A notification can arrive from someone whose profile the main app has
never loaded. The iOS notification extension now fetches and caches
sender profiles, channel details, and avatars itself. The main app
supplies account configuration and Keychain credentials only.
After resolving the message, the extension allows 1.5 seconds for sender
and channel details. It uses available stale data when a refresh is slow
or fails, delivers once, and lets late results update its private cache.
Profiles, channel details, and avatar refresh checks share a one-hour
freshness threshold. A verified avatar removal clears the previous
image. Account removal prevents further use of that sign-in's cached
data.
Profile, channel metadata, and membership use separate bounded
downloads, so an oversized roster cannot discard the smaller records.
Sender enrichment can finish while channel requests are pending. A
successful partial channel refresh atomically removes its old
counterpart, preventing a mixed group identity or recipient count.
Group-specific notification presentation still requires a verified
recipient count.
The
[specification](https://github.com/block/buzz/blob/native-notification-enrichment/docs/native-notification-enrichment.md)
describes the display, caching, and account-removal behavior. General
persistent image caching in Flutter remains separate.
### Validation
[Hosted CI](https://github.com/block/buzz/actions/runs/38780108487)
passed on the final commit, including all Flutter shards, Android, the
full iOS release and simulator builds, and native
controls/push-navigation tests. The [current-commit security
review](https://github.com/block/buzz/pull/8369#issuecomment-6197508385)
found no issues.
The native package passed 159 tests, including new coverage for cache
freshness, avatar replacement and removal, sign-in isolation, concurrent
storage, late results, single delivery, bounded downloads, and SVG
validation. A regression test exposed identical HTTP authentication
event IDs for requests in the same second; each request now includes a
unique nonce, matching the Dart and CLI clients.
Full local CI passed before that small authentication fix. The complete
native suite and signed device build passed again on the latest commit,
including response-size limits, overlapping avatar downloads, canonical
relay-origin matching, independent profile/channel refreshes,
account-key changes before and during requests, and a single initial
snapshot read across 64 accounts, signed IPv6 avatar authorities, and
partial channel refreshes. Focused Flutter regression tests passed 198
tests with three configuration-specific skips; seven avatar widget tests
also passed. Flutter analysis is clean, and the notification extension
builds for the simulator.
On an iPhone SE, the notification displayed the sender name, avatar,
channel, and message before the updated main app was opened. Repeat
notifications used a byte-identical private cache. Three notifications
delivered together displayed the avatar after the authentication fix.
The next notification also displayed correctly after terminating the
extension process. The existing generic-push design can select the same
newest unread message for several pushes; this change does not alter
message selection.
Authenticated HTTP avatar fetching and persistent HTTP cache reuse also
passed on the SE. The first notification downloaded a relay thumbnail.
After terminating the extension and expiring its separate avatar entry,
the next notification displayed the avatar and refreshed that entry
without another media request in the relay logs. The main app remained
unopened throughout. The original app build and test profile were
restored afterward.
Automated tests cover slow and failed requests, stale images, removal,
and account revocation; those cases have not all been exercised on the
phone.
### Before merge
- [x] Verify authenticated HTTP avatar fetching and cache reuse on iOS
against a working relay media service.
<!-- buzz-review-completed -->
---------
Signed-off-by: Tom Brow <tomb@block.xyz>
This PR implements MVP, iOS-only,
[NIP-PL](8d2d0ff5ad/docs/nips/NIP-PL.md)-compliant
push notifications.
A relay with `BUZZ_PUSH_ENABLED` will send a push notification for any
message that appears in the in-app Notifications tab.
## Enrollment flow
The first time the client first connects to a relay with
`BUZZ_PUSH_ENABLED`:
```mermaid
sequenceDiagram
autonumber
participant App as Buzz iOS app
participant iOS
participant Relay as Buzz relay
participant Attest as Apple App Attest
participant Gateway as Push gateway
App->>Relay: Fetch NIP-11 push capability
Relay-->>App: Push profile, current relay public key, and limits
par
App->>iOS: Request notification permission
iOS-->>App: Permission result
and
App->>iOS: Register for remote notifications
iOS-->>App: Device token
end
App->>Gateway: Request installation challenge
Gateway-->>App: Single-use challenge
App->>Attest: Attest installation transcript
Attest-->>App: Attestation proof
App->>Gateway: Enroll device token and proof
Gateway-->>App: Installation handle
App->>Gateway: Request delegation challenge
Gateway-->>App: Single-use challenge
App->>Attest: Assert relay-key delegation
Attest-->>App: Assertion
App->>Gateway: Create delegation
Gateway-->>App: Opaque endpoint grant
App->>Relay: Publish encrypted push lease and filters
Relay-->>App: Lease acknowledged
```
## Push-time flow
When a notification-eligible event is received by the relay:
```mermaid
%%{init: {
"sequence": {
"actorMargin": 20,
"width": 110,
"messageMargin": 18,
"diagramMarginX": 8,
"wrap": true
}
}}%%
sequenceDiagram
autonumber
participant Relay as Buzz relay
participant Gateway as Push gateway
participant APNs as Apple Push<br/>Notification service
participant iOS
participant NSE as Notification service<br/>extension
Relay->>Gateway: POST /v1/deliveries/apns<br/>opaque endpoint grant, request ID, expiry, NIP-98 authorization
Gateway->>APNs: POST /3/device/{device-token}<br/>topic, request ID, expiry, constant mutable-content payload
APNs-->>Gateway: 200 OK: request accepted
Gateway-->>Relay: 200 OK: accepted status
APNs-->>iOS: Notification: constant reconnect alert<br/>mutable-content = 1
iOS->>NSE: Invoke extension<br/>original notification content
NSE->>Relay: POST /query: subscription filters, limit 10<br/>NIP-98 authorization
Relay-->>NSE: 200 OK: signed Nostr events<br/>kinds 9, 40002, 45001, or 45003
NSE->>iOS: Complete notification: title, body, subtitle<br/>thread ID, exact-message target
```
relay → push gateway → APNs -> NSE -> Notification Center
## Known limitations
The APNs wake payload is intentionally constant and opaque: it contains
no originating community or message identifier, in keeping with the
implemented NIP-PL privacy design.
