补充业务异常

book/v3/controllers/book.go

@@ -4,7 +4,9 @@ import (
 	"context"
 
 	"122.51.31.227/go-course/go18/book/v3/config"
+	"122.51.31.227/go-course/go18/book/v3/exception"
 	"122.51.31.227/go-course/go18/book/v3/models"
+	"gorm.io/gorm"
 )
 
 var Book = &BookController{}
@@ -37,6 +39,9 @@ func (c *BookController) GetBook(ctx context.Context, in *GetBookRequest) (*mode
 	bookInstance := &models.Book{}
 	// 需要从数据库中获取一个对象
 	if err := config.DB().Where("id = ?", in.BookNumber).Take(bookInstance).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return nil, exception.ErrNotFound("book number: %d not found", in.BookNumber)
+		}
 		return nil, err
 	}
 

book/v3/controllers/comment.go

@@ -20,6 +20,10 @@ func (c *CommentController) AddComment(ctx context.Context, in *AddCommentReques
 	// 业务处理的细节
 	// 多个业务模块 进行交互
 	book, err := Book.GetBook(ctx, NewGetBookRequest(in.BookNumber))
+
+	// if exception.IsApiException(err, exception.CODE_NOT_FOUND) {
+
+	// }
 	if err != nil {
 		// 获取查询不到报错
 		return nil, err

book/v3/exception/README.md

@@ -0,0 +1,88 @@
+# 业务异常
+
+## 异常的定义
+
+```go
+// 用于描述业务异常
+// 实现自定义异常
+// return error
+type ApiException struct {
+	// 业务异常的编码, 50001 表示Token过期
+	Code int `json:"code"`
+	// 异常描述信息
+	Message string `json:"message"`
+	// 不会出现在Boyd里面, 序列画成JSON, http response 进行set
+	HttpCode int `json:"-"`
+}
+
+// The error built-in interface type is the conventional interface for
+// representing an error condition, with the nil value representing no error.
+//
+//	type error interface {
+//		Error() string
+//	}
+func (e *ApiException) Error() string {
+	return e.Message
+}
+```
+
+## 异常的比对, 对于 Error Code 更加准确
+
+```go
+// 通过 Code 来比较错误
+func IsApiException(err error, code int) bool {
+	var apiErr *ApiException
+	if errors.As(err, &apiErr) {
+		return apiErr.Code == code
+	}
+	return false
+}
+```
+
+## 内置了一些全局异常，方便快速使用
+
+```go
+func ErrServerInternal(format string, a ...any) *ApiException {
+	return &ApiException{
+		Code:     CODE_SERVER_ERROR,
+		Message:  fmt.Sprintf(format, a...),
+		HttpCode: 500,
+	}
+}
+
+func ErrNotFound(format string, a ...any) *ApiException {
+	return &ApiException{
+		Code:     CODE_NOT_FOUND,
+		Message:  fmt.Sprintf(format, a...),
+		HttpCode: 404,
+	}
+}
+
+func ErrValidateFailed(format string, a ...any) *ApiException {
+	return &ApiException{
+		Code:     CODE_PARAM_INVALIDATE,
+		Message:  fmt.Sprintf(format, a...),
+		HttpCode: 400,
+	}
+}
+```
+
+## 返回自定义异常
+
+```go
+	// 需要从数据库中获取一个对象
+	if err := config.DB().Where("id = ?", in.BookNumber).Take(bookInstance).Error; err != nil {
+		if err == gorm.ErrRecordNotFound {
+			return nil, exception.ErrNotFound("book number: %d not found", in.BookNumber)
+		}
+		return nil, err
+	}
+```
+
+## 判断自定义异常
+
+```go
+if exception.IsApiException(err, exception.CODE_NOT_FOUND) {
+    // 异常处理逻辑
+}
+```

book/v3/exception/common.go

@@ -0,0 +1,35 @@
+package exception
+
+import (
+	"fmt"
+)
+
+const (
+	CODE_SERVER_ERROR     = 5000
+	CODE_NOT_FOUND        = 404
+	CODE_PARAM_INVALIDATE = 400
+)
+
+func ErrServerInternal(format string, a ...any) *ApiException {
+	return &ApiException{
+		Code:     CODE_SERVER_ERROR,
+		Message:  fmt.Sprintf(format, a...),
+		HttpCode: 500,
+	}
+}
+
+func ErrNotFound(format string, a ...any) *ApiException {
+	return &ApiException{
+		Code:     CODE_NOT_FOUND,
+		Message:  fmt.Sprintf(format, a...),
+		HttpCode: 404,
+	}
+}
+
+func ErrValidateFailed(format string, a ...any) *ApiException {
+	return &ApiException{
+		Code:     CODE_PARAM_INVALIDATE,
+		Message:  fmt.Sprintf(format, a...),
+		HttpCode: 400,
+	}
+}

book/v3/exception/exception.go

@@ -0,0 +1,59 @@
+package exception
+
+import (
+	"errors"
+
+	"github.com/infraboard/mcube/v2/tools/pretty"
+)
+
+func NewApiException(code int, message string) *ApiException {
+	return &ApiException{
+		Code:    code,
+		Message: message,
+	}
+}
+
+// 用于描述业务异常
+// 实现自定义异常
+// return error
+type ApiException struct {
+	// 业务异常的编码, 50001 表示Token过期
+	Code int `json:"code"`
+	// 异常描述信息
+	Message string `json:"message"`
+	// 不会出现在Boyd里面, 序列画成JSON, http response 进行set
+	HttpCode int `json:"-"`
+}
+
+// The error built-in interface type is the conventional interface for
+// representing an error condition, with the nil value representing no error.
+//
+//	type error interface {
+//		Error() string
+//	}
+func (e *ApiException) Error() string {
+	return e.Message
+}
+
+func (e *ApiException) String() string {
+	return pretty.ToJSON(e)
+}
+
+func (e *ApiException) WithMessage(msg string) *ApiException {
+	e.Message = msg
+	return e
+}
+
+func (e *ApiException) WithHttpCode(httpCode int) *ApiException {
+	e.HttpCode = httpCode
+	return e
+}
+
+// 通过 Code 来比较错误
+func IsApiException(err error, code int) bool {
+	var apiErr *ApiException
+	if errors.As(err, &apiErr) {
+		return apiErr.Code == code
+	}
+	return false
+}

book/v3/exception/exception_test.go

@@ -0,0 +1,24 @@
+package exception_test
+
+import (
+	"testing"
+
+	"122.51.31.227/go-course/go18/book/v3/exception"
+)
+
+func CheckIsError() error {
+	return exception.ErrNotFound("book %d not found", 1)
+}
+
+func TestException(t *testing.T) {
+	err := CheckIsError()
+	t.Log(err)
+
+	// 怎么获取ErrorCode, 断言这个接口的对象的具体类型
+	if v, ok := err.(*exception.ApiException); ok {
+		t.Log(v.Code)
+		t.Log(v.String())
+	}
+
+	t.Log(exception.IsApiException(err, exception.CODE_NOT_FOUND))
+}