Function parseCacheControl

filters/cache/cache_control.go:70–105

parseCacheControl parses Cache-Control response directives from h. Uses Header.Values to handle multiple header lines; matches names case-insensitively per RFC 9111 §5.2.

(h http.Header)

// Uses Header.Values to handle multiple header lines; matches names
// case-insensitively per RFC 9111 §5.2.
func parseCacheControl(h http.Header) cacheDirectives {
	d := cacheDirectives{maxAge: -1, sMaxAge: -1}
	for _, line := range h.Values("Cache-Control") {
		for token := range strings.SplitSeq(line, ",") {
			parts := strings.SplitN(strings.TrimSpace(token), "=", 2)
			directive := strings.ToLower(strings.TrimSpace(parts[0]))
			switch directive {
			case "no-store":
				d.noStore = true
			case "no-cache":
				d.noCache = true
			case "private":
				d.private = true
			case "must-revalidate":
				d.mustRevalidate = true
			case "proxy-revalidate":
				d.proxyRevalidate = true
			case "public":
				d.public = true
			case "max-age":
				if len(parts) == 2 {
					if v, err := strconv.ParseInt(strings.TrimSpace(parts[1]), 10, 64); err == nil {
						d.maxAge = v
					}
				}
			case "s-maxage":
				if len(parts) == 2 {
					if v, err := strconv.ParseInt(strings.TrimSpace(parts[1]), 10, 64); err == nil {
						d.sMaxAge = v
					}
				}
			}
		}
	}
	return d
}