前言
在web應用中經常會遇到數據驗證問題,普通的驗證方法比較繁瑣,這裏介紹一個使用比較多的包validator。
原理
將驗證規則寫在struct對字段tag裏,再通過反射(reflect)獲取struct的tag,實現數據驗證。
安裝
go get github.com/go-playground/validator/v10
示例
package main
import (
"fmt"
"github.com/go-playground/validator/v10"
)
type Users struct {
Phone string `form:"phone" json:"phone" validate:"required"`
Passwd string `form:"passwd" json:"passwd" validate:"required,max=20,min=6"`
Code string `form:"code" json:"code" validate:"required,len=6"`
}
func main() {
users := &Users{
Phone: "1326654487",
Passwd: "123",
Code: "123456",
}
validate := validator.New()
err := validate.Struct(users)
if err != nil {
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err)//Key: 'Users.Passwd' Error:Field validation for 'Passwd' failed on the 'min' tag
return
}
}
return
}
驗證規則
- required :必填
- email:驗證字符串是email格式;例:“email”
- url:這將驗證字符串值包含有效的網址;例:“url”
- max:字符串最大長度;例:“max=20”
- min:字符串最小長度;例:“min=6”
- excludesall:不能包含特殊字符;例:“excludesall=0x2C”//注意這裏用十六進制表示。
- len:字符長度必須等於n,或者數組、切片、map的len值爲n,即包含的項目數;例:“len=6”
- eq:數字等於n,或者或者數組、切片、map的len值爲n,即包含的項目數;例:“eq=6”
- ne:數字不等於n,或者或者數組、切片、map的len值不等於爲n,即包含的項目數不爲n,其和eq相反;例:“ne=6”
- gt:數字大於n,或者或者數組、切片、map的len值大於n,即包含的項目數大於n;例:“gt=6”
- gte:數字大於或等於n,或者或者數組、切片、map的len值大於或等於n,即包含的項目數大於或等於n;例:“gte=6”
- lt:數字小於n,或者或者數組、切片、map的len值小於n,即包含的項目數小於n;例:“lt=6”
- lte:數字小於或等於n,或者或者數組、切片、map的len值小於或等於n,即包含的項目數小於或等於n;例:“lte=6”
跨字段驗證
如想實現比較輸入密碼和確認密碼是否一致等類似場景
eqfield=Field
: 必須等於 Field 的值;nefield=Field
: 必須不等於 Field 的值;gtfield=Field
: 必須大於 Field 的值;gtefield=Field
: 必須大於等於 Field 的值;ltfield=Field
: 必須小於 Field 的值;ltefield=Field
: 必須小於等於 Field 的值;eqcsfield=Other.Field
: 必須等於 struct Other 中 Field 的值;necsfield=Other.Field
: 必須不等於 struct Other 中 Field 的值;gtcsfield=Other.Field
: 必須大於 struct Other 中 Field 的值;gtecsfield=Other.Field
: 必須大於等於 struct Other 中 Field 的值;ltcsfield=Other.Field
: 必須小於 struct Other 中 Field 的值;ltecsfield=Other.Field
: 必須小於等於 struct Other 中 Field 的值;
示例
type UserReg struct {
Passwd string `form:"passwd" json:"passwd" validate:"required,max=20,min=6"`
Repasswd string `form:"repasswd" json:"repasswd" validate:"required,max=20,min=6,eqfield=Passwd"`
}
示例驗證了Passwd,和Repasswd值是否相等。如想了解更多類型,請參考文檔 https://godoc.org/gopkg.in/go-playground/validator.v10
自定義驗證類型
示例:
package main
import (
"fmt"
"github.com/go-playground/validator/v10"
)
type Users struct {
Name string `form:"name" json:"name" validate:"required,CustomValidationErrors"`//包含自定義函數
Age uint8 `form:"age" json:"age" validate:"required,gt=18"`
Passwd string `form:"passwd" json:"passwd" validate:"required,max=20,min=6"`
Code string `form:"code" json:"code" validate:"required,len=6"`
}
func main() {
users := &Users{
Name: "admin",
Age: 12,
Passwd: "123",
Code: "123456",
}
validate := validator.New()
//註冊自定義函數
_=validate.RegisterValidation("CustomValidationErrors", CustomValidationErrors)
err := validate.Struct(users)
if err != nil {
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err)//Key: 'Users.Name' Error:Field validation for 'Name' failed on the 'CustomValidationErrors' tag
return
}
}
return
}
func CustomValidationErrors(fl validator.FieldLevel) bool {
return fl.Field().String() != "admin"
}
翻譯錯誤信息爲中文
通過以上示例我們看到,validator默認的錯誤提示信息類似如下
Key: 'Users.Name' Error:Field validation for 'Name' failed on the 'CustomValidationErrors' tag
顯然這並不是我們想要,如想翻譯成中文,或其他語言怎麼辦?go-playground上提供了很好的解決方法。
先自行安裝需要的兩個包
https://github.com/go-playground/locales
https://github.com/go-playground/universal-translator
