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golang常用庫：gorilla/mux-http路由庫使用
golang常用庫：配置文件解析庫-viper使用
golang常用庫：操作數(shù)據(jù)庫的orm框架-gorm基本使用
golang常用庫：字段參數(shù)驗證庫-validator使用

一、背景

在平常開發(fā)中，特別是在web應用開發(fā)中，為了驗證輸入字段的合法性，都會做一些驗證操作。比如對用戶提交的表單字段進行驗證，或者對請求的API接口字段進行驗證，驗證字段的合法性，保證輸入字段值的安全，防止用戶的惡意請求。

一般的做法是用正則表達式，一個字段一個字段的進行驗證。一個一個字段驗證的話，寫起來比較繁瑣。那有沒更好的方法，進行字段的合法性驗證？有，這就是下面要介紹的 validator 這個驗證組件。

代碼地址：
https://github.com/go-playground/validator

文檔地址：
https://github.com/go-playground/validator/blob/master/README.md

二、功能介紹

這個驗證包 github.com/go-playground/validator 驗證功能非常多。

標記之間特殊符號說明

逗號( , )：把多個驗證標記隔開。注意：隔開逗號之間不能有空格, validate:"lt=0,gt=100"，逗號那里不能有空格，否則panic
橫線( - )：跳過該字段不驗證
豎線( | )：使用多個驗證標記，但是只需滿足其中一個即可
required：表示該字段值必輸設置，且不能為默認值
omitempty：如果字段未設置，則忽略它

范圍比較驗證

doc: https://github.com/go-playground/validator/blob/master/README.md#comparisons

范圍驗證: 切片、數(shù)組和map、字符串，驗證其長度；數(shù)值，驗證大小范圍

lte：小于等于參數(shù)值，validate:"lte=3" (小于等于3)
gte：大于等于參數(shù)值，validate:"lte=0,gte=120" (大于等于0小于等于120)
lt：小于參數(shù)值，validate:"lt=3" (小于3)
gt：大于參數(shù)值，validate:"lt=0,gt=120" (大于0小于120)
len：等于參數(shù)值，validate:"len=2"
max：大于等于參數(shù)值，validate:"max=2" (大于等于2)
min：小于等于參數(shù)值，validate:"min=2,max=10" (大于等于2小于等于10)
ne：不等于，validate:"ne=2" (不等于2)
oneof：只能是列舉出的值其中一個，這些值必須是數(shù)值或字符串，以空格分隔，如果字符串中有空格，將字符串用單引號包圍，validate:"oneof=red green"

例子：

type User struct {
 Name string `json:"name" validate:"min=0,max=35"`
 Age unit8 `json:"age" validate:"lte=0,gte=90"`
}

更多功能請參看文檔 validator comparisons doc

字符串驗證

doc: https://github.com/go-playground/validator/blob/master/README.md#strings

contains：包含參數(shù)子串，validate:"contains=tom" (字段的字符串值包含tom)
excludes：包含參數(shù)子串，validate:"excludes=tom" (字段的字符串值不包含tom)
startswith：以參數(shù)子串為前綴，validate:"startswith=golang"
endswith：以參數(shù)子串為后綴，validate:"startswith=world"

例子：

type User struct { 
 Name string `validate:"contains=tom"` 
 Age int `validate:"min=1"`
}

更多功能請參看文檔 validator strings doc

字段驗證

doc: https://github.com/go-playground/validator/blob/master/README.md#fields

eqcsfield：跨不同結(jié)構(gòu)體字段驗證，比如說 Struct1 Filed1，與結(jié)構(gòu)體Struct2 Field2相等，

type Struct1 struct {
 Field1 string `validate:eqcsfield=Struct2.Field2`
 Struct2 struct {
 Field2 string 
 }
}

necsfield：跨不同結(jié)構(gòu)體字段不相等
eqfield：同一結(jié)構(gòu)體字段驗證相等，最常見的就是輸入2次密碼驗證

type User struct { 
 Name string `validate:"lte=4"` 
 Age int `validate:"min=20"` 
 Password string `validate:"min=10"`
 Password2 string `validate:"eqfield=Password"`
}

nefield：同一結(jié)構(gòu)體字段驗證不相等

type User struct {
 Name string `validate:"lte=4"` 
 Age int `validate:"min=20"` 
 Password string `validate:"min=10,nefield=Name"`
}

gtefield：大于等于同一結(jié)構(gòu)體字段，validate:"gtefiled=Field2"
ltefield：小于等于同一結(jié)構(gòu)體字段

