创建持续时间或将来日期的惯用方式

Question

What would be the idiomatic way of getting a duration between two dates or basically getting a future date based on the current. Right now I'm using the below code to achieve that.

yearSpan := time.Date(time.Now().Year()-1, time.Now().Month(), 
time.Now().Day(), time.Now().Hour(), time.Now().Minute(), time.Now().Second(), 
time.Now().Nanosecond(), time.UTC)

yearDuration := time.Now().Sub(yearSpan)

header.Add("Expires", time.Now().Add(futureDate).String())

I've pretty much looked everywhere in books and sites but I couldn't find any idiomatic way creating a duration. Any thoughts on how to refactor the above code in a better way?

Thanks

Answer 1

time.Duration is defined as type Duration int64, so basicly you just do basic math to get the duration you want.

For example (Play with it) :

package main

import (
    "fmt"
    "time"
)

const avgYear = time.Hour * 24 * 365

func main() {
    fmt.Println("Hello, playground")
    fmt.Println("Now", time.Now().String())
    fmt.Println("Last Year", time.Now().Add(-avgYear).String())
    fmt.Println("Next Year", time.Now().Add(avgYear).String())
}