From ff87319a741fda1d321187d5b6a6c37666d958f9 Mon Sep 17 00:00:00 2001
From: Dennis Reimann <mail@dennisreimann.de>
Date: Mon, 23 Nov 2020 06:40:13 +0100
Subject: [PATCH] API: Handle lightning invoice creation errors (#2070)

Catches LightningClient exceptions and responds with a detailed API error (400) instead of a generic server failure (503).
---
 .../GreenField/LightningNodeApiController.cs  | 28 +++++++++++++++----
 .../swagger.template.lightning.internal.json  | 10 +++++++
 .../v1/swagger.template.lightning.store.json  | 10 +++++++
 3 files changed, 42 insertions(+), 6 deletions(-)

diff --git a/BTCPayServer/Controllers/GreenField/LightningNodeApiController.cs b/BTCPayServer/Controllers/GreenField/LightningNodeApiController.cs
index d8eb1079b..5dcfef4bd 100644
--- a/BTCPayServer/Controllers/GreenField/LightningNodeApiController.cs
+++ b/BTCPayServer/Controllers/GreenField/LightningNodeApiController.cs
@@ -263,13 +263,29 @@ namespace BTCPayServer.Controllers.GreenField
             {
                 return this.CreateValidationError(ModelState);
             }
-            var invoice = await lightningClient.CreateInvoice(
-                new CreateInvoiceParams(request.Amount, request.Description, request.Expiry)
+
+            try
+            {
+                var invoice = await lightningClient.CreateInvoice(
+                    new CreateInvoiceParams(request.Amount, request.Description, request.Expiry)
+                    {
+                        PrivateRouteHints = request.PrivateRouteHints
+                    },
+                    CancellationToken.None);
+                return Ok(ToModel(invoice));
+            }
+            catch (Exception ex)
+            {
+                var nameSpace = ex.GetType().Namespace;
+                var isLnClientError = nameSpace != null &&
+                                      nameSpace.StartsWith("BTCPayServer.Lightning",
+                                          StringComparison.OrdinalIgnoreCase);
+                if (isLnClientError)
                 {
-                    PrivateRouteHints = request.PrivateRouteHints
-                },
-                CancellationToken.None);
-            return Ok(ToModel(invoice));
+                    return this.CreateAPIError("invoice-error", ex.Message);
+                }
+                throw;
+            }
         }
 
         private LightningInvoiceData ToModel(LightningInvoice invoice)
diff --git a/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.internal.json b/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.internal.json
index 8d9b0bce0..0650e111b 100644
--- a/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.internal.json
+++ b/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.internal.json
@@ -433,6 +433,16 @@
                             }
                         }
                     },
+                    "400": {
+                        "description": "Wellknown error codes are: `invoice-error`",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "$ref": "#/components/schemas/ProblemDetails"
+                                }
+                            }
+                        }
+                    },
                     "503": {
                         "description": "Unable to access the lightning node"
                     },
diff --git a/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.store.json b/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.store.json
index b166fd982..be94d7104 100644
--- a/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.store.json
+++ b/BTCPayServer/wwwroot/swagger/v1/swagger.template.lightning.store.json
@@ -509,6 +509,16 @@
                             }
                         }
                     },
+                    "400": {
+                        "description": "Wellknown error codes are: `invoice-error`",
+                        "content": {
+                            "application/json": {
+                                "schema": {
+                                    "$ref": "#/components/schemas/ProblemDetails"
+                                }
+                            }
+                        }
+                    },
                     "503": {
                         "description": "Unable to access the lightning node"
                     },