如何在Golang中使用dyanmic键解析yaml

我试图用go来解析一个yaml文件.问题是yaml文件中的键可能并不总是相同.这是为了进行API版本控制,因此用户可以定义它们支持的版本.例如V1,V2,V3等.它们不需要按顺序排列,可以省略不支持IE V0,V5等的版本.

package main

import (
  "fmt"
  "gopkg.in/yaml.v2"
)

var data = `
---
development:
  skip-header-validation: true
  V1:
    current: "1.0.0"
    mime_types:
      - application/vnd.company.jk.identity+json;
      - application/vnd.company.jk.user+json;
      - application/vnd.company.jk.role+json;
      - application/vnd.company.jk.scope+json;
      - application/vnd.company.jk.test+json;
    skip-mime-type-validation: true
    skip-version-validation: true
  V2:
    current: "2.0.0"
    mime_types:
      - application/vnd.company.jk.identity+json;
      - application/vnd.company.jk.user+json;
      - application/vnd.company.jk.role+json;
      - application/vnd.company.jk.scope+json;
      - application/vnd.company.jk.test+json;

`

type MajorVersion struct {
  Current                 string    `yaml:"current"`
  MimeTypes               []string  `yaml:"mime_types"`
  SkipVersionValidation   bool      `yaml:"skip-version-validation"`
  SkipMimeTypeValidation  bool      `yaml:"skip-mime-type-validation"`
}

type Environment struct {
  SkipHeaderValidation  bool        `yaml:"skip-header-validation"`
  Version               map[string]MajorVersion
}

func main() {
  e := Environment{}

  yaml.Unmarshal([]byte(data),&e)
  fmt.Println(e)
}

我在这里看到了一个类似的问题Golang parse a json with DYNAMIC key
这是在顶层,并没有完全弄清楚如何从结构内部做到这一点.

首先,您尝试将根解析为环境,但其实际类型是map [string] Environment.其次,如果要保留该类型结构,则需要自定义 Unmarshaler.像这样的东西：

package main

import (
    "fmt"

    "gopkg.in/yaml.v2"
)

var data = `
---
development:
  skip-header-validation: true
  V1:
    current: "1.0.0"
    mime_types:
      - application/vnd.company.jk.identity+json;
      - application/vnd.company.jk.user+json;
      - application/vnd.company.jk.role+json;
      - application/vnd.company.jk.scope+json;
      - application/vnd.company.jk.test+json;
    skip-mime-type-validation: true
    skip-version-validation: true
  V2:
    current: "2.0.0"
    mime_types:
      - application/vnd.company.jk.identity+json;
      - application/vnd.company.jk.user+json;
      - application/vnd.company.jk.role+json;
      - application/vnd.company.jk.scope+json;
      - application/vnd.company.jk.test+json;

`

type MajorVersion struct {
    Current                string   `yaml:"current"`
    MimeTypes              []string `yaml:"mime_types"`
    SkipVersionValidation  bool     `yaml:"skip-version-validation"`
    SkipMimeTypeValidation bool     `yaml:"skip-mime-type-validation"`
}

type Environment struct {
    SkipHeaderValidation bool
    Versions             map[string]MajorVersion
}

func (e *Environment) UnmarshalYAML(unmarshal func(interface{}) error) error {
    var params struct {
        SkipHeaderValidation bool `yaml:"skip-header-validation"`
    }
    if err := unmarshal(&params); err != nil {
        return err
    }
    var versions map[string]MajorVersion
    if err := unmarshal(&versions); err != nil {
        // Here we expect an error because a boolean cannot be converted to a
        // a MajorVersion
        if _,ok := err.(*yaml.TypeError); !ok {
            return err
        }
    }
    e.SkipHeaderValidation = params.SkipHeaderValidation
    e.Versions = versions
    return nil
}

func main() {
    var e map[string]Environment
    if err := yaml.Unmarshal([]byte(data),&e); err != nil {
        fmt.Println(err.Error())
    }
    fmt.Printf("%#v\n",e)
}

输出(使用makeup后)：

map[string]main.Environment{
    "development": {
        SkipHeaderValidation: true,Versions:             {
            "V2": {
                Current:                "2.0.0",MimeTypes:              {"application/vnd.company.jk.identity+json;","application/vnd.company.jk.user+json;","application/vnd.company.jk.role+json;","application/vnd.company.jk.scope+json;","application/vnd.company.jk.test+json;"},SkipVersionValidation:  false,SkipMimeTypeValidation: false,},"V1": {
                Current:                "1.0.0",SkipVersionValidation:  true,SkipMimeTypeValidation: true,}