mail/main.go
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package parsemail import ( "bytes" "io" "io/ioutil" "mime" "net/mail" "strings" ) // Parse an email message read from io.Reader into parsemail.Email struct func Parse(r io.Reader) (email Email, err error) { b, err := ioutil.ReadAll(r) if err != nil { return } reader := bytes.NewReader(b) msg, err := mail.ReadMessage(reader) if err != nil { return } email, err = createEmailFromHeader(msg.Header) if err != nil { return } email.Bytes = b return } func createEmailFromHeader(header mail.Header) (email Email, err error) { // todo: strip this down enormously, replace with anon funcs for email (mail.Subject, mail.To, etc) hp := headerParser{header: &header} email.Subject = decodeMimeSentence(header.Get("Subject")) email.From = hp.parseAddressList(header.Get("From")) email.Sender = hp.parseAddress(header.Get("Sender")) email.ReplyTo = hp.parseAddressList(header.Get("Reply-To")) email.To = hp.parseAddressList(header.Get("To")) email.Cc = hp.parseAddressList(header.Get("Cc")) email.Bcc = hp.parseAddressList(header.Get("Bcc")) if hp.err != nil { err = hp.err return } //decode whole header for easier access to extra fields //todo: should we decode? aren't only standard fields mime encoded? email.Header, err = decodeHeaderMime(header) if err != nil { return } return } func decodeMimeSentence(s string) string { result := []string{} ss := strings.Split(s, " ") for _, word := range ss { dec := new(mime.WordDecoder) w, err := dec.Decode(word) if err != nil { if len(result) == 0 { w = word } else { w = " " + word } } result = append(result, w) } return strings.Join(result, "") } func decodeHeaderMime(header mail.Header) (mail.Header, error) { parsedHeader := map[string][]string{} for headerName, headerData := range header { parsedHeaderData := []string{} for _, headerValue := range headerData { parsedHeaderData = append(parsedHeaderData, decodeMimeSentence(headerValue)) } parsedHeader[headerName] = parsedHeaderData } return mail.Header(parsedHeader), nil } type headerParser struct { header *mail.Header err error } func (hp headerParser) parseAddress(s string) (ma *mail.Address) { if hp.err != nil { return nil } if strings.Trim(s, " \n") != "" { ma, hp.err = mail.ParseAddress(s) return ma } return nil } func (hp headerParser) parseAddressList(s string) (ma []*mail.Address) { if hp.err != nil { return } if strings.Trim(s, " \n") != "" { ma, hp.err = mail.ParseAddressList(s) return } return } func (e *Email) ToBytes() []byte { var buf bytes.Buffer buf.Write(e.PrefixBytes) buf.Write(e.Bytes) return buf.Bytes() } // Email with fields for all the headers defined in RFC5322 with it's attachments and type Email struct { Header mail.Header // read-only Subject string Sender *mail.Address From []*mail.Address ReplyTo []*mail.Address To []*mail.Address Cc []*mail.Address Bcc []*mail.Address // read-write PrefixBytes []byte Bytes []byte // All bytes that can be replayed for a successful transmission }