Support cjk encoding

Author: gonejack

email.go

@@ -24,6 +24,9 @@ import (
 	"strings"
 	"time"
 	"unicode"
+
+	"golang.org/x/text/encoding/htmlindex"
+	"golang.org/x/text/transform"
 )
 
 const (
@@ -90,7 +93,7 @@ func handleAddressList(v []string) []string {
 	for _, a := range v {
 		w := strings.Split(a, ",")
 		for _, addr := range w {
-			decodedAddr, err := (&mime.WordDecoder{}).DecodeHeader(strings.TrimSpace(addr))
+			decodedAddr, err := wordDecoder.DecodeHeader(strings.TrimSpace(addr))
 			if err == nil {
 				res = append(res, decodedAddr)
 			} else {
@@ -118,7 +121,7 @@ func NewEmailFromReader(r io.Reader) (*Email, error) {
 		switch h {
 		case "Subject":
 			e.Subject = v[0]
-			subj, err := (&mime.WordDecoder{}).DecodeHeader(e.Subject)
+			subj, err := wordDecoder.DecodeHeader(e.Subject)
 			if err == nil && len(subj) > 0 {
 				e.Subject = subj
 			}
@@ -137,7 +140,7 @@ func NewEmailFromReader(r io.Reader) (*Email, error) {
 			delete(hdrs, h)
 		case "From":
 			e.From = v[0]
-			fr, err := (&mime.WordDecoder{}).DecodeHeader(e.From)
+			fr, err := wordDecoder.DecodeHeader(e.From)
 			if err == nil && len(fr) > 0 {
 				e.From = fr
 			}
@@ -216,7 +219,7 @@ func parseMIMEParts(hs textproto.MIMEHeader, b io.Reader) ([]*part, error) {
 			if _, ok := p.Header["Content-Type"]; !ok {
 				p.Header.Set("Content-Type", defaultContentType)
 			}
-			subct, _, err := mime.ParseMediaType(p.Header.Get("Content-Type"))
+			subct, subps, err := mime.ParseMediaType(p.Header.Get("Content-Type"))
 			if err != nil {
 				return ps, err
 			}
@@ -232,6 +235,15 @@ func parseMIMEParts(hs textproto.MIMEHeader, b io.Reader) ([]*part, error) {
 				const cte = "Content-Transfer-Encoding"
 				if p.Header.Get(cte) == "base64" {
 					reader = base64.NewDecoder(base64.StdEncoding, reader)
+
+					reader = base64.NewDecoder(base64.StdEncoding, reader)
+
+					if strings.HasPrefix(subct, "text") && subps["charset"] != "" {
+						transReader, err := wordDecoder.CharsetReader(subps["charset"], reader)
+						if err == nil {
+							reader = transReader
+						}
+					}
 				}
 				// Otherwise, just append the part to the list
 				// Copy the part data into the buffer
@@ -807,3 +819,13 @@ func generateMessageID() (string, error) {
 	msgid := fmt.Sprintf("<%d.%d.%d@%s>", t, pid, rint, h)
 	return msgid, nil
 }
+
+var wordDecoder = &mime.WordDecoder{
+	CharsetReader: func(charset string, input io.Reader) (io.Reader, error) {
+		encoding, err := htmlindex.Get(charset)
+		if err != nil {
+			return nil, err
+		}
+		return transform.NewReader(input, encoding.NewDecoder()), nil
+	},
+}