From 2552fd8fc9538c375e4c4795d1a2381bfaaa7017 Mon Sep 17 00:00:00 2001
From: fiatjaf <fiatjaf@alhur.es>
Date: Thu, 22 Oct 2020 15:36:37 -0300
Subject: [PATCH] internal payments get reported on async listeners.

---
 lnbits/app.py           |  3 ++-
 lnbits/core/services.py | 17 +++++++++++++----
 lnbits/tasks.py         |  8 ++++++++
 3 files changed, 23 insertions(+), 5 deletions(-)

diff --git a/lnbits/app.py b/lnbits/app.py
index 7a30e1529..8528b898a 100644
--- a/lnbits/app.py
+++ b/lnbits/app.py
@@ -12,7 +12,7 @@ from .core import core_app
 from .db import open_db, open_ext_db
 from .helpers import get_valid_extensions, get_js_vendored, get_css_vendored, url_for_vendored
 from .proxy_fix import ASGIProxyFix
-from .tasks import run_deferred_async, invoice_listener, webhook_handler, grab_app_for_later
+from .tasks import run_deferred_async, invoice_listener, internal_invoice_listener, webhook_handler, grab_app_for_later
 from .settings import WALLET
 
 secure_headers = SecureHeaders(hsts=False)
@@ -128,6 +128,7 @@ def register_async_tasks(app):
     async def listeners():
         run_deferred_async(app.nursery)
         app.nursery.start_soon(invoice_listener)
+        app.nursery.start_soon(internal_invoice_listener)
 
     @app.after_serving
     async def stop_listeners():
diff --git a/lnbits/core/services.py b/lnbits/core/services.py
index e374d2d3a..cda16d22a 100644
--- a/lnbits/core/services.py
+++ b/lnbits/core/services.py
@@ -1,3 +1,4 @@
+import trio  # type: ignore
 import httpx
 from typing import Optional, Tuple, Dict
 from quart import g
@@ -89,8 +90,8 @@ def pay_invoice(
     )
 
     # check_internal() returns the checking_id of the invoice we're waiting for
-    internal = check_internal(invoice.payment_hash)
-    if internal:
+    internal_checking_id = check_internal(invoice.payment_hash)
+    if internal_checking_id:
         # create a new payment from this wallet
         create_payment(checking_id=internal_id, fee=0, pending=False, **payment_kwargs)
     else:
@@ -108,11 +109,19 @@ def pay_invoice(
     else:
         g.db.commit()
 
-    if internal:
+    if internal_checking_id:
         # mark the invoice from the other side as not pending anymore
         # so the other side only has access to his new money when we are sure
         # the payer has enough to deduct from
-        update_payment_status(checking_id=internal, pending=False)
+        update_payment_status(checking_id=internal_checking_id, pending=False)
+
+        # notify receiver asynchronously
+        from lnbits.tasks import internal_invoice_paid
+
+        try:
+            internal_invoice_paid.send_nowait(internal_checking_id)
+        except trio.WouldBlock:
+            pass
     else:
         # actually pay the external invoice
         payment: PaymentResponse = WALLET.pay_invoice(payment_request)
diff --git a/lnbits/tasks.py b/lnbits/tasks.py
index 8a1a6a127..285b7126f 100644
--- a/lnbits/tasks.py
+++ b/lnbits/tasks.py
@@ -77,6 +77,14 @@ async def webhook_handler():
     return "", HTTPStatus.NO_CONTENT
 
 
+internal_invoice_paid, internal_invoice_received = trio.open_memory_channel(0)
+
+
+async def internal_invoice_listener():
+    async for checking_id in internal_invoice_received:
+        await run_on_pseudo_request(invoice_callback_dispatcher, checking_id)
+
+
 async def invoice_listener():
     async for checking_id in WALLET.paid_invoices_stream():
         await run_on_pseudo_request(invoice_callback_dispatcher, checking_id)