Extension: LNURLw webhook_url (#610)

* LNURLw web_hook

* crlf -> lf

* Fix typo

* LNURLw webhook api doc

lnbits/extensions/withdraw/lnurl.py

@@ -1,4 +1,7 @@
 import json
+import traceback
+import httpx
+
 from datetime import datetime
 from http import HTTPStatus
 
@@ -103,17 +106,35 @@ async def api_lnurl_callback(
         await update_withdraw_link(link.id, **changes)
 
         payment_request = pr
-
-        await pay_invoice(
+        
+        payment_hash = await pay_invoice(
             wallet_id=link.wallet,
             payment_request=payment_request,
             max_sat=link.max_withdrawable,
             extra={"tag": "withdraw"},
         )
+
+        if link.webhook_url:
+            async with httpx.AsyncClient() as client:
+                try:
+                    r = await client.post(
+                        link.webhook_url,
+                        json={
+                            "payment_hash": payment_hash,
+                            "payment_request": payment_request,
+                            "lnurlw": link.id,
+                        },
+                        timeout=40,
+                    )
+                except Exception as exc:
+                    # webhook fails shouldn't cause the lnurlw to fail since invoice is already paid
+                    print("Caught exception when dispatching webhook url:", exc)
+
         return {"status": "OK"}
 
     except Exception as e:
         await update_withdraw_link(link.id, **changesback)
+        print(traceback.format_exc())
         return {"status": "ERROR", "reason": "Link not working"}