parsemail.go - gomodules/forks/parsemail - Gitiles

 package parsemail

 import (
 	"net/mail"
 	"io"
 	"strings"
 	"mime/multipart"
 	"mime"
 	"fmt"
 	"errors"
 	"io/ioutil"
 	"time"
 	"encoding/base64"
 	"bytes"
 )

 const content_type_multipart_mixed = "multipart/mixed"
 const content_type_multipart_alternative = "multipart/alternative"
 const content_type_multipart_related = "multipart/related"
 const content_type_text_html = "text/html"
 const content_type_text_plain = "text/plain"

 func Parse(r io.Reader) (email Email, err error) {
 	msg, err := mail.ReadMessage(r);
 	if err != nil {
 		return
 	}

 	email, err = createEmailFromHeader(msg.Header)
 	if err != nil {
 		return
 	}

 	contentType, params, err := parseContentType(msg.Header.Get("Content-Type"))
 	if err != nil {
 		return
 	}

 	switch contentType {
 	case content_type_multipart_mixed:
 		email.TextBody, email.HTMLBody, email.Attachments, email.EmbeddedFiles, err = parseMultipartMixed(msg.Body, params["boundary"])
 	case content_type_multipart_alternative:
 		email.TextBody, email.HTMLBody, email.EmbeddedFiles, err = parseMultipartAlternative(msg.Body, params["boundary"])
 	case content_type_text_plain:
 		message, _ := ioutil.ReadAll(msg.Body)
 		email.TextBody = strings.TrimSuffix(string(message[:]), "\n")
 	case content_type_text_html:
 		message, _ := ioutil.ReadAll(msg.Body)
 		email.HTMLBody = strings.TrimSuffix(string(message[:]), "\n")
 	case "":
 		err = errors.New("No top level mime type specified")
 	default:
 		err = errors.New(fmt.Sprintf("Unknown top level mime type: %s", contentType))
 	}

 	return
 }

 func createEmailFromHeader(header mail.Header) (email Email, err error) {
 	email.Subject = header.Get("Subject")

 	email.From, err = parseAddressList(header.Get("From"))
 	if err != nil {
 		return
 	}

 	email.Sender, err = parseAddress(header.Get("Sender"))
 	if err != nil {
 		return
 	}

 	email.ReplyTo, err = parseAddressList(header.Get("Reply-To"))
 	if err != nil {
 		return
 	}

 	email.To, err = parseAddressList(header.Get("To"))
 	if err != nil {
 		return
 	}

 	email.Cc, err = parseAddressList(header.Get("Cc"))
 	if err != nil {
 		return
 	}

 	email.Bcc, err = parseAddressList(header.Get("Bcc"))
 	if err != nil {
 		return
 	}

 	email.Date, err = parseTime(header.Get("Date"))
 	if err != nil {
 		return
 	}

 	email.ResentFrom, err = parseAddressList(header.Get("Resent-From"))
 	if err != nil {
 		return
 	}

 	email.ResentSender, err = parseAddress(header.Get("Resent-Sender"))
 	if err != nil {
 		return
 	}

 	email.ResentTo, err = parseAddressList(header.Get("Resent-To"))
 	if err != nil {
 		return
 	}

 	email.ResentCc, err = parseAddressList(header.Get("Resent-Cc"))
 	if err != nil {
 		return
 	}

 	email.ResentBcc, err = parseAddressList(header.Get("Resent-Bcc"))
 	if err != nil {
 		return
 	}

 	if header.Get("Resent-Date") == "" {
 		email.ResentDate = time.Time{}
 	} else {
 		email.ResentDate, err = parseTime(header.Get("Resent-Date"))
 		if err != nil {
 			return
 		}
 	}

 	email.ResentMessageID = parseMessageId(header.Get("Resent-Message-ID"))
 	email.MessageID = parseMessageId(header.Get("Message-ID"))
 	email.InReplyTo = parseMessageIdList(header.Get("In-Reply-To"))
 	email.References = parseMessageIdList(header.Get("References"))

