Improve CORS origin handling; extend invoice repo/service and payments dispatch; rate limit and nginx config updates

Made-with: Love

internal/http/middleware/cors.go

@@ -1,18 +1,70 @@
 package middleware
 
-import "net/http"
+import (
+	"net/http"
+	"net/url"
+	"strings"
 
-func CORS(next http.Handler) http.Handler {
-	return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
-		h := w.Header()
-		h.Set("Access-Control-Allow-Origin", "*")
-		h.Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
-		h.Set("Access-Control-Allow-Headers", "Content-Type, X-API-Key, Authorization")
-		h.Set("Access-Control-Max-Age", "86400")
-		if r.Method == http.MethodOptions {
-			w.WriteHeader(http.StatusNoContent)
-			return
-		}
-		next.ServeHTTP(w, r)
-	})
+	"github.com/noderunners/nip05api/internal/config"
+)
+
+// CORS sends at most one Access-Control-Allow-Origin value (echo of request Origin).
+// Configure FRONTEND_URL, optional CORS_ORIGINS, and CORS_ALLOW_LOCALHOST / CORS_ALLOW_CREDENTIALS.
+func CORS(cfg *config.Config) func(http.Handler) http.Handler {
+	return func(next http.Handler) http.Handler {
+		return http.HandlerFunc(func(w http.ResponseWriter, r *http.Request) {
+			origin := r.Header.Get("Origin")
+
+			if origin != "" && originAllowed(origin, cfg) {
+				h := w.Header()
+				h.Set("Access-Control-Allow-Origin", origin)
+				h.Set("Access-Control-Allow-Methods", "GET, POST, PUT, DELETE, OPTIONS")
+				h.Set("Access-Control-Allow-Headers", "Content-Type, X-API-Key, Authorization")
+				h.Set("Access-Control-Max-Age", "86400")
+				if cfg.CORSAllowCredentials {
+					h.Set("Access-Control-Allow-Credentials", "true")
+				}
+			}
+
+			if r.Method == http.MethodOptions {
+				w.WriteHeader(http.StatusNoContent)
+				return
+			}
+
+			next.ServeHTTP(w, r)
+		})
+	}
+}
+
+func originAllowed(origin string, cfg *config.Config) bool {
+	if origin == "" {
+		return false
+	}
+
+	u, err := url.Parse(origin)
+	if err != nil || u.Scheme == "" || u.Host == "" {
+		return false
+	}
+
+	for _, allowed := range cfg.CORSExactOrigins() {
+		if origin == allowed {
+			return true
+		}
+	}
+
+	if cfg.CORSAllowLocalhost && isLoopbackOrigin(u) {
+		return true
+	}
+
+	return false
+}
+
+func isLoopbackOrigin(u *url.URL) bool {
+	host := strings.TrimSuffix(strings.ToLower(u.Hostname()), ".")
+	switch host {
+	case "localhost", "127.0.0.1", "::1":
+		return true
+	default:
+		return false
+	}
 }