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Golang implementation for RFC 1342: Non-ASCII Mail Headers
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| package main | |
| import ( | |
| "encoding/base64" | |
| "fmt" | |
| "io" | |
| "io/ioutil" | |
| "mime/quotedprintable" | |
| "regexp" | |
| "strings" | |
| "golang.org/x/text/encoding" | |
| "golang.org/x/text/encoding/charmap" | |
| "golang.org/x/text/encoding/unicode" | |
| ) | |
| func decoder(encoding string) (*encoding.Decoder, error) { | |
| if strings.ToUpper(encoding) == "UTF-8" { | |
| return unicode.UTF8.NewDecoder(), nil | |
| } else if strings.ToUpper(encoding) == "ISO-8859-1" { | |
| return charmap.ISO8859_1.NewDecoder(), nil | |
| } else { | |
| return nil, fmt.Errorf("Unknown encoding") | |
| } | |
| } | |
| func decodeHeader(str string) (string, error) { | |
| re := regexp.MustCompile(`\=\?(?P<charset>.*?)\?(?P<encoding>.*)\?(?P<body>.*?)\?(.*?)\=`) | |
| matches := re.FindAllStringSubmatch(str, -1) | |
| if len(matches) == 0 { | |
| return str, nil | |
| } | |
| for _, match := range matches { | |
| var r io.Reader = strings.NewReader(match[3]) | |
| if match[2] == "Q" { | |
| r = quotedprintable.NewReader(r) | |
| } else if match[2] == "B" { | |
| r = base64.NewDecoder(base64.StdEncoding, r) | |
| } | |
| if d, err := decoder(match[1]); err == nil { | |
| r = d.Reader(r) | |
| } | |
| if val, err := ioutil.ReadAll(r); err == nil { | |
| str = strings.Replace(str, match[0], string(val), -1) | |
| } else if err != nil { | |
| fmt.Println(err.Error()) | |
| continue | |
| } | |
| } | |
| return str, nil | |
| } | |
| func main() { | |
| fmt.Println(decodeHeader("=?UTF-8?Q?=F3=BE=AC=8D_?= ... Laten we ontmoeten! Ik woon in de buurt ..")) | |
| fmt.Println(decodeHeader("=?ISO-8859-1?Q?Keld_J=F8rn_Simonsen?= <keld@dkuug.dk>")) | |
| } |
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