定制Gin的Validator錯誤消息及響應結構

title: 定制 Gin 的 Validator 錯誤消息及響應結構
date: 2021-11-14 19:02:00
toc: true
category:

Golang
Gin
tags:
Golang
golang
Go
go
Gin
gin
Validator
validator
功能
校驗
定制
實現
響應
結構
錯誤
消息
本地化
翻譯

前言#

在使用 Golang 的 Validator (校驗) 功能時，會發現很多錯誤的提示信息都是英文的。例如

{  
    "code": -1,  
    "msg": {  
        "SingUpForm.Age": "Key: 'SingUpForm.Age' Error:Field validation for 'Age' failed on the 'gte' tag",  
        "SingUpForm.Email": "Key: 'SingUpForm.Email' Error:Field validation for 'Email' failed on the 'required' tag",  
        "SingUpForm.Name": "Key: 'SingUpForm.Name' Error:Field validation for 'Name' failed on the 'required' tag",  
        "SingUpForm.Password": "Key: 'SingUpForm.Password' Error:Field validation for 'Password' failed on the 'required' tag",  
        "SingUpForm.RePassword": "Key: 'SingUpForm.RePassword' Error:Field validation for 'RePassword' failed on the 'required' tag"  
    }  
}

這樣會造成接口調用者的閱讀困難。
翻閱官方文檔後發現翻譯的工作已經做過了，可以直接將錯誤信息修改為指定語言。

但需要注意的是，目前 go-playground/validator 只支持了 13 種語言，具體參閱官方列出的目錄：validator/translations at master · go-playground/validator

錯誤消息本地化#

直接上代碼，邏輯很清晰。每次出現錯誤信息通過 err.(validator.ValidationErrors) 轉換得到異常對象 validator.ValidationErrors，調用其 func (ve ValidationErrors) Translate(ut ut.Translator) ValidationErrorsTranslations {} 方法即可。

package main  

import (  
    "fmt"  
    "net/http"  

    "github.com/gin-gonic/gin"  
    "github.com/gin-gonic/gin/binding"  
    "github.com/go-playground/locales/en"  
    "github.com/go-playground/locales/zh"  
    ut "github.com/go-playground/universal-translator"  
    "github.com/go-playground/validator/v10"  

    en_translations "github.com/go-playground/validator/v10/translations/en"  
    zh_translations "github.com/go-playground/validator/v10/translations/zh"  
)  

// 翻譯校驗信息  
func main() {  
    if err := InitTranslate("zh"); err != nil {  
        fmt.Println("初始化翻譯器出錯")  
        return  
    }  

    r := gin.Default()  

    r.POST("/", func(c *gin.Context) {  
        var singUpForm SingUpForm  
        if err := c.ShouldBind(&singUpForm); nil != err {  
            // 出現錯誤  
            errors, ok := err.(validator.ValidationErrors)  
            if !ok {  
                c.JSON(http.StatusOK, gin.H{  
                    "code": -1,  
                    "msg":  fmt.Errorf("error getting translation of error message, %s", err.Error()),  
                })  
                return  
            }  

            c.JSON(http.StatusBadRequest, gin.H{  
                "code": -1,  
                "msg":  errors.Translate(translator),  
            })  

            return  
        }  

        c.JSON(http.StatusOK, gin.H{  
            "code": 0,  
            "msg":  "登錄成功",  
        })  
    })  

    // 監聽並在 0.0.0.0:8080 上啟動服務  
    r.Run(":8080")  
}  

type SingUpForm struct {  
    Age        uint8  `json:"age" binding:"gte=1,lte=130"`  
    Name       string `json:"name" binding:"required,min=3"`  
    Email      string `json:"email" binding:"required,email"`  
    Password   string `json:"password" binding:"required"`  
    RePassword string `json:"rePassword" binding:"required,eqfield=Password"`  
}  

// use a single instance , it caches struct info  
var (  
    uni        *ut.UniversalTranslator  
    validate   *validator.Validate  
    translator ut.Translator  
)  

func InitTranslate(locale string) (err error) {  
    // 修改 gin 框架中的 validator 引擎屬性，實現翻譯效果  
    engine, ok := binding.Validator.Engine().(*validator.Validate)  
    if !ok {  
        fmt.Println("獲取 gin 框架的 validator 出錯")  
    }  

    zhT := zh.New()  
    enT := en.New()  

    uni := ut.New(enT, zhT, enT)  

    translator, ok = uni.GetTranslator(locale)  
    if !ok {  
        return fmt.Errorf("uni.GetTranslator(%s)", locale)  
    }  

    switch locale {  
    case "en":  
        en_translations.RegisterDefaultTranslations(engine, translator)  
    case "zh":  
        zh_translations.RegisterDefaultTranslations(engine, translator)  
    }  

    return  
}

修改後的效果為：

{  
    "code": -1,  
    "msg": {  
        "SingUpForm.Age": "Age必須大於或等於1",  
        "SingUpForm.Email": "Email為必填字段",  
        "SingUpForm.Name": "Name為必填字段",  
        "SingUpForm.Password": "Password為必填字段",  
        "SingUpForm.RePassword": "RePassword為必填字段"  
    }  
}

