05-自定义接口的返回格式

HTTP错误返回结构自定义

• 默认返回处理： transport/http/codec.go

规范

• goole 错误码

• kratos errors 源码

  • types.go 常见错误方法，判断错误
  • wrap.go 标准错误包装，格式转换 AS

• kratos errors 文档

使用

• 安装包

  # protoc-gen-go-errors
  go install github.com/go-kratos/kratos/cmd/protoc-gen-go-errors/v2@latest

• 编写

  USER_NOT_FOUND = 0 [(errors.code) = 404];

• 运行

  # 命令
  make errors

• 结果

  // 错误判断
  func IsUserNotFound(err error) bool {
    if err == nil {
        return false
    }
    e := errors.FromError(err)
    return e.Reason == ErrorReason_USER_NOT_FOUND.String() && e.Code == 404
  }
  // 错误封装，避免手写
  func ErrorUserNotFound(format string, args ...interface{}) *errors.Error {
    return errors.New(404, ErrorReason_USER_NOT_FOUND.String(), fmt.Sprintf(format, args...))
  }

• 使用
  最下方的标题-使用方式

代码

encoder.go

• 路径 internal\server\encoder.go

package server

import (
    nethttp "net/http"

    // "kratos-realworld/internal/errors"

    "github.com/go-kratos/kratos/v2/errors"
    "github.com/go-kratos/kratos/v2/transport/http"
    // "github.com/go-kratos/kratos/v2/transport/http"
)

/* 中间件调用 */
func errorEncoder(w nethttp.ResponseWriter, r *nethttp.Request, err error) {
    se := errors.FromError(err)
    codec, _ := http.CodecForRequest(r, "Accept")
    body, err := codec.Marshal((se))
    if err != nil {
        w.WriteHeader(500)
        return
    }
    w.Header().Set("Content-Type", "application/"+codec.Name())
    if se.Code > 99 && se.Code < 600 {
        w.WriteHeader(int(se.Code))
    } else {
        w.WriteHeader(500)
    }

    _, _ = w.Write(body)
}

error_encoder.go

• internal\errors\error_encoder.go

package errors

import (
    "fmt"
    "github.com/go-kratos/kratos/v2/errors"
)


func NewHTTPError(code int, field string, detail string) *HTTPError {
    return &HTTPError{
        Code: code,
        Errors: map[string][]string{
            field: {detail},
        },
    }
}

type HTTPError struct {
    Errors map[string][]string `json:"errors"`

    Code int `json:"-"`
}

func (e *HTTPError) Error() string {
    return fmt.Sprintf("HTTPError: %d", e.Code)
}

func FromError(err error) *HTTPError {
    if err == nil {
        return nil
    }
    if se := new(HTTPError); errors.As(err, &se) {
        return se
    }
    // 修改错误格式
    if se := new(errors.Error); errors.As(err, &se) {
        return NewHTTPError(int(se.Code), se.Reason, se.Message)
    }
    return NewHTTPError(500, "internal", "error")
}