced options") when targeting an Android device. The Firebase Console does not support sending data messages.

Alternatively, a notification or data message can be sent from a terminal:

```shell
DATA='{"notification": {"body": "this is a body","title": "this is a title"}, "priority": "high", "data": {"click_action": "FLUTTER_NOTIFICATION_CLICK", "id": "1", "status": "done"}, "to": "<FCM TOKEN>"}'
curl https://fcm.googleapis.com/fcm/send -H "Content-Type:application/json" -X POST -d "$DATA" -H "Authorization: key=<FCM SERVER KEY>"
```

Remove the `notification` property in `DATA` to send a data message.