service-worker.js

var OFFLINE_CACHE = 'offline';
var OFFLINE_URL = 'html/offline.html';

self.addEventListener('install', function (event) {
    var offlineRequest = new Request(OFFLINE_URL);
    event.waitUntil(
        fetch(offlineRequest).then(function (response) {
            return caches.open(OFFLINE_CACHE).then(function (cache) {
                return cache.put(offlineRequest, response);
            });
        })
    );
});

self.addEventListener('fetch', function (event) {
    if (event.request.mode === 'navigate' ||
        (event.request.method === 'GET' &&
        event.request.headers.get('accept').includes('text/html'))) {

        // a GET request should not have any body (blob), but sometimes it does
        event.waitUntil(event.request.blob().then(function(blob) {
            if (blob.size == 0) {
                return event.respondWith(
                    fetch(event.request).catch(function () {
                        // offline
                        return caches.open(OFFLINE_CACHE).then(function (cache) {
                            return cache.match(OFFLINE_URL);
                        });
                    })
                );
            }
        }));
    }
});

self.addEventListener('push', function (event) {
    if (!(self.Notification && self.Notification.permission === 'granted')) {
        return;
    }

    var sendNotification = function(message, tag) {
        // on actualise la page des notifications ou/et le compteur de notifications
        self.refreshNotifications();

        var title = "Phy'sbook",
            icon = 'images/icons/icon-192.png';

        message = message || 'Il y a du neuf !';
        tag = tag || 'general';

        return self.registration.showNotification(title, {
            body: message,
            icon: icon,
            tag: tag
        });
    };

    if (event.data) {
        var data = event.data.json();
        event.waitUntil(
            sendNotification(data.message, data.tag)
        );
    } else {
        event.waitUntil(
            self.registration.pushManager.getSubscription().then(function(subscription) {
                if (!subscription) {
                    return;
                }

                return fetch('api/notifications/last?endpoint=' + encodeURIComponent(subscription.endpoint)).then(function (response) {
                    if (response.status !== 200) {
                        throw new Error();
                    }

                    // Examine the text in the response
                    return response.json().then(function (data) {
                        if (data.error || !data.notification) {
                            throw new Error();
                        }

                        return sendNotification(data.notification.message);
                    });
                }).catch(function () {
                    return sendNotification();
                });
            })
        );
    }
});

self.refreshNotifications = function(clientList) {
    if (clientList == undefined) {
        clients.matchAll({ type: "window" }).then(function (clientList) {
            self.refreshNotifications(clientList);
        });
    } else {
        for (var i = 0; i < clientList.length; i++) {
            var client = clientList[i];
            if (client.url.search(/notifications/i) >= 0) {
                // si la page des notifications est ouverte on la recharge
                client.postMessage('reload');
            }

            // si on n'est pas sur la page des notifications on recharge le compteur
            client.postMessage('refreshNotifications');
        }
    }
};

self.addEventListener('notificationclick', function (event) {
    // fix http://crbug.com/463146
    event.notification.close();

    event.waitUntil(
        clients.matchAll({
            type: "window"
        })
            .then(function (clientList) {
                // si la page des notifications est ouverte on l'affiche en priorité
                for (var i = 0; i < clientList.length; i++) {
                    var client = clientList[i];
                    if (client.url.search(/notifications/i) >= 0 && 'focus' in client) {
                        return client.focus();
                    }
                }

                // sinon s'il y a quand même une page du site ouverte on l'affiche
                if (clientList.length && 'focus' in client) {
                    return client.focus();
                }

                // sinon on ouvre la page des notifications
                if (clients.openWindow) {
                    return clients.openWindow('notifications');
                }
            })
    );
});

self.addEventListener('message', function (event) {
    var message = event.data;

    switch (message) {
        case 'dispatchRemoveNotifications':
            clients.matchAll({ type: "window" }).then(function (clientList) {
                for (var i = 0; i < clientList.length; i++) {
                    clientList[i].postMessage('removeNotifications');
                }
            });
            break;
        default:
            console.warn("Message '" + message + "' not handled.");
            break;
    }
});