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golang 如何验证struct字段的数据格式(二)
2017-12-14 14:31:36 】 浏览:1227
Tags:golang 如何 验证 struct 段的 数据 格式

) } return true, nil } type NumberValidator struct { Min int Max int } func (v NumberValidator) Validate(val interface{}) (bool, error) { num := val.(int) if num < v.Min { return false, fmt.Errorf("should be greater than %v", v.Min) } if v.Max >= v.Min && num > v.Max { return false, fmt.Errorf("should be less than %v", v.Max) } return true, nil } type EmailValidator struct { } func (v EmailValidator) Validate(val interface{}) (bool, error) { if !mailRe.MatchString(val.(string)) { return false, fmt.Errorf("is not a valid email address") } return true, nil } func getValidatorFromTag(tag string) Validator { args := strings.Split(tag, ",") switch args[0] { case "number": validator := NumberValidator{} //将structTag中的min和max解析到结构体中 fmt.Sscanf(strings.Join(args[1:], ","), "min=%d,max=%d", &validator.Min, &validator.Max) return validator case "string": validator := StringValidator{} fmt.Sscanf(strings.Join(args[1:], ","), "min=%d,max=%d", &validator.Min, &validator.Max) return validator case "email": return EmailValidator{} } return DefaultValidator{} } func validateStruct(s interface{}) []error { errs := []error{} v := reflect.ValueOf(s) for i := 0; i < v.NumField(); i++ { //利用反射获取structTag tag := v.Type().Field(i).Tag.Get(tagName) if tag == "" || tag == "-" { continue } validator := getValidatorFromTag(tag) valid, err := validator.Validate(v.Field(i).Interface()) if !valid && err != nil { errs = append(errs, fmt.Errorf("%s %s", v.Type().Field(i).Name, err.Error())) } } return errs } type User struct { Id int `validate:"number,min=1,max=1000"` Name string `validate:"string,min=2,max=10"` Bio string `validate:"string"` Email string `validate:"email"` } func main() { user := User{ Id: 0, Name: "superlongstring", Bio: "", Email: "foobar", } fmt.Println("Errors:") for i, err := range validateStruct(user) { fmt.Printf("\t%d. %s\n", i+1, err.Error()) } }

代码很好理解,结构也很清晰,不做过多解释了^_^

github上其实已经有现成的验证包了govalidator,支持内置支持的验证tag和自定义验证tag:

package main

import (
    "github.com/asaskevich/govalidator"
    "fmt"
    "strings"
)

type Server struct {
    ID         string `valid:"uuid,required"`
    Name       string `valid:"machine_id"`
    HostIP     string `valid:"ip"`
    MacAddress string `valid:"mac,required"`
    WebAddress string `valid:"url"`
    AdminEmail string `valid:"email"`
}

func main() {
    server := &Server{
        ID:         "123e4567-e89b-12d3-a456-426655440000",
        Name:       "IX01",
        HostIP:     "127.0.0.1",
        MacAddress: "01:23:45:67:89:ab",
        WebAddress: "www.example.com",
        AdminEmail: "admin@exmaple.com",
    }

    //自定义tag验证函数
    govalidator.TagMap["machine_id"] = govalidator.Validator(func(str string) bool {
        return strings.HasPrefix(str, "IX")
    })

    if ok, err := govalidator.ValidateStruct(server); err != nil {
        panic(err)
    } else {
        fmt.Printf("OK: %v\n", ok)
    }
}

参考资料:

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