mail/main.go
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
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
}