響應內容結構屬性名稱首字母小寫#

原來的響應內容：

{  
    "code": -1,  
    "msg": {  
        "SingUpForm.Age": "Age必須大於或等於1",  
        "SingUpForm.Email": "Email為必填字段",  
        "SingUpForm.Name": "Name為必填字段",  
        "SingUpForm.Password": "Password為必填字段",  
        "SingUpForm.RePassword": "RePassword為必填字段"  
    }  
}

修改後的內容為：

{  
    "code": -1,  
    "msg": {  
        "SingUpForm.age": "age必須大於或等於1",  
        "SingUpForm.email": "email為必填字段",  
        "SingUpForm.name": "name為必填字段",  
        "SingUpForm.password": "password為必填字段",  
        "SingUpForm.rePassword": "rePassword為必填字段"  
    }  
}

完整代碼為：

package main  

import (  
    "fmt"  
    "net/http"  
    "reflect"  
    "strings"  

    "github.com/gin-gonic/gin"  
    "github.com/gin-gonic/gin/binding"  
    "github.com/go-playground/locales/en"  
    "github.com/go-playground/locales/zh"  
    ut "github.com/go-playground/universal-translator"  
    "github.com/go-playground/validator/v10"  

    en_translations "github.com/go-playground/validator/v10/translations/en"  
    zh_translations "github.com/go-playground/validator/v10/translations/zh"  
)  

// 翻譯校驗信息  
func main() {  
    if err := InitTranslate("zh"); err != nil {  
        fmt.Println("初始化翻譯器出錯")  
        return  
    }  

    r := gin.Default()  

    r.POST("/", func(c *gin.Context) {  
        var singUpForm SingUpForm  
        if err := c.ShouldBind(&singUpForm); nil != err {  
            // 出現錯誤  
            errors, ok := err.(validator.ValidationErrors)  
            if !ok {  
                c.JSON(http.StatusOK, gin.H{  
                    "code": -1,  
                    "msg":  fmt.Errorf("error getting translation of error message, %s", err.Error()),  
                })  
                return  
            }  

            c.JSON(http.StatusBadRequest, gin.H{  
                "code": -1,  
                "msg":  errors.Translate(translator),  
            })  

            return  
        }  

        c.JSON(http.StatusOK, gin.H{  
            "code": 0,  
            "msg":  "登錄成功",  
        })  
    })  

    // 監聽並在 0.0.0.0:8080 上啟動服務  
    r.Run(":8080")  
}  

type SingUpForm struct {  
    Age        uint8  `json:"age" binding:"gte=1,lte=130"`  
    Name       string `json:"name" binding:"required,min=3"`  
    Email      string `json:"email" binding:"required,email"`  
    Password   string `json:"password" binding:"required"`  
    RePassword string `json:"rePassword" binding:"required,eqfield=Password"`  
}  

// use a single instance , it caches struct info  
var (  
    uni        *ut.UniversalTranslator  
    validate   *validator.Validate  
    translator ut.Translator  
)  

func InitTranslate(locale string) (err error) {  
    // 修改 gin 框架中的 validator 引擎屬性，實現翻譯效果  
    engine, ok := binding.Validator.Engine().(*validator.Validate)  
    if !ok {  
        fmt.Println("獲取 gin 框架的 validator 出錯")  
    }  

    // 實現響應內容 tag 首字母小寫  
    engine.RegisterTagNameFunc(func(field reflect.StructField) string {  
        // 如 RePassword string `json:"rePassword" binding:"required,eqfield=Password"`  
        // 那麼 jsonTag 就是 rePassword  
        jsonTag := field.Tag.Get("json")  
        // 分割，例如 strings.SplitN("a,b,c", ",", 2) 那麼就是 [a b,c]，strings.SplitN("a,b,c,d", ",", 2) 那麼就是 [a b c,d]  
        splitN := strings.SplitN(jsonTag, ",", 2)  
        name := splitN[0]  
        if name == "-" {  
            return ""  
        }  
        return name  
    })  

    zhT := zh.New()  
    enT := en.New()  

    uni := ut.New(enT, zhT, enT)  

    translator, ok = uni.GetTranslator(locale)  
    if !ok {  
        return fmt.Errorf("uni.GetTranslator(%s)", locale)  
    }  

    switch locale {  
    case "en":  
        en_translations.RegisterDefaultTranslations(engine, translator)  
    case "zh":  
        zh_translations.RegisterDefaultTranslations(engine, translator)  
    }  

    return  
}  

// 移除響應的 Struct 名稱，例如 `SingUpForm.age` 會變成 `age`  
func removeTopStruct(fields map[string]string) map[string]string {  
    resp := make(map[string]string)  
    for key, value := range fields {  
        resp[key[strings.Index(key, ".")+1:]] = value  
    }  
    return resp  
}

移除響應內容中的構造體#