go - 如何在 Go 中表示 RFC-3339 `-00:00` 偏移量？

Question

RFC-3339 第 4.3 节 ( https://www.rfc-editor.org/rfc/rfc3339#section-4.3 ) 定义 -00:00 偏移量如下，它不同于 Z 或 +00: 00。

4.3. Unknown Local Offset Convention

   If the time in UTC is known, but the offset to local time is unknown,
   this can be represented with an offset of "-00:00".  This differs
   semantically from an offset of "Z" or "+00:00", which imply that UTC
   is the preferred reference point for the specified time.  RFC2822
   [IMAIL-UPDATE] describes a similar convention for email.

但是，我不确定如何在 Go 中表示它。当我使用 -00:00 解析时间并对其进行格式化时，我得到了一个 Z 偏移量。例如:

• 输入:2018-01-01T00:00:00-00:00
• 输出:2018-01-01T00:00:00Z

这是一些示例代码 ( https://play.golang.org/p/CVmNnhaSiiT ):

package main

import (
    "fmt"
    "time"
)

func main() {
    t := "2018-01-01T00:00:00-00:00"
    fmt.Println("Input  " + t)
    p, err := time.Parse(time.RFC3339, t)
    if err != nil {
        fmt.Println(err)
    } else {
        t2 := p.Format(time.RFC3339)

        fmt.Println("Output " + t2)
    }
}

Answer 1

Package time

import "time"

RFC3339, RFC822, RFC822Z, RFC1123, and RFC1123Z are useful for formatting; when used with time.Parse they do not accept all the time formats permitted by the RFCs.

---

Go does not accept all the time formats permitted by the RFCs.

Go time.Time 类型使用整数，与 float 不同，整数没有正负零的概念。 -00:00和+00:00的偏移量解析结果是一样的。

例如，

package main

import (
    "fmt"
    "time"
)

func main() {
    var err error
    var minus, plus time.Time
    t := "2018-01-01T00:00:00-00:00"
    minus, err = time.Parse(time.RFC3339, t)
    if err != nil {
        fmt.Println(err)
    }
    t = "2018-01-01T00:00:00+00:00"
    plus, err = time.Parse(time.RFC3339, t)
    if err != nil {
        fmt.Println(err)
    }
    fmt.Println(minus, plus, minus.Equal(plus), minus == plus)
}

Playground :https://play.golang.org/p/Urf8VlKYoMH

输出:

2018-01-01 00:00:00 +0000 UTC 2018-01-01 00:00:00 +0000 UTC true true