fix: direct fiat payments (#4116)

Co-authored-by: Arc <33088785+arcbtc@users.noreply.github.com>

lnbits/core/models/payments.py

@@ -275,6 +275,9 @@ class CreateInvoice(BaseModel):
     labels: list[str] = []
     external_id: str | None = Query(default=None, max_length=256)
 
+    def is_fiat_subscription(self) -> bool:
+        return (self.extra or {}).get("fiat_method") == "subscription"
+
     @validator("payment_hash")
     def check_hex(cls, v):
         if v:

lnbits/core/services/payments.py

@@ -118,6 +118,8 @@ async def create_payment_request(
     Create a lightning invoice or a fiat payment request.
     """
     if invoice_data.fiat_provider:
+        if invoice_data.is_fiat_subscription():
+            raise ValueError("Cannot create direct fiat subscription payments.")
         return await create_fiat_invoice(wallet_id, invoice_data)
 
     return await create_wallet_invoice(wallet_id, invoice_data)

tests/api/test_api.py

@@ -233,6 +233,40 @@ async def test_create_fiat_invoice(
     assert invoice["extra"]["fiat_payment_request"] == fiat_payment_request
 
 
+@pytest.mark.anyio
+async def test_create_fiat_subscription_invoice_rejected(
+    client, inkey_headers_to, mocker: MockerFixture
+):
+    fiat_mock = mocker.patch(
+        "lnbits.core.services.payments.create_fiat_invoice",
+        AsyncMock(),
+    )
+
+    response = await client.post(
+        "/api/v1/payments",
+        headers=inkey_headers_to,
+        json={
+            "unit": "USD",
+            "out": False,
+            "amount": 2100,
+            "fiat_provider": "stripe",
+            "extra": {
+                "fiat_method": "subscription",
+                "subscription": {
+                    "checking_id": "fiat_stripe_cs_paid_session",
+                    "payment_request": "",
+                },
+            },
+        },
+    )
+
+    assert response.status_code == 400
+    assert response.json()["detail"] == (
+        "Cannot create direct fiat subscription payments."
+    )
+    fiat_mock.assert_not_awaited()
+
+
 @pytest.mark.anyio
 @pytest.mark.parametrize("currency", ("msat", "RRR"))
 async def test_create_invoice_validates_used_currency(

tests/unit/test_services_payments.py

@@ -75,6 +75,39 @@ async def test_create_payment_request_routes_by_invoice_type(mocker: MockerFixtu
     fiat_mock.assert_awaited_once()
 
 
+@pytest.mark.anyio
+@pytest.mark.parametrize("fiat_provider", ("stripe", "square", "paypal"))
+async def test_create_payment_request_rejects_fiat_subscription(
+    fiat_provider: str, mocker: MockerFixture
+):
+    fiat_mock = mocker.patch(
+        "lnbits.core.services.payments.create_fiat_invoice",
+        mocker.AsyncMock(),
+    )
+
+    with pytest.raises(
+        ValueError,
+        match="Cannot create direct fiat subscription payments.",
+    ):
+        await create_payment_request(
+            "wallet-1",
+            CreateInvoice(
+                unit="USD",
+                amount=2100,
+                fiat_provider=fiat_provider,
+                extra={
+                    "fiat_method": "subscription",
+                    "subscription": {
+                        "checking_id": "fiat_stripe_cs_paid_session",
+                        "payment_request": "",
+                    },
+                },
+            ),
+        )
+
+    fiat_mock.assert_not_awaited()
+
+
 @pytest.mark.anyio
 async def test_update_pending_payment_and_bulk_pending_updates(mocker: MockerFixture):
     wallet = await _create_wallet()