NativeScript を使用したリアルタイム アプリケーションの開発: プッシュ通知の実装

const functions = require('firebase-functions'); // for listening to http triggers
const admin = require('firebase-admin'); // for accessing the realtime database
admin.initializeApp(functions.config().firebase); // initialize the Firebase Admin SDK

exports.init_push = functions.https.onRequest((request, response) => {
    
    if(request.method == 'POST'){

        var id = request.body.id; // ID of the user who made the request (Firebase Auth ID)
        var steps = parseInt(request.body.steps); // latest steps, not recorded yet
        var friend_ids = request.body.friend_ids.split(','); 

        friend_ids.push(id); // also include the ID of the current user

        // next: add code for getting the user and friends data
    }

});

admin.database().ref('/users')
    .orderByChild('id')
    .limitToFirst(1)
    .equalTo(id)
    .once('value').then(snapshot => {
    
    var user_data = snapshot.val();

    if(user_data){
        // get all users from the database
        admin.database().ref('/users')
            .once('value').then(snapshot => {
            // next: add code for getting the current user's data and their friends data
        });
    }
});

var friends_data = [];
var current_user_data = null;
var notification_data = {};
var has_notification = false;

var users = snapshot.val();
for(var key in users){
    var user_id = users[key].id;
    
    if(friend_ids.indexOf(user_id) != -1 && id != user_id){ // the current user's friends
        friends_data.push(users[key]);
    }else if(id == user_id){ // the current user
        current_user_data = users[key];
    }
}

// sort in descending order by the number of steps
var sorted_friends_data = friends_data.sort(function(a, b) {
    return b.steps - a.steps;
}); 

// next: add code for constructing the notification payload

if(steps > sorted_friends_data[0].steps){
    // notify friend who was overtaken
    var diff_steps = steps - sorted_friends_data[0].steps;
    notification_data = {
        payload: {
            title: 'One of your friends beat your record',
            body: 'Too bad, your friend ' + current_user_data.user_name + ' just overtook you by ' + diff_steps + ' steps'
        },
        device_token: sorted_friends_data[0].device_token
    };
    has_notification = true;
    
}else if(steps > current_user_data.steps){
    // notify current user
    var diff_steps = steps - current_user_data.steps;
    notification_data = {
        payload: {
            title: 'You beat your record!',
            body: 'Congrats! You beat your current record by ' + diff_steps + ' steps!' 
        },
        device_token: current_user_data.device_token
    };
    has_notification = true;
}

// next: add code for sending push notification

if(has_notification){
    
    var payload = {
      notification: notification_data.payload
    };
    
    // send push notification
    admin.messaging().sendToDevice(notification_data.device_token, payload).then(function(res) {
        
        response.send(JSON.stringify({'has_notification': true})); // inform the app that a notification was sent
    })
    .catch(function(error) {
        response.send(JSON.stringify(error)); // send the push notification error to the app
    });

}else{
    response.send(JSON.stringify({'has_notification': false})); // inform the app that a notification was not sent
}

onPushTokenReceivedCallback: function(token) {
    // temporarily save it to application settings until such time that 
    // the user logs in for the first time
    applicationSettings.setString('device_token', token);
},

onMessageReceivedCallback: function(message) {
    dialogs.alert({
        title: message.title,
        message: message.body,
        okButtonText: "ok"
    });
},

if(firebase_result.value == null){ 

    var device_token = applicationSettings.getString('device_token');

    var user_data = {
        'uid': fb_result.uid,
        'user_name': fb_result.name,
        'profile_photo': fb_result.profileImageURL,
        'device_token': device_token 
    };

}

// extracting the friend IDs from the Facebook result
var friends_ids = r.data.map(function(obj){
    return obj.id;
});

// save the friend IDs
applicationSettings.setString('friends_ids', JSON.stringify(friends_ids));

friends_ids.push(user[user_key].id);

// construct the user data for updating the user's distance and steps
var user_key = applicationSettings.getString('user_key');
var user = applicationSettings.getString('user');
var user_data = JSON.parse(user);
user_data[user_key].distance = total_distance;
user_data[user_key].steps = total_steps;

// get friend IDs
var friends_ids = JSON.parse(applicationSettings.getString('friends_ids'));

var request_data = {
    'id': user_data[user_key].id,
    'friend_ids': friends_ids.join(','),
    'steps': total_steps
};

http.request({ 
    url: "https://us-central1-pushapp-ab621.cloudfunctions.net/init_push", 
    method: "POST",
    headers: { "Content-Type": "application/json" },
    content: JSON.stringify(request_data) 
}).then(function (response) {
   
    var statusCode = response.statusCode;
    if(statusCode == 200){
        // update the user's data on Firebase
        firebase.update(
            '/users',
            user_data
        ); 

    }

}, function (e) {
    console.log('Error occurred while initiating push: ', e);
});

onPushTokenReceivedCallback: function(token) {
    applicationSettings.setString('device_token', token);
    console.log('device token: ', device_token); // <-- add this
}

curl -X POST -H "Content-Type:application/json" YOUR_FIREBASE_FUNCTION_ENDPOINT -d '{"id":"ID OF A FIREBASE USER", "steps":NUMBER_OF_STEPS, "friend_ids":"COMMA,SEPARATED,FIREBASE,USER_IDs"}'

{"id":"ID OF A FIREBASE USER", "steps":NUMBER_OF_STEPS, "friend_ids":"COMMA,SEPARATED,FIREBASE,USER_IDs"}