更多功能請參看文檔：validator Fields DOC

網(wǎng)絡驗證

doc: https://github.com/go-playground/validator/blob/master/README.md#network

ip：字段值是否包含有效的IP地址，validate:"ip"
ipv4：字段值是否包含有效的ipv4地址，validate:"ipv4"
ipv6：字段值是否包含有效的ipv6地址，validate:"ipv6"
uri：字段值是否包含有效的uri，validate:"uri"
url：字段值是否包含有效的uri，validate:"url"

更多功能請參看文檔：validator network DOC

Format

doc: https://github.com/go-playground/validator/blob/master/README.md#format

base64：字段值是否包含有效的base64值

更多功能請參看文檔 validator strings doc

其他

請參看文檔: https://github.com/go-playground/validator/blob/master/README.md#other

三、安裝

go get:

go get github.com/go-playground/validator/v10

在文件中引用validator包：

import "github.com/go-playground/validator/v10"

四、validator使用

文檔：https://github.com/go-playground/validator/blob/master/README.md#examples

例子1：驗證單個字段變量值

validation1.go

package main

import (
	"fmt"

	"github.com/go-playground/validator/v10"
)

func main() {
	validate := validator.New()

	var boolTest bool
	err := validate.Var(boolTest, "required")
	if err != nil {
		fmt.Println(err)
	}
	var stringTest string = ""
	err = validate.Var(stringTest, "required")
	if err != nil {
		fmt.Println(err)
	}

	var emailTest string = "test@126.com"
	err = validate.Var(emailTest, "email")
	if err != nil {
		fmt.Println(err)
	} else {
		fmt.Println("success") // 輸出： success。 說明驗證成功
	}

	emailTest2 := "test.126.com"
	errs := validate.Var(emailTest2, "required,email")
	if errs != nil {
		fmt.Println(errs) // 輸出: Key: "" Error:Field validation for "" failed on the "email" tag。驗證失敗
	}

	fmt.Println("\r\nEnd!!")
 
}

運行輸出：

go run simple1.go
Key: '' Error:Field validation for '' failed on the 'required' tag
Key: '' Error:Field validation for '' failed on the 'required' tag
success
Key: '' Error:Field validation for '' failed on the 'email' tag

End!!

例子2：驗證結(jié)構(gòu)體struct

from：struct validate

validation_struct.go，這個程序還列出了效驗出錯字段的一些信息，

package main

import (
	"fmt"

	"github.com/go-playground/validator/v10"
)

type User struct {
	FirstName string `validate:"required"`
	LastName string `validate:"required"`
	Age uint8 `validate:"gte=0,lte=130"`
	Email string `validate:"required,email"`
	Addresses []*Address `validate:"required,dive,required"`
}

type Address struct {
	Street string `validate:"required"`
	City string `validate:"required"`
	Planet string `validate:"required"`
	Phone string `validate:"required"`
}

func main() {
	address := Address{
		Street: "Eavesdown Docks",
		Planet: "Persphone",
		Phone: "none",
	}

	user := User{
		FirstName: "Badger",
		LastName: "Smith",
		Age: 135,
		Email: "Badger.Smith@gmail.com",
		Addresses: []*Address{address},
	}

	validate := validator.New()
	err := validate.Struct(user)
	if err != nil {
		fmt.Println("=== error msg ====")
		fmt.Println(err)

		if _, ok := err.(*validator.InvalidValidationError); ok {
			fmt.Println(err)
			return
		}

