Golang go-playground/validator：如何在oneof规则中包含单引号

我在使用Golang的go-playground/validator/v10包验证结构体字段时，尝试通过oneof标签验证字段值是否匹配包含单引号的预定义值，但带单引号的预期有效值始终验证失败。

原代码 #

package main

import (
    "fmt"

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

// Struct with validation tag
type Award struct {
    Title string `validate:"oneof=palm'dor level'dor 'state award'"`
}

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

    // Test cases
    testCases := []Award{
        {"palm'dor"},    // Expected: Valid
        {"level'dor"},   // Expected: Valid
        {"state award"}, // Expected: Valid
        {"other"},       // Expected: Invalid
    }

    for _, testCase := range testCases {
        err := validate.Struct(testCase)
        if err != nil {
            fmt.Printf("Input: %q - Invalid (%v)\n", testCase.Title, err)
        } else {
            fmt.Printf("Input: %q - Valid\n", testCase.Title)
        }
    }
}

预期行为 #

程序应将"palm'dor"、"level'dor"和"state award"判定为有效输入，其他值标记为无效。

实际输出 #

Input: "palm'dor" - Invalid (Key: 'Award.Title' Error:Field validation for 'Title' failed on the 'oneof' tag)
Input: "level'dor" - Invalid (Key: 'Award.Title' Error:Field validation for 'Title' failed on the 'oneof' tag)
Input: "state award" - Valid
Input: "other" - Invalid (Key: 'Award.Title' Error:Field validation for 'Title' failed on the 'oneof' tag)

问题原因 #

validator的oneof标签默认用空格分隔选项，单引号的作用是包裹包含空格的选项（比如'state award'）。但如果选项本身包含单引号，直接书写会被解析器错误识别，导致选项匹配失败。

解决方法 #

当选项中包含单引号时，需要用两个单引号进行转义；如果选项不含空格，不需要额外用单引号包裹。修改后的oneof标签格式如下：

Title string `validate:"oneof=palm''dor level''dor 'state award'"`

修改后的完整代码 #

package main

import (
    "fmt"

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

type Award struct {
    Title string `validate:"oneof=palm''dor level''dor 'state award'"`
}

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

    testCases := []Award{
        {"palm'dor"},    // Expected: Valid
        {"level'dor"},   // Expected: Valid
        {"state award"}, // Expected: Valid
        {"other"},       // Expected: Invalid
    }

    for _, testCase := range testCases {
        err := validate.Struct(testCase)
        if err != nil {
            fmt.Printf("Input: %q - Invalid (%v)\n", testCase.Title, err)
        } else {
            fmt.Printf("Input: %q - Valid\n", testCase.Title)
        }
    }
}

正确输出 #

Input: "palm'dor" - Valid
Input: "level'dor" - Valid
Input: "state award" - Valid
Input: "other" - Invalid (Key: 'Award.Title' Error:Field validation for 'Title' failed on the 'oneof' tag)

内容的提问来源于stack exchange，提问作者Aslam-Ep