From b2fe9b03d7255b275041dfb7b11ee061cb936ca1 Mon Sep 17 00:00:00 2001
From: ekzyis <ekzyis@ekzyis.com>
Date: Sat, 9 Sep 2023 22:52:51 +0200
Subject: [PATCH] Use 405 Method Not Allowed if no LND connection exists

---
 src/lnd.go    | 22 ++++++++++++++++++++--
 src/router.go | 15 ++++++++-------
 src/server.go |  6 +++---
 3 files changed, 31 insertions(+), 12 deletions(-)

diff --git a/src/lnd.go b/src/lnd.go
index d07e59f..d236066 100644
--- a/src/lnd.go
+++ b/src/lnd.go
@@ -21,6 +21,7 @@ var (
 	LndMacaroonDir string
 	LndHost        string
 	lnd            *LndClient
+	lndEnabled     bool
 )
 
 type LndClient struct {
@@ -36,16 +37,29 @@ func init() {
 	flag.StringVar(&LndMacaroonDir, "LND_MACAROON_DIR", "", "LND macaroon directory")
 	flag.StringVar(&LndHost, "LND_HOST", "localhost:10001", "LND gRPC server address")
 	flag.Parse()
+	lndEnabled = false
 	rpcClient, err := lndclient.NewBasicClient(LndHost, LndCert, LndMacaroonDir, "regtest")
 	if err != nil {
-		panic(err)
+		log.Println(err)
+		return
 	}
 	lnd = &LndClient{LightningClient: rpcClient}
 	if info, err := lnd.GetInfo(context.TODO(), &lnrpc.GetInfoRequest{}); err != nil {
-		panic(err)
+		log.Printf("LND connection error: %v\n", err)
+		return
 	} else {
 		version := strings.Split(info.Version, " ")[0]
 		log.Printf("Connected to %s running LND v%s", LndHost, version)
+		lndEnabled = true
+	}
+}
+
+func lndGuard(next echo.HandlerFunc) echo.HandlerFunc {
+	return func(c echo.Context) error {
+		if lndEnabled {
+			return next(c)
+		}
+		return serveError(c, 405)
 	}
 }
 
@@ -77,6 +91,10 @@ func (lnd *LndClient) CreateInvoice(pubkey string, msats int) (*Invoice, error)
 }
 
 func (lnd *LndClient) CheckInvoice(hash string) {
+	if !lndEnabled {
+		log.Printf("LND disabled, skipping checking invoice: hash=%s", hash)
+		return
+	}
 	for {
 		log.Printf("lookup invoice: hash=%s", hash)
 		invoice, err := lnd.LookupInvoice(context.TODO(), &lnrpc.PaymentHash{RHashStr: hash})
diff --git a/src/router.go b/src/router.go
index 85dbab3..82e00dd 100644
--- a/src/router.go
+++ b/src/router.go
@@ -71,17 +71,18 @@ func index(c echo.Context) error {
 	return c.Render(http.StatusOK, "index.html", data)
 }
 
-func serve500(c echo.Context) {
-	f, err := os.Open("public/500.html")
+func serveError(c echo.Context, code int) error {
+	f, err := os.Open(fmt.Sprintf("public/%d.html", code))
 	if err != nil {
 		c.Logger().Error(err)
-		return
+		return err
 	}
-	err = c.Stream(500, "text/html", f)
+	err = c.Stream(code, "text/html", f)
 	if err != nil {
 		c.Logger().Error(err)
-		return
+		return err
 	}
+	return nil
 }
 
 func httpErrorHandler(err error, c echo.Context) {
@@ -95,13 +96,13 @@ func httpErrorHandler(err error, c echo.Context) {
 	f, err := os.Open(filePath)
 	if err != nil {
 		c.Logger().Error(err)
-		serve500(c)
+		serveError(c, 500)
 		return
 	}
 	err = c.Stream(code, "text/html", f)
 	if err != nil {
 		c.Logger().Error(err)
-		serve500(c)
+		serveError(c, 500)
 		return
 	}
 }
diff --git a/src/server.go b/src/server.go
index fea6638..4d60c3d 100644
--- a/src/server.go
+++ b/src/server.go
@@ -65,9 +65,9 @@ func main() {
 	e.POST("/logout", logout)
 	e.GET("/user", sessionGuard(user))
 	e.GET("/market/:id", sessionGuard(market))
-	e.POST("/market/:id/order", sessionGuard(order))
-	e.GET("/invoice/:id", sessionGuard(invoice))
-	e.GET("/api/invoice/:id", sessionGuard(invoiceStatus))
+	e.POST("/market/:id/order", sessionGuard(lndGuard(order)))
+	e.GET("/invoice/:id", sessionGuard(lndGuard(invoice)))
+	e.GET("/api/invoice/:id", sessionGuard(lndGuard(invoiceStatus)))
 	e.Use(middleware.LoggerWithConfig(middleware.LoggerConfig{
 		Format:           "${time_custom} ${method} ${uri} ${status}\n",
 		CustomTimeFormat: "2006-01-02 15:04:05.00000-0700",