		fmt.Println("\r\n=========== error field info ====================")
		for _, err := range err.(validator.ValidationErrors) {
 // 列出效驗出錯字段的信息
			fmt.Println("Namespace: ", err.Namespace())
			fmt.Println("Fild: ", err.Field())
			fmt.Println("StructNamespace: ", err.StructNamespace())
			fmt.Println("StructField: ", err.StructField())
			fmt.Println("Tag: ", err.Tag())
			fmt.Println("ActualTag: ", err.ActualTag())
			fmt.Println("Kind: ", err.Kind())
			fmt.Println("Type: ", err.Type())
			fmt.Println("Value: ", err.Value())
			fmt.Println("Param: ", err.Param())
			fmt.Println()
		}

		// from here you can create your own error messages in whatever language you wish
		return
	}
}

運行輸出：

$ go run validation_struct.go
=== error msg ====
Key: 'User.Age' Error:Field validation for 'Age' failed on the 'lte' tag
Key: 'User.Addresses[0].City' Error:Field validation for 'City' failed on the 'required' tag

=========== error field info ====================
Namespace: User.Age
Fild: Age
StructNamespace: User.Age
StructField: Age
Tag: lte
ActualTag: lte
Kind: uint8
Type: uint8
Value: 135
Param: 130

Namespace: User.Addresses[0].City
Fild: City
StructNamespace: User.Addresses[0].City
StructField: City
Tag: required
ActualTag: required
Kind: string
Type: string
Value:
Param:

還可以給字段加一些其他tag信息，方面form，json的解析，如下：

type User struct {
 FirstName string `form:"firstname" json:"firstname" validate:"required"`
	LastName string `form:"lastname" json:"lastname" validate:"required"`
	Age uint8 ` form:"age" json:"age"validate:"gte=0,lte=130"`
	Email string ` form:"email" json:"email" validate:"required,email"`
}

用戶自定義函數(shù)驗證

用戶自定義函數(shù)驗證字段是否合法，效驗是否正確。

例子3: 通過字段tag自定義函數(shù)

validate.RegisterValidation

customer_tag.go：

package main

import (
	"fmt"

	"github.com/go-playground/validator/v10"
)

type User struct {
	Name string `form:"name" json:"name" validate:"required,CustomerValidation"` //注意：required和CustomerValidation之間不能有空格，否則panic。CustomerValidation：自定義tag-函數(shù)標簽
	Age uint8 ` form:"age" json:"age" validate:"gte=0,lte=80"` //注意：gte=0和lte=80之間不能有空格，否則panic
}

var validate *validator.Validate

func main() {
	validate = validator.New()
	validate.RegisterValidation("CustomerValidation", CustomerValidationFunc) //注冊自定義函數(shù)，前一個參數(shù)是struct里tag自定義，后一個參數(shù)是自定義的函數(shù)

	user := User{
		Name: "jimmy",
		Age: 86,
	}

	fmt.Println("first value: ", user)
	err := validate.Struct(user)
	if err != nil {
		fmt.Printf("Err(s):\n%+v\n", err)
	}

	user.Name = "tom"
	user.Age = 29
	fmt.Println("second value: ", user)
	err = validate.Struct(user)
	if err != nil {
		fmt.Printf("Err(s):\n%+v\n", err)
	}
}

// 自定義函數(shù)
func CustomerValidationFunc(f1 validator.FieldLevel) bool {
 // f1 包含了字段相關信息
 // f1.Field() 獲取當前字段信息
 // f1.Param() 獲取tag對應的參數(shù)
 // f1.FieldName() 獲取字段名稱
 
	return f1.Field().String() == "jimmy"
}

運行輸出：

$ go run customer.go
first value: {jimmy 86}
Err(s):
Key: 'User.Age' Error:Field validation for 'Age' failed on the 'lte' tag
second value: {tom 29}
Err(s):
Key: 'User.Name' Error:Field validation for 'Name' failed on the 'CustomerValidation' tag

**注意：

上面代碼user struct定義中，validate里的required和CustomerValidation之間不能有空格，否則運行時報panic錯誤：panic: Undefined validation function ' CustomerValidation' on field 'Name'

