GOPackageHeaderServer/web/utils/utils.go

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package utils
import (
"net/http"
"strconv"
"time"
)
func SetNeverCacheHeader(header http.Header) {
header.Set("Cache-Control", "max-age=0, no-cache, no-store, must-revalidate")
header.Set("Pragma", "no-cache")
}
func SetLastModifiedHeader(header http.Header, modTime time.Time) {
if !modTime.IsZero() {
header.Set("Last-Modified", modTime.UTC().Format(http.TimeFormat))
}
}
func SetCacheHeaderWithAge(header http.Header, maxAge uint, modifiedTime time.Time) {
header.Set("Cache-Control", "max-age="+strconv.Itoa(int(maxAge))+", must-revalidate")
if maxAge > 0 {
checkerSecondsBetween := int64(time.Now().UTC().Sub(modifiedTime.UTC()).Seconds())
if checkerSecondsBetween < 0 {
checkerSecondsBetween *= -1
}
header.Set("Age", strconv.FormatUint(uint64(checkerSecondsBetween)%uint64(maxAge), 10))
}
}
func SwitchToNonCachingHeaders(header http.Header) {
SetNeverCacheHeader(header)
if header.Get("Last-Modified") != "" {
header.Del("Last-Modified")
}
if header.Get("Age") != "" {
header.Del("Age")
}
if header.Get("Expires") != "" {
header.Del("Expires")
}
if header.Get("ETag") != "" {
header.Del("ETag")
}
}