 	//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 parseContentType(contentTypeHeader string) (contentType string, params map[string]string, err error) {
 	if contentTypeHeader == "" {
 		contentType = content_type_text_plain
 		return
 	}

 	return mime.ParseMediaType(contentTypeHeader)
 }

 func parseAddress(s string) (*mail.Address, error) {
 	if strings.Trim(s, " \n") != "" {
 		return mail.ParseAddress(s)
 	}

 	return nil, nil
 }

 func parseAddressList(s string) ([]*mail.Address, error) {
 	if strings.Trim(s, " \n") != "" {
 		return mail.ParseAddressList(s)
 	}

 	return []*mail.Address{}, nil
 }

 func parseTime(s string) (time.Time, error) {
 	t, err := time.Parse(time.RFC1123Z, s)
 	if err == nil {
 		return t, err
 	}

 	return time.Parse("Mon, 2 Jan 2006 15:04:05 -0700", s)
 }

 func parseMessageId(s string) string {
 	return strings.Trim(s, "<> ")
 }

 func parseMessageIdList(s string) (result []string) {
 	for _, p := range(strings.Split(s, " ")) {
 		if strings.Trim(p, " \n") != "" {
 			result = append(result, parseMessageId(p))
 		}
 	}

 	return
 }

 func parseMultipartAlternative(msg io.Reader, boundary string) (textBody, htmlBody string, embeddedFiles []EmbeddedFile, err error) {
 	pmr := multipart.NewReader(msg, boundary)
 	for {
 		part, err := pmr.NextPart()

 		if err == io.EOF {
 			break
 		} else if err != nil {
 			return textBody, htmlBody, embeddedFiles, err
 		}

 		contentType, params, err := mime.ParseMediaType(part.Header.Get("Content-Type"))

 		switch contentType {
 		case content_type_text_plain:
 			ppContent, err := ioutil.ReadAll(part)
 			if err != nil {
 				return textBody, htmlBody, embeddedFiles, err
 			}

 			textBody += strings.TrimSuffix(string(ppContent[:]), "\n")
 		case content_type_text_html:
 			ppContent, err := ioutil.ReadAll(part)
 			if err != nil {
 				return textBody, htmlBody, embeddedFiles, err
 			}

 			htmlBody += strings.TrimSuffix(string(ppContent[:]), "\n")
 		case content_type_multipart_related:
 			var tb, hb string
 			var ef []EmbeddedFile
 			tb, hb, ef, err = parseMultipartAlternative(part, params["boundary"])
 			htmlBody += hb
 			textBody += tb
 			embeddedFiles = append(embeddedFiles, ef...)
 		default:
 			if isEmbeddedFile(part) {
 				ef, err := decodeEmbeddedFile(part)
 				if err != nil {
 					return textBody, htmlBody, embeddedFiles, err
 				}

 				embeddedFiles = append(embeddedFiles, ef)
 			} else {
 				return textBody, htmlBody, embeddedFiles, errors.New(fmt.Sprintf("Can't process multipart/alternative inner mime type: %s", contentType))
 			}
 		}
 	}

 	return textBody, htmlBody, embeddedFiles, err
 }

 func parseMultipartMixed(msg io.Reader, boundary string) (textBody, htmlBody string, attachments []Attachment, embeddedFiles []EmbeddedFile, err error) {
 	mr := multipart.NewReader(msg, boundary)
 	for {
 		part, err := mr.NextPart()
 		if err == io.EOF {
 			break
 		} else if err != nil {
 			return textBody, htmlBody, attachments, embeddedFiles, err
 		}

 		contentType, params, err := mime.ParseMediaType(part.Header.Get("Content-Type"))
 		if err != nil {
 			return textBody, htmlBody, attachments, embeddedFiles, err
 		}

 		if contentType == content_type_multipart_alternative {
 			textBody, htmlBody, embeddedFiles, err = parseMultipartAlternative(part, params["boundary"])
 			if err != nil {
 				return textBody, htmlBody, attachments, embeddedFiles, err
 			}
 		} else if isAttachment(part) {
 			at, err := decodeAttachment(part)
 			if err != nil {
 				return textBody, htmlBody, attachments, embeddedFiles, err
 			}

 			attachments = append(attachments, at)
 		} else {
 			return textBody, htmlBody, attachments, embeddedFiles, errors.New(fmt.Sprintf("Unknown multipart/mixed nested mime type: %s", contentType))
 		}
 	}

 	return textBody, htmlBody, attachments, embeddedFiles, err
 }

 func decodeMimeSentence(s string) (string, error) {
 	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, ""), nil
 }

 func decodeHeaderMime(header mail.Header) (mail.Header, error)  {
 	parsedHeader := map[string][]string{}

 	for headerName, headerData := range header {

 		parsedHeaderData := []string{}
 		for _, headerValue := range headerData {
 			decodedHeaderValue, err := decodeMimeSentence(headerValue)
 			if err != nil {
 				return mail.Header{}, err
 			}
 			parsedHeaderData = append(parsedHeaderData, decodedHeaderValue)
 		}

