fix(t231): expose freight preflight errors

backend-api/internal/transport/httpapi/admin_handlers.go

@@ -845,6 +845,18 @@ func writeUsecaseError(ctx *gin.Context, err error) {
 	case usecase.ErrorKindUnavailable:
 		status = http.StatusServiceUnavailable
 	}
+	switch typed.Code {
+	case "ERP_NOT_CONFIGURED", "ERP_LOGIN_REJECTED":
+		status = http.StatusUnprocessableEntity
+	case "ERP_RESPONSE_INVALID":
+		status = http.StatusBadGateway
+	case "OCR_SERVICE_INVALID", "ERP_UNAVAILABLE":
+		status = http.StatusServiceUnavailable
+	}
+	message := typed.Message
+	if preflightMessage, ok := freightPreflightPublicMessage(typed.Code); ok {
+		message = preflightMessage
+	}
 	details := gin.H{}
 	if len(typed.Fields) > 0 {
 		details["fields"] = typed.Fields
@@ -853,12 +865,29 @@ func writeUsecaseError(ctx *gin.Context, err error) {
 		ctx,
 		status,
 		typed.Code,
-		typed.Message,
+		message,
 		typed.Retryable,
 		details,
 	)
 }
 
+func freightPreflightPublicMessage(code string) (string, bool) {
+	switch code {
+	case "ERP_NOT_CONFIGURED":
+		return "ERP credentials are not configured", true
+	case "ERP_LOGIN_REJECTED":
+		return "ERP login was rejected", true
+	case "ERP_RESPONSE_INVALID":
+		return "ERP response is invalid", true
+	case "OCR_SERVICE_INVALID":
+		return "OCR service is invalid", true
+	case "ERP_UNAVAILABLE":
+		return "ERP is temporarily unavailable", true
+	default:
+		return "", false
+	}
+}
+
 func writePublicError(
 	ctx *gin.Context,
 	status int,

backend-api/internal/transport/httpapi/preflight_error_test.go

@@ -0,0 +1,46 @@
+package httpapi
+
+import (
+	"net/http"
+	"net/http/httptest"
+	"strings"
+	"testing"
+
+	"cmroubao/backend-api/internal/usecase"
+
+	"github.com/gin-gonic/gin"
+)
+
+func TestWriteUsecaseErrorUsesPreflightStatusAndCode(t *testing.T) {
+	testCases := []struct {
+		code   string
+		status int
+	}{
+		{"ERP_NOT_CONFIGURED", http.StatusUnprocessableEntity},
+		{"ERP_LOGIN_REJECTED", http.StatusUnprocessableEntity},
+		{"ERP_RESPONSE_INVALID", http.StatusBadGateway},
+		{"OCR_SERVICE_INVALID", http.StatusServiceUnavailable},
+		{"ERP_UNAVAILABLE", http.StatusServiceUnavailable},
+	}
+	for _, testCase := range testCases {
+		t.Run(testCase.code, func(t *testing.T) {
+			gin.SetMode(gin.TestMode)
+			router := gin.New()
+			router.GET("/test", func(ctx *gin.Context) {
+				writeUsecaseError(ctx, &usecase.Error{
+					Kind:    usecase.ErrorKindUnavailable,
+					Code:    testCase.code,
+					Message: "private upstream response is hidden",
+					Fields:  map[string]string{},
+				})
+			})
+			response := httptest.NewRecorder()
+			router.ServeHTTP(response, httptest.NewRequest(http.MethodGet, "/test", nil))
+			if response.Code != testCase.status ||
+				!strings.Contains(response.Body.String(), testCase.code) ||
+				strings.Contains(response.Body.String(), "private upstream") {
+				t.Fatalf("response = %d / %s", response.Code, response.Body)
+			}
+		})
+	}
+}