執行:
go get github.com/go-playground/universal-translator
go get github.com/go-playground/locales
示例:
package main
import (
"fmt"
"github.com/go-playground/locales/zh"
ut "github.com/go-playground/universal-translator"
"github.com/go-playground/validator/v10"
zh_translations "github.com/go-playground/validator/v10/translations/zh"
)
type Users struct {
Name string `form:"name" json:"name" validate:"required"`
Age uint8 `form:"age" json:"age" validate:"required,gt=18"`
Passwd string `form:"passwd" json:"passwd" validate:"required,max=20,min=6"`
Code string `form:"code" json:"code" validate:"required,len=6"`
}
func main() {
users := &Users{
Name: "admin",
Age: 12,
Passwd: "123",
Code: "123456",
}
uni := ut.New(zh.New())
trans, _ := uni.GetTranslator("zh")
validate := validator.New()
//驗證器註冊翻譯器
err := zh_translations.RegisterDefaultTranslations(validate, trans)
if err!=nil {
fmt.Println(err)
}
err = validate.Struct(users)
if err != nil {
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err.Translate(trans))//Age必須大於18
return
}
}
return
}
輸出:
Age必須大於18
至此我們發現大部分錯誤信息已經翻譯成中文,但字段名(Age)還是沒有翻譯,爲了將字段名翻譯成中文,查了一些資料,https://www.jianshu.com/p/51b9cd2006a8>,
照着做沒有成功(可能有遺漏吧),最後還是翻看了一下源代碼,在<https://github.com/go-playground/validator/blob/master/validator_instance.go,第137行
// RegisterTagNameFunc registers a function to get alternate names for StructFields.
//
// eg. to use the names which have been specified for JSON representations of structs, rather than normal Go field names:
//
// validate.RegisterTagNameFunc(func(fld reflect.StructField) string {
// name := strings.SplitN(fld.Tag.Get("json"), ",", 2)[0]
// if name == "-" {
// return ""
// }
// return name
// })
其實原理就是註冊一個函數,將struct tag裏添加的中文名 作爲備用名。
package main
import (
"fmt"
"github.com/go-playground/locales/zh"
ut "github.com/go-playground/universal-translator"
"github.com/go-playground/validator/v10"
zh_translations "github.com/go-playground/validator/v10/translations/zh"
"reflect"
)
type Users struct {
Name string `form:"name" json:"name" validate:"required" label:"用戶名"`
Age uint8 `form:"age" json:"age" validate:"required,gt=18" label:"年齡"`
Passwd string `form:"passwd" json:"passwd" validate:"required,max=20,min=6"`
Code string `form:"code" json:"code" validate:"required,len=6"`
}
func main() {
users := &Users{
Name: "admin",
Age: 12,
Passwd: "123",
Code: "123456",
}
uni := ut.New(zh.New())
trans, _ := uni.GetTranslator("zh")
validate := validator.New()
//註冊一個函數,獲取struct tag裏自定義的label作爲字段名
validate.RegisterTagNameFunc(func(fld reflect.StructField) string {
name:=fld.Tag.Get("label")
return name
})
//註冊翻譯器
err := zh_translations.RegisterDefaultTranslations(validate, trans)
if err!=nil {
fmt.Println(err)
}
err = validate.Struct(users)
if err != nil {
for _, err := range err.(validator.ValidationErrors) {
fmt.Println(err.Translate(trans))//年齡必須大於18
return
}
}
return
}
輸出結果:
年齡必須大於18
gin 內置的validator
gin已經支持go-playground / validator / v10進行驗證。在此處查看有關標籤用法的完整文檔。
以下只提供了一個綁定ShouldBindWith示例,如需瞭解更多方法,進入這裏。
示例
package main
import (
"fmt"
"github.com/go-playground/locales/zh"
ut "github.com/go-playground/universal-translator"
"github.com/go-playground/validator/v10"
"net/http"
"reflect"
"strings"
"time"
"github.com/gin-gonic/gin"
"github.com/gin-gonic/gin/binding"
zh_translations "github.com/go-playground/validator/v10/translations/zh"
)
var trans ut.Translator
// Booking contains binded and validated data.
