Web Push

The Web Push transport sends to browsers with the Web Push protocol: VAPID authentication and RFC 8291 payload encryption. It ships in the Shiny.Extensions.Push package (namespace Shiny.Extensions.Push.WebPush) and delivers to registrations with Platform = DevicePlatform.WebBrowser. Web Push has no multicast endpoint, so each device is one request, sent concurrently.

VAPID keys

There’s no store console. Generate a key pair once, for example with the web-push CLI:

npx web-push generate-vapid-keys

Both keys are base64url. Any P-256 pair works: the public key is the 65-byte uncompressed point and the private key the 32-byte scalar. The public key goes in the app and the private key stays on the server. If you change the pair, every existing subscription stops working and browsers have to subscribe again.

The app side (the WebPushOptions.VapidPublicKey and the service worker) is covered in the client Platform Setup → Web Push.

Configuration

using Shiny.Extensions.Push.WebPush;

push.AddWebPush(o =>
{
    o.PublicKey  = "<vapid-public-key>";
    o.PrivateKey = "<vapid-private-key>";
    o.Subject    = "mailto:you@example.com";
});

Option	Description
PublicKey	VAPID public key (base64url)
PrivateKey	VAPID private key (base64url)
Subject	A mailto: or https: contact the push service can use to reach you
DefaultTimeToLive	How long the push service keeps an undelivered message. Defaults to 28 days.

Registering devices

A browser subscription has three parts. The endpoint goes in DeviceToken and the two keys go in Data under p256dh and auth. A registration without both keys fails with InvalidToken. See Client Apps → Web Push for parsing the JSON Shiny.Push reports.

await pushManager.RegisterDevice(new DeviceRegistration
{
    DeviceToken = subscription.Endpoint,
    Platform    = DevicePlatform.WebBrowser,
    Data        = new Dictionary<string, string>
    {
        ["p256dh"] = subscription.P256dh,
        ["auth"]   = subscription.Auth
    }
});

Payload

The encrypted payload is JSON with title, body, icon (from WebPushOptions.Icon), deeplink and data. The Shiny.Push service worker shows title, body and icon and passes data to IPushDelegate, so put anything the app needs, including deep links, in Data.

Failure handling

Push service response	Status	Manager action
404 / 410	TokenExpired	subscription pruned
missing keys, bad endpoint, encryption error	InvalidToken	subscription pruned
429 / 503	RateLimited	surfaced (no auto-retry)