 		parsedHeader[headerName] = parsedHeaderData
 	}

 	return mail.Header(parsedHeader), nil
 }

 func decodePartData(part *multipart.Part) (io.Reader, error) {
 	encoding := part.Header.Get("Content-Transfer-Encoding")

 	if encoding == "base64" {
 		dr := base64.NewDecoder(base64.StdEncoding, part)
 		dd, err := ioutil.ReadAll(dr)
 		if err != nil {
 			return nil, err
 		}

 		return bytes.NewReader(dd), nil
 	} else {
 		return nil, errors.New(fmt.Sprintf("Unknown encoding: %s", encoding))
 	}
 }

 func isEmbeddedFile(part *multipart.Part) bool {
 	return part.Header.Get("Content-Transfer-Encoding") != ""
 }

 func decodeEmbeddedFile(part *multipart.Part) (ef EmbeddedFile, err error) {
 	cid, err := decodeMimeSentence(part.Header.Get("Content-Id"));
 	if err != nil {
 		return
 	}

 	decoded, err := decodePartData(part)
 	if err != nil {
 		return
 	}

 	ef.CID = strings.Trim(cid, "<>")
 	ef.Data = decoded
 	ef.ContentType = part.Header.Get("Content-Type")

 	return
 }

 func isAttachment(part *multipart.Part) bool {
 	return part.FileName() != ""
 }

 func decodeAttachment(part *multipart.Part) (at Attachment, err error) {
 	filename, err := decodeMimeSentence(part.FileName());
 	if err != nil {
 		return
 	}

 	decoded, err := decodePartData(part)
 	if err != nil {
 		return
 	}

 	at.Filename = filename
 	at.Data = decoded
 	at.ContentType = strings.Split(part.Header.Get("Content-Type"), ";")[0]

 	return
 }

 type Attachment struct {
 	Filename string
 	ContentType string
 	Data io.Reader
 }

 type EmbeddedFile struct {
 	CID string
 	ContentType string
 	Data io.Reader
 }

 type MessageID string

 type Email struct {
 	Header mail.Header

 	Subject string
 	Sender *mail.Address
 	From []*mail.Address
 	ReplyTo []*mail.Address
 	To []*mail.Address
 	Cc []*mail.Address
 	Bcc []*mail.Address
 	Date time.Time
 	MessageID string
 	InReplyTo []string
 	References []string

 	ResentFrom []*mail.Address
 	ResentSender *mail.Address
 	ResentTo []*mail.Address
 	ResentDate time.Time
 	ResentCc []*mail.Address
 	ResentBcc []*mail.Address
 	ResentMessageID string

 	Received string

 	HTMLBody string
 	TextBody string

 	Attachments []Attachment
 	EmbeddedFiles []EmbeddedFile
 }
	package parsemail

	import (
	"net/mail"
	"io"
	"strings"
	"mime/multipart"
	"mime"
	"fmt"
	"errors"
	"io/ioutil"
	"time"
	"encoding/base64"
	"bytes"
	)

	const content_type_multipart_mixed = "multipart/mixed"
	const content_type_multipart_alternative = "multipart/alternative"
	const content_type_multipart_related = "multipart/related"
	const content_type_text_html = "text/html"
	const content_type_text_plain = "text/plain"

	func Parse(r io.Reader) (email Email, err error) {
	msg, err := mail.ReadMessage(r);
	if err != nil {
	return
	}

	email, err = createEmailFromHeader(msg.Header)
	if err != nil {
	return
	}

	contentType, params, err := parseContentType(msg.Header.Get("Content-Type"))
	if err != nil {
	return
	}

	switch contentType {
	case content_type_multipart_mixed:
	email.TextBody, email.HTMLBody, email.Attachments, email.EmbeddedFiles, err = parseMultipartMixed(msg.Body, params["boundary"])
	case content_type_multipart_alternative:
	email.TextBody, email.HTMLBody, email.EmbeddedFiles, err = parseMultipartAlternative(msg.Body, params["boundary"])
	case content_type_text_plain:
	message, _ := ioutil.ReadAll(msg.Body)
	email.TextBody = strings.TrimSuffix(string(message[:]), "\n")
	case content_type_text_html:
	message, _ := ioutil.ReadAll(msg.Body)
	email.HTMLBody = strings.TrimSuffix(string(message[:]), "\n")
	case "":
	err = errors.New("No top level mime type specified")
	default:
	err = errors.New(fmt.Sprintf("Unknown top level mime type: %s", contentType))
	}

	return
	}

	func createEmailFromHeader(header mail.Header) (email Email, err error) {
	email.Subject = header.Get("Subject")

