39 lines
1.1 KiB
Go
39 lines
1.1 KiB
Go
|
// Copyright 2018 Frédéric Guillot. All rights reserved.
|
||
|
|
// Use of this source code is governed by the Apache 2.0
|
||
|
|
// license that can be found in the LICENSE file.
|
||
|
|
|
||
|
|
package encoding
|
||
|
|
|
||
|
|
import (
|
||
|
|
"bytes"
|
||
|
|
"io"
|
||
|
|
"unicode/utf8"
|
||
|
|
|
||
|
|
"golang.org/x/net/html/charset"
|
||
|
|
)
|
||
|
|
|
||
|
|
// CharsetReader is used when the XML encoding is specified for the input document.
|
||
|
|
//
|
||
|
|
// The document is converted in UTF-8 only if a different encoding is specified
|
||
|
|
// and the document is not already UTF-8.
|
||
|
|
//
|
||
|
|
// Several edge cases could exists:
|
||
|
|
//
|
||
|
|
// - Feeds with charset specified only in Content-Type header and not in XML document
|
||
|
|
// - Feeds with charset specified in both places
|
||
|
|
// - Feeds with charset specified only in XML document and not in HTTP header
|
||
|
|
func CharsetReader(label string, input io.Reader) (io.Reader, error) {
|
||
|
|
var buf1, buf2 bytes.Buffer
|
||
|
|
w := io.MultiWriter(&buf1, &buf2)
|
||
|
|
io.Copy(w, input)
|
||
|
|
r := bytes.NewReader(buf2.Bytes())
|
||
|
|
|
||
|
|
if !utf8.Valid(buf1.Bytes()) {
|
||
|
|
// Transform document to UTF-8 from the specified XML encoding.
|
||
|
|
return charset.NewReaderLabel(label, r)
|
||
|
|
}
|
||
|
|
|
||
|
|
// The document is already UTF-8, do not do anything (avoid double-encoding)
|
||
|
|
return r, nil
|
||
|
|
}
|