accept.go RawHistoryFolder

1// SPDX-License-Identifier: MIT
2
3package registryproxy
4
5import (
6	"sort"
7	"strings"
8)
9
10var manifestTypes = []string{
11	"application/vnd.docker.distribution.manifest.v2+json",
12	"application/vnd.docker.distribution.manifest.list.v2+json",
13	"application/vnd.oci.image.manifest.v1+json",
14	"application/vnd.oci.image.index.v1+json",
15}
16
17// normalizeAccept bounds both negotiation and metadata cardinality to the
18// fifteen nonempty subsets of the supported manifest types.
19func normalizeAccept(raw string) string {
20	seen := map[string]bool{}
21	for _, part := range strings.Split(raw, ",") {
22		typ, _, _ := strings.Cut(part, ";")
23		typ = strings.ToLower(strings.TrimSpace(typ))
24		for _, known := range manifestTypes {
25			if typ == known {
26				seen[typ] = true
27			}
28		}
29	}
30	if len(seen) == 0 {
31		for _, typ := range manifestTypes {
32			seen[typ] = true
33		}
34	}
35	types := make([]string, 0, len(seen))
36	for typ := range seen {
37		types = append(types, typ)
38	}
39	sort.Strings(types)
40	return strings.Join(types, ",")
41}