refactor: catch payment and invoice error at faspi exceptionhandler level (#2484)

refactor exceptionhandlers into `exception.py` also now always throw
payment error when pay_invoice and invoice errors when create_invoice.

return a status flag with the detailed error message. with a 520
response

lnbits/app.py

@@ -4,22 +4,17 @@ import importlib
 import os
 import shutil
 import sys
-import traceback
 from contextlib import asynccontextmanager
-from http import HTTPStatus
 from pathlib import Path
 from typing import Callable, List, Optional
 
-from fastapi import FastAPI, HTTPException, Request
+from fastapi import FastAPI
-from fastapi.exceptions import RequestValidationError
 from fastapi.middleware.cors import CORSMiddleware
-from fastapi.responses import RedirectResponse
 from fastapi.staticfiles import StaticFiles
 from loguru import logger
 from slowapi import Limiter
 from slowapi.util import get_remote_address
 from starlette.middleware.sessions import SessionMiddleware
-from starlette.responses import JSONResponse
 
 from lnbits.core.crud import get_dbversions, get_installed_extensions
 from lnbits.core.helpers import migrate_extension_database
@@ -27,6 +22,7 @@ from lnbits.core.tasks import (  # watchdog_task
     killswitch_task,
     wait_for_paid_invoices,
 )
+from lnbits.exceptions import register_exception_handlers
 from lnbits.settings import settings
 from lnbits.tasks import (
     cancel_all_tasks,
@@ -53,7 +49,6 @@ from .extension_manager import (
     get_valid_extensions,
     version_parse,
 )
-from .helpers import template_renderer
 from .middleware import (
     CustomGZipMiddleware,
     ExtensionsRedirectMiddleware,
@@ -429,82 +424,3 @@ def register_async_tasks():
     if settings.lnbits_admin_ui:
         server_log_task = initialize_server_websocket_logger()
         create_permanent_task(server_log_task)
-
-
-def register_exception_handlers(app: FastAPI):
-    @app.exception_handler(Exception)
-    async def exception_handler(request: Request, exc: Exception):
-        etype, _, tb = sys.exc_info()
-        traceback.print_exception(etype, exc, tb)
-        logger.error(f"Exception: {exc!s}")
-        # Only the browser sends "text/html" request
-        # not fail proof, but everything else get's a JSON response
-        if (
-            request.headers
-            and "accept" in request.headers
-            and "text/html" in request.headers["accept"]
-        ):
-            return template_renderer().TemplateResponse(
-                request, "error.html", {"err": f"Error: {exc!s}"}
-            )
-
-        return JSONResponse(
-            status_code=HTTPStatus.INTERNAL_SERVER_ERROR,
-            content={"detail": str(exc)},
-        )
-
-    @app.exception_handler(RequestValidationError)
-    async def validation_exception_handler(
-        request: Request, exc: RequestValidationError
-    ):
-        logger.error(f"RequestValidationError: {exc!s}")
-        # Only the browser sends "text/html" request
-        # not fail proof, but everything else get's a JSON response
-
-        if (
-            request.headers
-            and "accept" in request.headers
-            and "text/html" in request.headers["accept"]
-        ):
-            return template_renderer().TemplateResponse(
-                request,
-                "error.html",
-                {"err": f"Error: {exc!s}"},
-            )
-
-        return JSONResponse(
-            status_code=HTTPStatus.BAD_REQUEST,
-            content={"detail": str(exc)},
-        )
-
-    @app.exception_handler(HTTPException)
-    async def http_exception_handler(request: Request, exc: HTTPException):
-        logger.error(f"HTTPException {exc.status_code}: {exc.detail}")
-        # Only the browser sends "text/html" request
-        # not fail proof, but everything else get's a JSON response
-
-        if (
-            request.headers
-            and "accept" in request.headers
-            and "text/html" in request.headers["accept"]
-        ):
-            if exc.headers and "token-expired" in exc.headers:
-                response = RedirectResponse("/")
-                response.delete_cookie("cookie_access_token")
-                response.delete_cookie("is_lnbits_user_authorized")
-                response.set_cookie("is_access_token_expired", "true")
-                return response
-
-            return template_renderer().TemplateResponse(
-                request,
-                "error.html",
-                {
-                    "request": request,
-                    "err": f"HTTP Error {exc.status_code}: {exc.detail}",
-                },
-            )
-
-        return JSONResponse(
-            status_code=exc.status_code,
-            content={"detail": exc.detail},
-        )

lnbits/core/views/payment_api.py

@@ -55,8 +55,6 @@ from ..crud import (
     update_pending_payments,
 )
 from ..services import (
-    InvoiceError,
-    PaymentError,
     check_transaction_status,
     create_invoice,
     fee_reserve_total,
@@ -150,7 +148,6 @@ async def api_payments_create_invoice(data: CreateInvoice, wallet: Wallet):
         memo = ""
 
     async with db.connect() as conn:
-        try:
         payment_hash, payment_request = await create_invoice(
             wallet_id=wallet.id,
             amount=data.amount,
@@ -170,13 +167,6 @@ async def api_payments_create_invoice(data: CreateInvoice, wallet: Wallet):
         payment_db = await get_standalone_payment(payment_hash, conn=conn)
         assert payment_db is not None, "payment not found"
         checking_id = payment_db.checking_id
-        except InvoiceError as exc:
-            return JSONResponse(
-                status_code=520,
-                content={"detail": exc.message, "status": exc.status},
-            )
-        except Exception as exc:
-            raise exc
 
     invoice = bolt11.decode(payment_request)
 
@@ -213,28 +203,6 @@ async def api_payments_create_invoice(data: CreateInvoice, wallet: Wallet):
     }
 