type Booking struct {
CheckIn time.Time `form:"check_in" json:"check_in" binding:"required,bookabledate" time_format:"2006-01-02" label:"輸入時間"`
CheckOut time.Time `form:"check_out" json:"check_out" binding:"required,gtfield=CheckIn" time_format:"2006-01-02" label:"輸出時間"`
}
var bookableDate validator.Func = func(fl validator.FieldLevel) bool {
date, ok := fl.Field().Interface().(time.Time)
if ok {
today := time.Now()
if today.After(date) {
return false
}
}
return true
}
func main() {
route := gin.Default()
uni := ut.New(zh.New())
trans, _ = uni.GetTranslator("zh")
if v, ok := binding.Validator.Engine().(*validator.Validate); ok {
//註冊翻譯器
_= zh_translations.RegisterDefaultTranslations(v, trans)
//註冊自定義函數
_=v.RegisterValidation("bookabledate", bookableDate)
//註冊一個函數,獲取struct tag裏自定義的label作爲字段名
v.RegisterTagNameFunc(func(fld reflect.StructField) string {
name:=fld.Tag.Get("label")
return name
})
//根據提供的標記註冊翻譯
v.RegisterTranslation("bookabledate", trans, func(ut ut.Translator) error {
return ut.Add("bookabledate", "{0}不能早於當前時間或{1}格式錯誤!", true)
}, func(ut ut.Translator, fe validator.FieldError) string {
t, _ := ut.T("bookabledate", fe.Field(), fe.Field())
return t
})
}
route.GET("/bookable", getBookable)
route.Run(":8085")
}
func getBookable(c *gin.Context) {
var b Booking
if err := c.ShouldBindWith(&b, binding.Query); err == nil {
c.JSON(http.StatusOK, gin.H{"message": "Booking dates are valid!"})
} else {
errs := err.(validator.ValidationErrors)
fmt.Println(errs.Translate(trans))
//for _, e := range errs {
// // can translate each error one at a time.
// fmt.Println(e.Translate(trans))
//}
c.JSON(http.StatusBadRequest, gin.H{"error": errs.Translate(trans)})
}
}
運行程序,執行以下命令
$ curl "localhost:8085/bookable?check_in=2018-04-16&check_out=2018-04-16"
結果:
{"error":{"Booking.輸入時間":"輸入時間不能早於當前時間或輸入時間格式錯誤!","Booking.輸出時間":"輸出時間必須大於CheckIn"}}
查看以上結果我們發現翻譯還是不太完美,如規則中有gtfield的情況,字段(CheckIn)並沒有被翻譯。所以通過struct添加label的方式並不能從根本上解決字段翻譯問題。爲了得到想要的結果,就需要將錯誤信息做單獨處理再輸出。
先定義翻譯庫
var BookingTrans =map[string]string{"CheckIn":"輸入時間","CheckOut":"輸出時間"}
再定義翻譯函數
func TransTagName(libTans,err interface{}) interface{} {
switch err.(type) {
case validator.ValidationErrorsTranslations:
var errs map[string]string
errs = make(map[string]string,0)
for k,v:=range err.(validator.ValidationErrorsTranslations){
for key,value:=range libTans.(map[string]string) {
v=strings.Replace(v,key,value,-1)
}
errs[k] = v
}
return errs
case string:
var errs string
for key,value:=range libTans.(map[string]string) {
errs=strings.Replace(errs,key,value,-1)
}
return errs
default:
return err
}
}
將原來翻譯錯誤信息的地方
errs.Translate(trans)
修改爲
msg:=TransTagName(BookingTrans,errs.Translate(trans))
fmt.Println(msg)
結果
{"error":{"Booking.輸入時間":"輸入時間不能早於當前時間或輸入時間格式錯誤!","Booking.輸出時間":"輸出時間必須大於輸入時間"}}
小結:
參考:
https://github.com/go-playground/validator
https://github.com/gin-gonic/gin
https://gitissue.com/issues/5d06a73965d56f73569b825f
https://segmentfault.com/a/1190000022527284