| // Copyright 2012 The Go Authors. All rights reserved. |
| // Use of this source code is governed by a BSD-style |
| // license that can be found in the LICENSE file. |
| |
| // Package idna implements IDNA2008 (Internationalized Domain Names for |
| // Applications), defined in RFC 5890, RFC 5891, RFC 5892, RFC 5893 and |
| // RFC 5894. |
| package idna // import "golang.org/x/net/idna" |
| |
| import ( |
| "strings" |
| "unicode/utf8" |
| ) |
| |
| // TODO(nigeltao): specify when errors occur. For example, is ToASCII(".") or |
| // ToASCII("foo\x00") an error? See also http://www.unicode.org/faq/idn.html#11 |
| |
| // acePrefix is the ASCII Compatible Encoding prefix. |
| const acePrefix = "xn--" |
| |
| // ToASCII converts a domain or domain label to its ASCII form. For example, |
| // ToASCII("bücher.example.com") is "xn--bcher-kva.example.com", and |
| // ToASCII("golang") is "golang". |
| func ToASCII(s string) (string, error) { |
| if ascii(s) { |
| return s, nil |
| } |
| labels := strings.Split(s, ".") |
| for i, label := range labels { |
| if !ascii(label) { |
| a, err := encode(acePrefix, label) |
| if err != nil { |
| return "", err |
| } |
| labels[i] = a |
| } |
| } |
| return strings.Join(labels, "."), nil |
| } |
| |
| // ToUnicode converts a domain or domain label to its Unicode form. For example, |
| // ToUnicode("xn--bcher-kva.example.com") is "bücher.example.com", and |
| // ToUnicode("golang") is "golang". |
| func ToUnicode(s string) (string, error) { |
| if !strings.Contains(s, acePrefix) { |
| return s, nil |
| } |
| labels := strings.Split(s, ".") |
| for i, label := range labels { |
| if strings.HasPrefix(label, acePrefix) { |
| u, err := decode(label[len(acePrefix):]) |
| if err != nil { |
| return "", err |
| } |
| labels[i] = u |
| } |
| } |
| return strings.Join(labels, "."), nil |
| } |
| |
| func ascii(s string) bool { |
| for i := 0; i < len(s); i++ { |
| if s[i] >= utf8.RuneSelf { |
| return false |
| } |
| } |
| return true |
| } |