 
-async def api_payments_pay_invoice(
-    bolt11: str, wallet: Wallet, extra: Optional[dict] = None
-):
-    try:
-        payment_hash = await pay_invoice(
-            wallet_id=wallet.id, payment_request=bolt11, extra=extra
-        )
-    except PaymentError as exc:
-        return JSONResponse(
-            status_code=520,
-            content={"detail": exc.message, "status": exc.status},
-        )
-    except Exception as exc:
-        raise exc
-
-    return {
-        "payment_hash": payment_hash,
-        # maintain backwards compatibility with API clients:
-        "checking_id": payment_hash,
-    }
-
-
 @payment_router.post(
     "",
     summary="Create or pay an invoice",
@@ -247,6 +215,11 @@ async def api_payments_pay_invoice(
         field to supply the BOLT11 invoice to be paid.
     """,
     status_code=HTTPStatus.CREATED,
+    responses={
+        400: {"description": "Invalid BOLT11 string or missing fields."},
+        401: {"description": "Invoice (or Admin) key required."},
+        520: {"description": "Payment or Invoice error."},
+    },
 )
 async def api_payments_create(
     wallet: WalletTypeInfo = Depends(require_invoice_key),
@@ -258,9 +231,18 @@ async def api_payments_create(
                 status_code=HTTPStatus.BAD_REQUEST,
                 detail="BOLT11 string is invalid or not given",
             )
-        return await api_payments_pay_invoice(
+
-            invoice_data.bolt11, wallet.wallet, invoice_data.extra
+        payment_hash = await pay_invoice(
-        )  # admin key
+            wallet_id=wallet.wallet.id,
+            payment_request=invoice_data.bolt11,
+            extra=invoice_data.extra,
+        )
+        return {
+            "payment_hash": payment_hash,
+            # maintain backwards compatibility with API clients:
+            "checking_id": payment_hash,
+        }
+
     elif not invoice_data.out:
         # invoice key
         return await api_payments_create_invoice(invoice_data, wallet.wallet)

lnbits/exceptions.py

@@ -0,0 +1,101 @@
+import sys
+import traceback
+from http import HTTPStatus
+from typing import Optional
+
+from fastapi import FastAPI, HTTPException, Request
+from fastapi.exceptions import RequestValidationError
+from fastapi.responses import JSONResponse, RedirectResponse, Response
+from loguru import logger
+
+from lnbits.core.services import InvoiceError, PaymentError
+
+from .helpers import template_renderer
+
+
+def register_exception_handlers(app: FastAPI):
+    register_exception_handler(app)
+    register_request_validation_exception_handler(app)
+    register_http_exception_handler(app)
+    register_payment_error_handler(app)
+    register_invoice_error_handler(app)
+
+
+def render_html_error(request: Request, exc: Exception) -> Optional[Response]:
+    # Only the browser sends "text/html" request
+    # not fail proof, but everything else get's a JSON response
+    if (
+        request.headers
+        and "accept" in request.headers
+        and "text/html" in request.headers["accept"]
+    ):
+        if (
+            isinstance(exc, HTTPException)
+            and exc.headers
+            and "token-expired" in exc.headers
+        ):
+            response = RedirectResponse("/")
+            response.delete_cookie("cookie_access_token")
+            response.delete_cookie("is_lnbits_user_authorized")
+            response.set_cookie("is_access_token_expired", "true")
+            return response
+
+        return template_renderer().TemplateResponse(
+            request, "error.html", {"err": f"Error: {exc!s}"}
+        )
+
+    return None
+
+
+def register_exception_handler(app: FastAPI):
+    @app.exception_handler(Exception)
+    async def exception_handler(request: Request, exc: Exception):
+        etype, _, tb = sys.exc_info()
+        traceback.print_exception(etype, exc, tb)
+        logger.error(f"Exception: {exc!s}")
+        return render_html_error(request, exc) or JSONResponse(
+            status_code=HTTPStatus.INTERNAL_SERVER_ERROR,
+            content={"detail": str(exc)},
+        )
+
+
+def register_request_validation_exception_handler(app: FastAPI):
+    @app.exception_handler(RequestValidationError)
+    async def validation_exception_handler(
+        request: Request, exc: RequestValidationError
+    ):
+        logger.error(f"RequestValidationError: {exc!s}")
+        return render_html_error(request, exc) or JSONResponse(
+            status_code=HTTPStatus.BAD_REQUEST,
+            content={"detail": str(exc)},
+        )
+
+
+def register_http_exception_handler(app: FastAPI):
+    @app.exception_handler(HTTPException)
+    async def http_exception_handler(request: Request, exc: HTTPException):
+        logger.error(f"HTTPException {exc.status_code}: {exc.detail}")
+        return render_html_error(request, exc) or JSONResponse(
+            status_code=exc.status_code,
+            content={"detail": exc.detail},
+        )
+
+
+def register_payment_error_handler(app: FastAPI):
+    @app.exception_handler(PaymentError)
+    async def payment_error_handler(request: Request, exc: PaymentError):
+        logger.error(f"PaymentError: {exc.message}, {exc.status}")
+        return JSONResponse(
+            status_code=520,
+            content={"detail": exc.message, "status": exc.status},
+        )
+
+
+def register_invoice_error_handler(app: FastAPI):
+    @app.exception_handler(InvoiceError)
+    async def invoice_error_handler(request: Request, exc: InvoiceError):
+        logger.error(f"InvoiceError: {exc.message}, Status: {exc.status}")
+        return JSONResponse(
+            status_code=520,
+            content={"detail": exc.message, "status": exc.status},
+        )