I am new to service workers and GAE, I am able to register the service workers but not able to subscribe the PushManager, getting subscription null error. Find the below code for reference.
serviceWorkerRegistration.pushManager.getSubscription()
.then(function(subscription) {
var pushButton = document.querySelector('.js-push-button');
pushButton.disabled = false;
if (!subscription) {
console.log('subscription error ');
return;
}
console.log('subscriptioned ');
// Keep your server in sync with the latest subscriptionId
sendSubscriptionToServer(subscription);
// Set your UI to show they have subscribed for
// push messages
pushButton.textContent = 'Disable Push Messages';
isPushEnabled = true;
})
.catch(function(err) {
console.warn('Error during getSubscription()', err);
});
});
In above code getting "subscription" value as "null" inside then, so that, control is coming to if block and simply returning.
Initially, when the user isn't subscribed, the promise returned by
getSubscription
resolves tonull
. You need to callregistration.pushManager.subscribe
in order to subscribe the user (and then, the next time the user visits your site,getSubscription
will resolve with a non-null subscription).There are many examples on the ServiceWorker Cookbook.
A simple example here: