fixup: Refactor LSPS5 webhook notification handling: return notification on success, remove event emission

- Change parse_webhook_notification to return the verified WebhookNotification directly, instead of emitting an event.
- Remove LSPS5ClientEvent::WebhookNotificationReceived and related event logic.
- Now, invalid signatures result in an error and notification data is not exposed to the user.
- Follows feedback to avoid requiring users to manually check a boolean for signature validity and prevents leaking invalid notifications.

Author: martinsaposnic

lightning-liquidity/src/lsps5/client.rs

@@ -451,7 +451,7 @@ where
 	fn verify_notification_signature(
 		&self, counterparty_node_id: PublicKey, signature_timestamp: &LSPSDateTime,
 		signature: &str, notification: &WebhookNotification,
-	) -> Result<bool, LSPS5ClientError> {
+	) -> Result<(), LSPS5ClientError> {
 		let now =
 			LSPSDateTime::new_from_duration_since_epoch(self.time_provider.duration_since_epoch());
 		let diff = signature_timestamp.abs_diff(now);
@@ -467,7 +467,7 @@ where
 		);
 
 		if message_signing::verify(message.as_bytes(), signature, &counterparty_node_id) {
-			Ok(true)
+			Ok(())
 		} else {
 			Err(LSPS5ClientError::InvalidSignature)
 		}
@@ -516,7 +516,7 @@ where
 	/// - `signature`: the zbase32-encoded LN signature over timestamp+body.
 	/// - `notification`: the [`WebhookNotification`] received from the LSP.
 	///
-	/// On success, emits [`LSPS5ClientEvent::WebhookNotificationReceived`].
+	/// On success, returns the received [`WebhookNotification`].
 	///
 	/// Failure reasons include:
 	/// - Timestamp too old (drift > 10 minutes)
@@ -527,36 +527,24 @@ where
 	/// event, before taking action on the notification. This guarantees that only authentic,
 	/// non-replayed notifications reach your application.
 	///
-	/// [`LSPS5ClientEvent::WebhookNotificationReceived`]: super::event::LSPS5ClientEvent::WebhookNotificationReceived
 	/// [`LSPS5ServiceEvent::SendWebhookNotification`]: super::event::LSPS5ServiceEvent::SendWebhookNotification
 	/// [`WebhookNotification`]: super::msgs::WebhookNotification
 	pub fn parse_webhook_notification(
 		&self, counterparty_node_id: PublicKey, timestamp: &LSPSDateTime, signature: &str,
 		notification: &WebhookNotification,
-	) -> Result<(), LSPS5ClientError> {
-		match self.verify_notification_signature(
+	) -> Result<WebhookNotification, LSPS5ClientError> {
+		self.verify_notification_signature(
 			counterparty_node_id,
 			timestamp,
 			signature,
 			&notification,
-		) {
-			Ok(signature_valid) => {
-				let event_queue_notifier = self.pending_events.notifier();
+		)?;
 
-				self.check_signature_exists(signature)?;
+		self.check_signature_exists(signature)?;
 
-				self.store_signature(signature.to_string());
+		self.store_signature(signature.to_string());
 
-				event_queue_notifier.enqueue(LSPS5ClientEvent::WebhookNotificationReceived {
-					counterparty_node_id,
-					notification: notification.clone(),
-					timestamp: timestamp.clone(),
-					signature_valid,
-				});
-				Ok(())
-			},
-			Err(e) => Err(e),
-		}
+		Ok(notification.clone())
 	}
 }
 

lightning-liquidity/src/lsps5/event.rs

@@ -392,42 +392,4 @@ pub enum LSPS5ClientEvent {
 		/// This can be used to track which request this event corresponds to.
 		request_id: LSPSRequestId,
 	},
-
-	/// A webhook notification was received from the LSP.
-	///
-	/// This event is triggered when the client receives and successfully
-	/// verifies a webhook notification from the LSP. This represents an
-	/// asynchronous event that the LSP is notifying the client about.
-	///
-	/// When this event occurs, the client should:
-	/// 1. Check `signature_valid` to confirm the notification is authentic
-	/// 2. Examine the `notification.method` to determine the type of notification
-	/// 3. Process the notification according to its method and parameters
-	/// 4. Update any UI or take actions based on the notification type
-	///
-	/// Common notification methods include:
-	/// - [`LSPS5WebhookRegistered`] - Initial test notification after registration
-	/// - [`LSPS5PaymentIncoming`] - Client has pending incoming payments
-	/// - [`LSPS5ExpirySoon`] - An HTLC or contract will expire soon
-	/// - [`LSPS5LiquidityManagementRequest`] - LSP needs to manage liquidity
-	/// - [`LSPS5OnionMessageIncoming`] - Client has pending onion messages
-	///
-	/// The client should reject notifications with invalid signatures or timestamps
-	/// more than 10 minutes from the current time.
-	///
-	/// [`LSPS5WebhookRegistered`]: super::msgs::WebhookNotificationMethod::LSPS5WebhookRegistered
-	/// [`LSPS5PaymentIncoming`]: super::msgs::WebhookNotificationMethod::LSPS5PaymentIncoming
-	/// [`LSPS5ExpirySoon`]: super::msgs::WebhookNotificationMethod::LSPS5ExpirySoon
-	/// [`LSPS5LiquidityManagementRequest`]: super::msgs::WebhookNotificationMethod::LSPS5LiquidityManagementRequest
-	/// [`LSPS5OnionMessageIncoming`]: super::msgs::WebhookNotificationMethod::LSPS5OnionMessageIncoming
-	WebhookNotificationReceived {
-		/// LSP node ID that sent the notification.
-		counterparty_node_id: PublicKey,
-		/// The notification with its method and parameters.
-		notification: WebhookNotification,
-		/// Timestamp of the notification.
-		timestamp: LSPSDateTime,
-		/// Whether the LSP's signature was successfully verified.
-		signature_valid: bool,
-	},
 }