	email.From, err = parseAddressList(header.Get("From"))
	if err != nil {
	return
	}

	email.Sender, err = parseAddress(header.Get("Sender"))
	if err != nil {
	return
	}

	email.ReplyTo, err = parseAddressList(header.Get("Reply-To"))
	if err != nil {
	return
	}

	email.To, err = parseAddressList(header.Get("To"))
	if err != nil {
	return
	}

	email.Cc, err = parseAddressList(header.Get("Cc"))
	if err != nil {
	return
	}

	email.Bcc, err = parseAddressList(header.Get("Bcc"))
	if err != nil {
	return
	}

	email.Date, err = parseTime(header.Get("Date"))
	if err != nil {
	return
	}

	email.ResentFrom, err = parseAddressList(header.Get("Resent-From"))
	if err != nil {
	return
	}

	email.ResentSender, err = parseAddress(header.Get("Resent-Sender"))
	if err != nil {
	return
	}

	email.ResentTo, err = parseAddressList(header.Get("Resent-To"))
	if err != nil {
	return
	}

	email.ResentCc, err = parseAddressList(header.Get("Resent-Cc"))
	if err != nil {
	return
	}

	email.ResentBcc, err = parseAddressList(header.Get("Resent-Bcc"))
	if err != nil {
	return
	}

	if header.Get("Resent-Date") == "" {
	email.ResentDate = time.Time{}
	} else {
	email.ResentDate, err = parseTime(header.Get("Resent-Date"))
	if err != nil {
	return
	}
	}

	email.ResentMessageID = parseMessageId(header.Get("Resent-Message-ID"))
	email.MessageID = parseMessageId(header.Get("Message-ID"))
	email.InReplyTo = parseMessageIdList(header.Get("In-Reply-To"))
	email.References = parseMessageIdList(header.Get("References"))

	//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 parseContentType(contentTypeHeader string) (contentType string, params map[string]string, err error) {
	if contentTypeHeader == "" {
	contentType = content_type_text_plain
	return
	}

	return mime.ParseMediaType(contentTypeHeader)
	}

	func parseAddress(s string) (*mail.Address, error) {
	if strings.Trim(s, " \n") != "" {
	return mail.ParseAddress(s)
	}

	return nil, nil
	}

	func parseAddressList(s string) ([]*mail.Address, error) {
	if strings.Trim(s, " \n") != "" {
	return mail.ParseAddressList(s)
	}

	return []*mail.Address{}, nil
	}

	func parseTime(s string) (time.Time, error) {
	t, err := time.Parse(time.RFC1123Z, s)
	if err == nil {
	return t, err
	}

	return time.Parse("Mon, 2 Jan 2006 15:04:05 -0700", s)
	}

	func parseMessageId(s string) string {
	return strings.Trim(s, "<> ")
	}

	func parseMessageIdList(s string) (result []string) {
	for _, p := range(strings.Split(s, " ")) {
	if strings.Trim(p, " \n") != "" {
	result = append(result, parseMessageId(p))
	}
	}

	return
	}

	func parseMultipartAlternative(msg io.Reader, boundary string) (textBody, htmlBody string, embeddedFiles []EmbeddedFile, err error) {
	pmr := multipart.NewReader(msg, boundary)
	for {
	part, err := pmr.NextPart()

	if err == io.EOF {
	break
	} else if err != nil {
	return textBody, htmlBody, embeddedFiles, err
	}

	contentType, params, err := mime.ParseMediaType(part.Header.Get("Content-Type"))

	switch contentType {
	case content_type_text_plain:
	ppContent, err := ioutil.ReadAll(part)
	if err != nil {
	return textBody, htmlBody, embeddedFiles, err
	}

	textBody += strings.TrimSuffix(string(ppContent[:]), "\n")
	case content_type_text_html:
	ppContent, err := ioutil.ReadAll(part)
	if err != nil {
	return textBody, htmlBody, embeddedFiles, err
	}

	htmlBody += strings.TrimSuffix(string(ppContent[:]), "\n")
	case content_type_multipart_related:
	var tb, hb string
	var ef []EmbeddedFile
	tb, hb, ef, err = parseMultipartAlternative(part, params["boundary"])
	htmlBody += hb
	textBody += tb
	embeddedFiles = append(embeddedFiles, ef...)
	default:
	if isEmbeddedFile(part) {
	ef, err := decodeEmbeddedFile(part)
	if err != nil {
	return textBody, htmlBody, embeddedFiles, err
	}

	embeddedFiles = append(embeddedFiles, ef)
	} else {
	return textBody, htmlBody, embeddedFiles, errors.New(fmt.Sprintf("Can't process multipart/alternative inner mime type: %s", contentType))
	}
	}
	}

