gitea/vendor/gopkg.in/gomail.v2/writeto.go
2016-11-04 08:43:11 +01:00

307 lines
6.6 KiB
Go
Vendored

package gomail
import (
"encoding/base64"
"errors"
"io"
"mime"
"mime/multipart"
"path/filepath"
"strings"
"time"
)
// WriteTo implements io.WriterTo. It dumps the whole message into w.
func (m *Message) WriteTo(w io.Writer) (int64, error) {
mw := &messageWriter{w: w}
mw.writeMessage(m)
return mw.n, mw.err
}
func (w *messageWriter) writeMessage(m *Message) {
if _, ok := m.header["Mime-Version"]; !ok {
w.writeString("Mime-Version: 1.0\r\n")
}
if _, ok := m.header["Date"]; !ok {
w.writeHeader("Date", m.FormatDate(now()))
}
w.writeHeaders(m.header)
if m.hasMixedPart() {
w.openMultipart("mixed")
}
if m.hasRelatedPart() {
w.openMultipart("related")
}
if m.hasAlternativePart() {
w.openMultipart("alternative")
}
for _, part := range m.parts {
w.writePart(part, m.charset)
}
if m.hasAlternativePart() {
w.closeMultipart()
}
w.addFiles(m.embedded, false)
if m.hasRelatedPart() {
w.closeMultipart()
}
w.addFiles(m.attachments, true)
if m.hasMixedPart() {
w.closeMultipart()
}
}
func (m *Message) hasMixedPart() bool {
return (len(m.parts) > 0 && len(m.attachments) > 0) || len(m.attachments) > 1
}
func (m *Message) hasRelatedPart() bool {
return (len(m.parts) > 0 && len(m.embedded) > 0) || len(m.embedded) > 1
}
func (m *Message) hasAlternativePart() bool {
return len(m.parts) > 1
}
type messageWriter struct {
w io.Writer
n int64
writers [3]*multipart.Writer
partWriter io.Writer
depth uint8
err error
}
func (w *messageWriter) openMultipart(mimeType string) {
mw := multipart.NewWriter(w)
contentType := "multipart/" + mimeType + ";\r\n boundary=" + mw.Boundary()
w.writers[w.depth] = mw
if w.depth == 0 {
w.writeHeader("Content-Type", contentType)
w.writeString("\r\n")
} else {
w.createPart(map[string][]string{
"Content-Type": {contentType},
})
}
w.depth++
}
func (w *messageWriter) createPart(h map[string][]string) {
w.partWriter, w.err = w.writers[w.depth-1].CreatePart(h)
}
func (w *messageWriter) closeMultipart() {
if w.depth > 0 {
w.writers[w.depth-1].Close()
w.depth--
}
}
func (w *messageWriter) writePart(p *part, charset string) {
w.writeHeaders(map[string][]string{
"Content-Type": {p.contentType + "; charset=" + charset},
"Content-Transfer-Encoding": {string(p.encoding)},
})
w.writeBody(p.copier, p.encoding)
}
func (w *messageWriter) addFiles(files []*file, isAttachment bool) {
for _, f := range files {
if _, ok := f.Header["Content-Type"]; !ok {
mediaType := mime.TypeByExtension(filepath.Ext(f.Name))
if mediaType == "" {
mediaType = "application/octet-stream"
}
f.setHeader("Content-Type", mediaType+`; name="`+f.Name+`"`)
}
if _, ok := f.Header["Content-Transfer-Encoding"]; !ok {
f.setHeader("Content-Transfer-Encoding", string(Base64))
}
if _, ok := f.Header["Content-Disposition"]; !ok {
var disp string
if isAttachment {
disp = "attachment"
} else {
disp = "inline"
}
f.setHeader("Content-Disposition", disp+`; filename="`+f.Name+`"`)
}
if !isAttachment {
if _, ok := f.Header["Content-ID"]; !ok {
f.setHeader("Content-ID", "<"+f.Name+">")
}
}
w.writeHeaders(f.Header)
w.writeBody(f.CopyFunc, Base64)
}
}
func (w *messageWriter) Write(p []byte) (int, error) {
if w.err != nil {
return 0, errors.New("gomail: cannot write as writer is in error")
}
var n int
n, w.err = w.w.Write(p)
w.n += int64(n)
return n, w.err
}
func (w *messageWriter) writeString(s string) {
n, _ := io.WriteString(w.w, s)
w.n += int64(n)
}
func (w *messageWriter) writeHeader(k string, v ...string) {
w.writeString(k)
if len(v) == 0 {
w.writeString(":\r\n")
return
}
w.writeString(": ")
// Max header line length is 78 characters in RFC 5322 and 76 characters
// in RFC 2047. So for the sake of simplicity we use the 76 characters
// limit.
