1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
|
package token
import (
"fmt"
"strings"
"golang.org/x/net/idna"
"golang.org/x/text/unicode/norm"
)
// Normalizes a utf8 domain name.
func NormalizeDomainName(domain string) (string, error) {
n := norm.NFKC.String(domain) // Unicode normalization
l := strings.ToLower(n) // Unicode lowercase
a, err := idna.ToASCII(l) // A-label form (no-op for all-ascii labels)
if err != nil {
return "", fmt.Errorf("failed converting domain %q to a-label form: %v", l, err)
}
u, err := idna.ToUnicode(a)
if err != nil {
return "", fmt.Errorf("failed converting domain %q to u-label form: %v", a, err)
}
if !norm.NFKC.IsNormalString(u) {
return "", fmt.Errorf("a-label domain %q was decoded to un-normalized unicode %q",
a, u)
}
if strings.ToLower(u) != u {
return "", fmt.Errorf("a-label domain %q was decoded to not all-lowercase unicode %q",
a, u)
}
return u, nil
}
|