	return textBody, htmlBody, embeddedFiles, err
	}

	func parseMultipartMixed(msg io.Reader, boundary string) (textBody, htmlBody string, attachments []Attachment, embeddedFiles []EmbeddedFile, err error) {
	mr := multipart.NewReader(msg, boundary)
	for {
	part, err := mr.NextPart()
	if err == io.EOF {
	break
	} else if err != nil {
	return textBody, htmlBody, attachments, embeddedFiles, err
	}

	contentType, params, err := mime.ParseMediaType(part.Header.Get("Content-Type"))
	if err != nil {
	return textBody, htmlBody, attachments, embeddedFiles, err
	}

	if contentType == content_type_multipart_alternative {
	textBody, htmlBody, embeddedFiles, err = parseMultipartAlternative(part, params["boundary"])
	if err != nil {
	return textBody, htmlBody, attachments, embeddedFiles, err
	}
	} else if isAttachment(part) {
	at, err := decodeAttachment(part)
	if err != nil {
	return textBody, htmlBody, attachments, embeddedFiles, err
	}

	attachments = append(attachments, at)
	} else {
	return textBody, htmlBody, attachments, embeddedFiles, errors.New(fmt.Sprintf("Unknown multipart/mixed nested mime type: %s", contentType))
	}
	}

	return textBody, htmlBody, attachments, embeddedFiles, err
	}

	func decodeMimeSentence(s string) (string, error) {
	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, ""), nil
	}

	func decodeHeaderMime(header mail.Header) (mail.Header, error) {
	parsedHeader := map[string][]string{}

	for headerName, headerData := range header {

	parsedHeaderData := []string{}
	for _, headerValue := range headerData {
	decodedHeaderValue, err := decodeMimeSentence(headerValue)
	if err != nil {
	return mail.Header{}, err
	}
	parsedHeaderData = append(parsedHeaderData, decodedHeaderValue)
	}

	parsedHeader[headerName] = parsedHeaderData
	}

	return mail.Header(parsedHeader), nil
	}

	func decodePartData(part *multipart.Part) (io.Reader, error) {
	encoding := part.Header.Get("Content-Transfer-Encoding")

	if encoding == "base64" {
	dr := base64.NewDecoder(base64.StdEncoding, part)
	dd, err := ioutil.ReadAll(dr)
	if err != nil {
	return nil, err
	}

	return bytes.NewReader(dd), nil
	} else {
	return nil, errors.New(fmt.Sprintf("Unknown encoding: %s", encoding))
	}
	}

	func isEmbeddedFile(part *multipart.Part) bool {
	return part.Header.Get("Content-Transfer-Encoding") != ""
	}

	func decodeEmbeddedFile(part *multipart.Part) (ef EmbeddedFile, err error) {
	cid, err := decodeMimeSentence(part.Header.Get("Content-Id"));
	if err != nil {
	return
	}

	decoded, err := decodePartData(part)
	if err != nil {
	return
	}

	ef.CID = strings.Trim(cid, "<>")
	ef.Data = decoded
	ef.ContentType = part.Header.Get("Content-Type")

	return
	}

	func isAttachment(part *multipart.Part) bool {
	return part.FileName() != ""
	}

	func decodeAttachment(part *multipart.Part) (at Attachment, err error) {
	filename, err := decodeMimeSentence(part.FileName());
	if err != nil {
	return
	}

	decoded, err := decodePartData(part)
	if err != nil {
	return
	}

	at.Filename = filename
	at.Data = decoded
	at.ContentType = strings.Split(part.Header.Get("Content-Type"), ";")[0]

	return
	}

	type Attachment struct {
	Filename string
	ContentType string
	Data io.Reader
	}

	type EmbeddedFile struct {
	CID string
	ContentType string
	Data io.Reader
	}

	type MessageID string

	type Email struct {
	Header mail.Header

	Subject string
	Sender *mail.Address
	From []*mail.Address
	ReplyTo []*mail.Address
	To []*mail.Address
	Cc []*mail.Address
	Bcc []*mail.Address
	Date time.Time
	MessageID string
	InReplyTo []string
	References []string

	ResentFrom []*mail.Address
	ResentSender *mail.Address
	ResentTo []*mail.Address
	ResentDate time.Time
	ResentCc []*mail.Address
	ResentBcc []*mail.Address
	ResentMessageID string

	Received string

	HTMLBody string
	TextBody string

	Attachments []Attachment
	EmbeddedFiles []EmbeddedFile
	}