例子4：自定義函數(shù)-直接注冊函數(shù)1

不通過字段tag自定義函數(shù)，直接注冊函數(shù)。

RegisterStructValidation

https://github.com/go-playground/validator/blob/master/_examples/struct-level/main.go

customer1.go

package main

import (
	"fmt"

	"github.com/go-playground/validator/v10"
)

type User struct {
	FirstName string `json:firstname`
	LastName string `json:lastname`
	Age uint8 `validate:"gte=0,lte=130"`
	Email string `validate:"required,email"`
	FavouriteColor string `validate:"hexcolor|rgb|rgba"`
}

var validate *validator.Validate

func main() {
	validate = validator.New()

	validate.RegisterStructValidation(UserStructLevelValidation, User{})

	user := User{
		FirstName: "",
		LastName: "",
		Age: 30,
		Email: "TestFunc@126.com",
		FavouriteColor: "#000",
	}

	err := validate.Struct(user)
	if err != nil {
		fmt.Println(err)
	}
}

func UserStructLevelValidation(sl validator.StructLevel) {
	user := sl.Current().Interface().(User)

	if len(user.FirstName) == 0  len(user.LastName) == 0 {
		sl.ReportError(user.FirstName, "FirstName", "firstname", "firstname", "")
		sl.ReportError(user.LastName, "LastName", "lastname", "lastname", "")
	}
}

運行輸出：

$ go run customer1.go
Key: 'User.FirstName' Error:Field validation for 'FirstName' failed on the 'firstname' tag
Key: 'User.LastName' Error:Field validation for 'LastName' failed on the 'lastname' tag

例子5：自定義函數(shù)-直接注冊函數(shù)2

RegisterCustomTypeFunc

https://github.com/go-playground/validator/blob/master/_examples/custom/main.go

validate.RegisterCustomTypeFunc：驗證類型的自定義函數(shù)

customer2.go：

package main

import (
	"database/sql"
	"database/sql/driver"
	"fmt"
	"reflect"

	"github.com/go-playground/validator/v10"
)

type DbBackedUser struct {
	Name sql.NullString `validate:"required"`
	Age sql.NullInt64 `validate:"required"`
}

var validate *validator.Validate

func main() {
	validate = validator.New()

	validate.RegisterCustomTypeFunc(ValidateValuer, sql.NullString{}, sql.NullInt64{}, sql.NullBool{}, sql.NullFloat64{})

	// build object for validation
	x := DbBackedUser{Name: sql.NullString{String: "", Valid: true}, Age: sql.NullInt64{Int64: 0, Valid: false}}

	err := validate.Struct(x)
	if err != nil {
		fmt.Printf("Err(s):\n%+v\n", err)
	}
}

func ValidateValuer(field reflect.Value) interface{} {
	if valuer, ok := field.Interface().(driver.Valuer); ok {
		val, err := valuer.Value()
		if err == nil {
			return val
		}
		// handle the error how you want
	}
	return nil
}

運行輸出：

$ go run customer.go
Err(s):
Key: 'DbBackedUser.Name' Error:Field validation for 'Name' failed on the 'required' tag
Key: 'DbBackedUser.Age' Error:Field validation for 'Age' failed on the 'required' tag

注意，這個函數(shù)：
RegisterCustomTypeFunc，它上面有2行注釋：

// RegisterCustomTypeFunc registers a CustomTypeFunc against a number of types
//
// NOTE: this method is not thread-safe it is intended that these all be registered prior to any validation

它是一個驗證數(shù)據(jù)類型自定義函數(shù)，NOTE:這個方法不是線程安全的

五、參考

https://github.com/go-playground/validator/blob/master/README.mdhttps://github.com/go-playground/validator/tree/master/_examples

總結(jié)

到此這篇關于golang常用庫：字段參數(shù)驗證庫-validator使用的文章就介紹到這了,更多相關golang字段參數(shù)驗證庫validator內(nèi)容請搜索腳本之家以前的文章或繼續(xù)瀏覽下面的相關文章希望大家以后多多支持腳本之家！

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