The Notification Service Extension must therefore reconnect to the relay
and resolve eligible messages after each wake. Around overlapping wakes,
timing boundaries, or resolution windows, notification presentation may
occasionally omit an expected message or display a message more than
once.
This best-effort behavior is deliberately accepted for the current
implementation and will be measured during the internal rollout to
determine whether the user experience is acceptable before any broader
deployment; the implementation does not claim exactly-once presentation.
## Validation
Live end-to-end hardware validation used an internal remotely hosted
development relay and push gateway, the APNs sandbox, and a physical
iPhone 12 mini:
- A second real Buzz client published a uniquely marked message through
the hosted relay.
- The relay matched the message and sent the constant opaque wake
through the hosted gateway. The gateway made an actual APNs request; no
`simctl push` or simulated notification was used.
- The iPhone received the notification on its lock screen. The
Notification Service Extension reconnected to the relay, fetched the
event, verified its ID and signature, and replaced the placeholder
content with the real notification title and body.
- After the app populated its shared presentation cache, a final marked
notification visibly showed the sender display name, sender avatar, and
hashtag-prefixed channel name.
- Tapping a lock-screen notification opened Buzz and exercised the
notification-response path and navigated to the corresponding message.
Final validation with a dogfood-signed artifact and production App
Attest/APNs configuration remains a release step.
## Independent pre-reviews
- **First pass:**
[Carl](buzz://message?channel=18882f4c-289f-41db-942f-81f6f8066da1&id=74ab9a93bb227f3e762568f1cf9fee66d7495b0edc3918735ff787238b9cc585)
found missing transient retries, executor-key rotation suppression,
duplicate installation renewal, and an unauthenticated challenge write
amplifier. These were resolved by [retry-safe
bootstrap](https://github.com/block/buzz/pull/6269/changes/12c66ea62)
and [authenticated renewal plus a cross-replica
quota](https://github.com/block/buzz/pull/6269/changes/8e5ece0bd).
[sol-max](buzz://message?channel=ad83385f-8e9e-4461-9a35-c1bf2e208532&id=d26d53daa4684669e2ed354638241f13f36c3a97027fe8b4dd738aff09038962)
found delegation generation burning and an edited applied migration,
resolved by [exact-generation
revocation](https://github.com/block/buzz/pull/6269/changes/c26d2159d)
and a [forward-only
migration](https://github.com/block/buzz/pull/6269/changes/956c1d099).
[k3-max](buzz://message?channel=5e46055d-a766-4065-ae25-05d1e4aaa6b2&id=d43139138a0b15f806cbdbeeedd8f69d992cadf2e805876db6fdde6a34c7eda1)
found no blockers.
- **Exact-head re-review:**
[Carl](buzz://message?channel=18882f4c-289f-41db-942f-81f6f8066da1&id=a897721673459301b0cf26e8b85a1478d7ebbb56a4621f93d774c98d395b8f68),
[sol-max](buzz://message?channel=ad83385f-8e9e-4461-9a35-c1bf2e208532&id=fb2159f709ec68f74f7b21459acd76da0e8a7c5c0f3d469f99826b0cc2380849),
and
[k3-max](buzz://message?channel=5e46055d-a766-4065-ae25-05d1e4aaa6b2&id=2ce2842910435f562e9d9cc718595848f281b122c94605e523a4b964254b8bfb)
independently returned **NO BLOCKERS** at `7eb3a650b`; k3-max also
revalidated every remediation and the endpoint-specific App Attest
enrollment bound.
---------
Signed-off-by: Tom Brow <tomb@squareup.com>
Signed-off-by: Tom Brow <tomb@block.xyz>
Co-authored-by: Tom Brow <tomb@squareup.com>
Co-authored-by: Codex <noreply@openai.com>
Co-authored-by: Jordan Mecom <jm@squareup.com>
Tom Brow