charsLeft := 76 - len(k) - len(": ")
for i, s := range v {
// If the line is already too long, insert a newline right away.
if charsLeft < 1 {
if i == 0 {
w.writeString("\r\n ")
} else {
w.writeString(",\r\n ")
}
charsLeft = 75
} else if i != 0 {
w.writeString(", ")
charsLeft -= 2
}
// While the header content is too long, fold it by inserting a newline.
for len(s) > charsLeft {
s = w.writeLine(s, charsLeft)
charsLeft = 75
}
w.writeString(s)
if i := lastIndexByte(s, '\n'); i != -1 {
charsLeft = 75 - (len(s) - i - 1)
} else {
charsLeft -= len(s)
}
}
w.writeString("\r\n")
}
func (w *messageWriter) writeLine(s string, charsLeft int) string {
// If there is already a newline before the limit. Write the line.
if i := strings.IndexByte(s, '\n'); i != -1 && i < charsLeft {
w.writeString(s[:i+1])
return s[i+1:]
}
for i := charsLeft - 1; i >= 0; i-- {
if s[i] == ' ' {
w.writeString(s[:i])
w.writeString("\r\n ")
return s[i+1:]
}
}
// We could not insert a newline cleanly so look for a space or a newline
// even if it is after the limit.
for i := 75; i < len(s); i++ {
if s[i] == ' ' {
w.writeString(s[:i])
w.writeString("\r\n ")
return s[i+1:]
}
if s[i] == '\n' {
w.writeString(s[:i+1])
return s[i+1:]
}
}
// Too bad, no space or newline in the whole string. Just write everything.
w.writeString(s)
return ""
}
func (w *messageWriter) writeHeaders(h map[string][]string) {
if w.depth == 0 {
for k, v := range h {
if k != "Bcc" {
w.writeHeader(k, v...)
}
}
} else {
w.createPart(h)
}
}
func (w *messageWriter) writeBody(f func(io.Writer) error, enc Encoding) {
var subWriter io.Writer
if w.depth == 0 {
w.writeString("\r\n")
subWriter = w.w
} else {
subWriter = w.partWriter
}
if enc == Base64 {
wc := base64.NewEncoder(base64.StdEncoding, newBase64LineWriter(subWriter))
w.err = f(wc)
wc.Close()
} else if enc == Unencoded {
w.err = f(subWriter)
} else {
wc := newQPWriter(subWriter)
w.err = f(wc)
wc.Close()
}
}
// As required by RFC 2045, 6.7. (page 21) for quoted-printable, and
// RFC 2045, 6.8. (page 25) for base64.
const maxLineLen = 76
// base64LineWriter limits text encoded in base64 to 76 characters per line
type base64LineWriter struct {
w io.Writer
lineLen int
}
func newBase64LineWriter(w io.Writer) *base64LineWriter {
return &base64LineWriter{w: w}
}
func (w *base64LineWriter) Write(p []byte) (int, error) {
n := 0
for len(p)+w.lineLen > maxLineLen {
w.w.Write(p[:maxLineLen-w.lineLen])
w.w.Write([]byte("\r\n"))
p = p[maxLineLen-w.lineLen:]
n += maxLineLen - w.lineLen
w.lineLen = 0
}
w.w.Write(p)
w.lineLen += len(p)
return n + len(p), nil
}
// Stubbed out for testing.
var now = time.Now