The current JSON serialization format is 2006-01-02 15:04:05.999999999. Is user-defined configuration allowed?

[shuqingzai]

参考：

• carbon/json.go

  Line 107 in 1e4801a

  func (t DateTime) MarshalJSON() ([]byte, error) {

• carbon/json.go

  Line 113 in 1e4801a

  func (t *DateTime) UnmarshalJSON(b []byte) error {

格式是使用固定的常量，用户没法修改，应该改为设置不同类型的全局变量，默认值就是目前的常量模板，让用户在程序启动时，可设置 JSON 序列化的模板

对于需要使用标准库的默认模板（带有时区 carbon.ISO8601Layout 或 carbon.RFC3339Layout )，目前无法实现，对于时区的掌控，我们需要交给前端部署的不同地区节点，自动转换，服务器统一使用 UTC

[gouguoyin]

At present, please expand the method yourself, such as:

type rfc3339 carbon.Carbon

func (t rfc3339) MarshalJSON() ([]byte, error) {
	return []byte(fmt.Sprintf(`"%s"`, t.ToRfc3339String())), nil
}

func (t *rfc3339) UnmarshalJSON(b []byte) error {
	c := carbon.ParseByLayout(string(bytes.Trim(b, `"`)), carbon.RFC3339Layout, t.Location())
	if c.Error == nil {
		*t = carbon.DateTime{Carbon: c}
	}
	return c.Error
}

[shuqingzai]

c := carbon.ParseByLayout(string(bytes.Trim(b, `"`)), carbon.RFC3339Layout, t.Location())
	if c.Error == nil {
		*t = carbon.DateTime{Carbon: c}
	}
	return c.Error

是的，我目前是这样的做，只是提个意见，用户可以自定义格式

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---

c := carbon.ParseByLayout(string(bytes.Trim(b, `"`)), carbon.RFC3339Layout, t.Location())
if c.Error == nil {
*t = carbon.DateTime{Carbon: c}
}
return c.Error

Yes, this is how I do it currently. I just want to give my opinion. Users can customize the format.

[gouguoyin]

The problem is

type Person struct {
    Birthday1 carbon.Carbon `json:"birthday1"`
    Birthday2 carbon.Carbon `json:"birthday2"`
}

I want birthday1 to display Y-m-d H:i:s format, birthday2 to display Y-m-d format.

How to distinguish different output formats of the same type? When should users be allowed to customize different formats?

[gouguoyin]

In v2.3.0, the tag mechanism is used for json user-defined encoding and decoding.

定义模型

type Person struct {
    Name string `json:"name"`
    Age int `json:"age"`
    Birthday carbon.Carbon `json:"birthday" carbon:"layout:2006-01-02"`
    GraduatedAt carbon.Carbon `json:"graduated_at" carbon:"layout:15:04:05"`
    CreatedAt carbon.Carbon `json:"created_at" carbon:"layout:2006-01-02 15:04:05"`
}

或

type Person struct {
    Name string `json:"name"`
    Age int `json:"age"`
    Birthday carbon.Carbon `json:"birthday" carbon:"format:Y-m-d"`
    GraduatedAt carbon.Carbon `json:"graduated_at" carbon:"format:H:i:s"`
    CreatedAt carbon.Carbon `json:"created_at" carbon:"format:Y-m-d H:i:s"`
}

实例化模型

now := Parse("2020-08-05 13:14:15", PRC)
person := Person {
    Name:        "gouguoyin",
    Age:         18,
    Birthday:    now,
    GraduatedAt: now,
    CreatedAt:   now,
}

JSON 编码

err1 := carbon.LoadTag(&person)
if err1 != nil {
    // 错误处理
    log.Fatal(err1)
}
data, err2 := json.Marshal(person)
if err2 != nil {
    // 错误处理
    log.Fatal(err2)
}
fmt.Printf("%s", data)
// 输出
{
    "name": "gouguoyin",
    "age": 18,
    "birthday": "2020-08-05",
    "graduated_at": "13:14:15",
    "created_at": "2020-08-05 13:14:15"
}

JSON 解码

str := `{
    "name": "gouguoyin",
    "age": 18,
    "birthday": "2020-08-05",
    "graduated_at": "13:14:15",
    "created_at": "2020-08-05 13:14:15"
}`
var person Person

err1 := carbon.LoadTag(&person)
if err1 != nil {
    // 错误处理
    log.Fatal(err1)
}

err2 := json.Unmarshal([]byte(str), &person)
if err2 != nil {
    // 错误处理
    log.Fatal(err2)
}

fmt.Sprintf("%s", person.Birthday) // 2002-08-05
fmt.Sprintf("%s", person.GraduatedAt) // 13:14:15
fmt.Sprintf("%s", person.CreatedAt) // 2002-08-05 13:14:15