Module push_service 

Web Push notification service.

Stores push subscriptions per wallet in Postgres and delivers notifications via the Web Push protocol (VAPID-signed, RFC 8291).

Subscriptions are cached in memory (DashMap) to avoid a DB query on every fill. The cache is invalidated on subscribe/unsubscribe.

Push delivery is decoupled from the event forwarder via a bounded mpsc channel. A single background task drains the queue and sends up to MAX_CONCURRENT_SENDS push messages in parallel.

Structs

PushJob 🔒

Internal message sent through the bounded channel from the event forwarder to the background push sender task.

PushNotificationService

PushPayload

JSON payload sent inside the push message. The service worker parses this to decide what to show.

Enums

NotificationType

Notification category. The backend checks the user’s preferences before sending a push for each category.

Constants

ALLOWED_PUSH_ENDPOINT_PREFIXES 🔒

Allowed push endpoint URL prefixes. Rejects anything that isn’t a known browser push service to prevent SSRF.

CACHE_MAX_ENTRIES 🔒

Maximum number of wallets to cache. When exceeded, the cache is cleared entirely (simple eviction strategy suitable for this use case since most entries are empty vecs and re-population is cheap).

MAX_CONCURRENT_SENDS 🔒

Maximum number of push HTTP requests in flight at once.

MAX_SUBSCRIPTIONS_PER_WALLET 🔒

Maximum push subscriptions per wallet. Prevents a single wallet from registering thousands of endpoints.

PUSH_QUEUE_CAPACITY 🔒

Bounded channel capacity for pending push jobs. If the sender task falls behind, new jobs are dropped (best-effort delivery).

Functions

default_preferences

Default preferences: everything enabled.

get_subscriptions 🔒

Load subscriptions for a wallet, using cache when available.

is_enabled 🔒

Check whether a subscription has a given notification type enabled. Missing keys default to enabled. Non-boolean values are treated as disabled (reject malformed preferences rather than silently enabling).

push_sender_loop 🔒

Single background task that drains the push job queue and sends notifications with bounded concurrency.

remove_stale 🔒

to_base64url 🔒

Normalize a base64 or base64url string to base64url (no padding).