SSE endpoint for paid invoices.

also move very essential stuff from core/tasks.py to tasks.py so things
are more organized.

lnbits/core/tasks.py

@@ -1,78 +1,15 @@
 import trio  # type: ignore
-from http import HTTPStatus
-from typing import Optional, Tuple, List, Callable, Awaitable
-from quart import Request, g
-from quart_trio import QuartTrio
-from werkzeug.datastructures import Headers
-
-from lnbits.db import open_db, open_ext_db
-from lnbits.settings import WALLET
+from typing import List
 
 from .models import Payment
-from .crud import get_standalone_payment
 
-main_app: Optional[QuartTrio] = None
+sse_listeners: List[trio.MemorySendChannel] = []
 
 
-def grab_app_for_later(state):
-    global main_app
-    main_app = state.app
-
-
-async def send_push_promise(a, b) -> None:
-    pass
-
-
-async def run_on_pseudo_request(func: Callable, *args):
-    fk = Request(
-        "GET",
-        "http",
-        "/background/pseudo",
-        b"",
-        Headers([("host", "lnbits.background")]),
-        "",
-        "1.1",
-        send_push_promise=send_push_promise,
-    )
-    assert main_app
-
-    async def run():
-        async with main_app.request_context(fk):
-            with open_db() as g.db:  # type: ignore
-                await func(*args)
-
-    async with trio.open_nursery() as nursery:
-        nursery.start_soon(run)
-
-
-invoice_listeners: List[Tuple[str, Callable[[Payment], Awaitable[None]]]] = []
-
-
-def register_invoice_listener(ext_name: str, cb: Callable[[Payment], Awaitable[None]]):
-    """
-    A method intended for extensions to call when they want to be notified about
-    new invoice payments incoming.
-    """
-    print(f"registering {ext_name} invoice_listener callback: {cb}")
-    invoice_listeners.append((ext_name, cb))
-
-
-async def webhook_handler():
-    handler = getattr(WALLET, "webhook_listener", None)
-    if handler:
-        return await handler()
-    return "", HTTPStatus.NO_CONTENT
-
-
-async def invoice_listener():
-    async for checking_id in WALLET.paid_invoices_stream():
-        await run_on_pseudo_request(invoice_callback_dispatcher, checking_id)
-
-
-async def invoice_callback_dispatcher(checking_id: str):
-    payment = get_standalone_payment(checking_id)
-    if payment and payment.is_in:
-        payment.set_pending(False)
-        for ext_name, cb in invoice_listeners:
-            with open_ext_db(ext_name) as g.ext_db:  # type: ignore
-                await cb(payment)
+async def on_invoice_paid(payment: Payment):
+    for send_channel in sse_listeners:
+        try:
+            send_channel.send_nowait(payment)
+        except trio.WouldBlock:
+            print("removing sse listener", send_channel)
+            sse_listeners.remove(send_channel)