新增单词管理后台,分类有单词时禁止删除,支持 Docker 一键部署

Co-Authored-By: Claude Opus 4.7 <noreply@anthropic.com>

backend/README.md

@@ -35,7 +35,7 @@ make test
 - `POST   /api/v1/categories`
 - `GET    /api/v1/categories/:id`
 - `PUT    /api/v1/categories/:id`
-- `DELETE /api/v1/categories/:id`
+- `DELETE /api/v1/categories/:id`（分类下仍有单词时返回 409，code 10005）
 
 ### Words
 

backend/internal/handlers/response.go

@@ -5,6 +5,7 @@ import (
 	"errors"
 	"net/http"
 
+	"github.com/fish/language/backend/internal/services"
 	"github.com/jackc/pgx/v5"
 )
 
@@ -30,6 +31,9 @@ func MapError(err error) (status int, code int, message string) {
 	if errors.Is(err, pgx.ErrNoRows) {
 		return http.StatusNotFound, 10001, "resource not found"
 	}
+	if errors.Is(err, services.ErrCategoryNotEmpty) {
+		return http.StatusConflict, 10005, "category has words and cannot be deleted"
+	}
 	return http.StatusInternalServerError, 10000, "internal server error"
 }
 

backend/internal/services/category_service.go

@@ -2,11 +2,15 @@ package services
 
 import (
 	"context"
+	"errors"
 
 	"github.com/fish/language/backend/internal/models"
 	"github.com/fish/language/backend/internal/repository/queries"
 )
 
+// ErrCategoryNotEmpty is returned when deleting a category that still has words.
+var ErrCategoryNotEmpty = errors.New("category has words")
+
 // CategoryService handles business logic for categories.
 type CategoryService struct {
 	q *queries.Queries
@@ -64,8 +68,15 @@ func (s *CategoryService) Update(ctx context.Context, id int32, req models.Updat
 	return toCategory(row), nil
 }
 
-// Delete removes a category by id.
+// Delete removes a category by id. It refuses to delete a category that still has words.
 func (s *CategoryService) Delete(ctx context.Context, id int32) error {
+	count, err := s.q.CountWords(ctx, queries.CountWordsParams{CategoryID: id})
+	if err != nil {
+		return err
+	}
+	if count > 0 {
+		return ErrCategoryNotEmpty
+	}
 	return s.q.DeleteCategory(ctx, id)
 }