golang常用库：gorilla/mux-http路由库使用
golang常用库：配置文件解析库-viper使用
golang常用库：操作数据库的orm框架-gorm基本使用
golang常用库：字段参数验证库-validator使用
一、背景
在平常开发中，特别是在web应用开发中，为了验证输入字段的合法性，都会做一些验证操作。比如对用户提交的表单字段进行验证，或者对请求的API接口字段进行验证，验证字段的合法性，保证输入字段值的安全，防止用户的恶意请求。
一般的做法是用正则表达式，一个字段一个字段的进行验证。一个一个字段验证的话，写起来比较繁琐。那有没更好的方法，进行字段的合法性验证？有， 这就是下面要介绍的 validator 这个验证组件。
代码地址：
https://github.com/go-playground/validator
文档地址：
https://github.com/go-playground/validator/blob/master/README.md
二、功能介绍
这个验证包 github.com/go-playground/validator 验证功能非常多。
标记之间特殊符号说明
- 逗号(
,)：把多个验证标记隔开。注意：隔开逗号之间不能有空格,validate:"lt=0,gt=100"，逗号那里不能有空格，否则panic - 横线(
-)：跳过该字段不验证 - 竖线(
|)：使用多个验证标记，但是只需满足其中一个即可 - required：表示该字段值必输设置，且不能为默认值
- omitempty：如果字段未设置，则忽略它
范围比较验证
doc: https://github.com/go-playground/validator/blob/master/README.md#comparisons
范围验证: 切片、数组和map、字符串，验证其长度；数值，验证大小范围
- lte：小于等于参数值，
validate:"lte=3"(小于等于3) - gte：大于等于参数值，
validate:"lte=0,gte=120"(大于等于0小于等于120) - lt：小于参数值，
validate:"lt=3"(小于3) - gt：大于参数值，
validate:"lt=0,gt=120"(大于0小于120) - len：等于参数值，
validate:"len=2" - max：大于等于参数值，
validate:"max=2"(大于等于2) - min：小于等于参数值，
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：只能是列举出的值其中一个，这些值必须是数值或字符串，以空格分隔，如果字符串中有空格，将字符串用单引号包围，
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"`
}
更多功能请参看文档 validator comparisons doc
字符串验证
doc: https://github.com/go-playground/validator/blob/master/README.md#strings
- contains：包含参数子串，
validate:"contains=tom"(字段的字符串值包含tom) - excludes：包含参数子串，
validate:"excludes=tom"(字段的字符串值不包含tom) - startswith：以参数子串为前缀，
validate:"startswith=golang" - endswith：以参数子串为后缀，
validate:"startswith=world"
例子：
type User struct {
Name string `validate:"contains=tom"`
Age int `validate:"min=1"`
}
更多功能请参看文档 validator strings doc
字段验证
doc: https://github.com/go-playground/validator/blob/master/README.md#fields
eqcsfield：跨不同结构体字段验证，比如说 Struct1 Filed1，与结构体Struct2 Field2相等，
type Struct1 struct {
Field1 string `validate:eqcsfield=Struct2.Field2`
Struct2 struct {
Field2 string
}
}
- necsfield：跨不同结构体字段不相等
- eqfield：同一结构体字段验证相等，最常见的就是输入2次密码验证
type User struct {
Name string `validate:"lte=4"`
Age int `validate:"min=20"`
Password string `validate:"min=10"`
Password2 string `validate:"eqfield=Password"`
}
nefield：同一结构体字段验证不相等
type User struct {
Name string `validate:"lte=4"`
Age int `validate:"min=20"`
Password string `validate:"min=10,nefield=Name"`
}
- gtefield：大于等于同一结构体字段，
validate:"gtefiled=Field2" - ltefield：小于等于同一结构体字段
更多功能请参看文档：validator Fields DOC
网络验证
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"
更多功能请参看文档：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
更多功能请参看文档 validator strings doc
其他
请参看文档: https://github.com/go-playground/validator/blob/master/README.md#other
三、安装
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
文档：https://github.com/go-playground/validator/blob/master/README.md#examples
例子1：验证单个字段变量值
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 = "[email protected]"
err = validate.Var(emailTest, "email")
if err != nil {
fmt.Println(err)
} else {
fmt.Println("success") // 输出： success。 说明验证成功
}
emailTest2 := "test.126.com"
errs := validate.Var(emailTest2, "required,email")
if errs != nil {
fmt.Println(errs) // 输出: Key: "" Error:Field validation for "" failed on the "email" tag。验证失败
}
fmt.Println("\r\nEnd!!")
}
运行输出：
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' tagEnd!!
例子2：验证结构体struct
from：struct validate
validation_struct.go，这个程序还列出了效验出错字段的一些信息，
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: "[email protected]",
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) {
// 列出效验出错字段的信息
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
}
}
运行 输出：
$ 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: 130Namespace: User.Addresses[0].City
Fild: City
StructNamespace: User.Addresses[0].City
StructField: City
Tag: required
ActualTag: required
Kind: string
Type: string
Value:
Param:
还可以给字段加一些其他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"`
}
用户自定义函数验证
用户自定义函数验证字段是否合法，效验是否正确。
例子3: 通过字段tag自定义函数
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之间不能有空格，否则panic。CustomerValidation：自定义tag-函数标签
Age uint8 ` form:"age" json:"age" validate:"gte=0,lte=80"` //注意：gte=0和lte=80之间不能有空格，否则panic
}
var validate *validator.Validate
func main() {
validate = validator.New()
validate.RegisterValidation("CustomerValidation", CustomerValidationFunc) //注册自定义函数，前一个参数是struct里tag自定义，后一个参数是自定义的函数
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)
}
}
// 自定义函数
func CustomerValidationFunc(f1 validator.FieldLevel) bool {
// f1 包含了字段相关信息
// f1.Field() 获取当前字段信息
// f1.Param() 获取tag对应的参数
// f1.FieldName() 获取字段名称
return f1.Field().String() == "jimmy"
}
运行输出：
$ 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：
上面代码user struct定义中 ，validate里的required和CustomerValidation之间不能有空格，否则运行时报panic错误：panic: Undefined validation function ' CustomerValidation' on field 'Name'
例子4：自定义函数-直接注册函数1
不通过字段tag自定义函数，直接注册函数。
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: "[email protected]",
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", "")
}
}
运行输出：
$ 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：自定义函数-直接注册函数2
RegisterCustomTypeFunc
https://github.com/go-playground/validator/blob/master/_examples/custom/main.go
validate.RegisterCustomTypeFunc：验证类型的自定义函数
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
}
运行输出：
$ 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，这个函数：
RegisterCustomTypeFunc，它上面有2行注释：
// 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
它是一个验证数据类型自定义函数，NOTE:这个方法不是线程安全的
五、参考
https://github.com/go-playground/validator/blob/master/README.mdhttps://github.com/go-playground/validator/tree/master/_examples
总结
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