aboutsummaryrefslogtreecommitdiffstats
path: root/worker/lib/parse.go
blob: a14a6d33f938676902682fe77e3829b8890d3144 (plain) (blame)
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
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
package lib

import (
	"bytes"
	"errors"
	"fmt"
	"io"
	"regexp"
	"strings"
	"time"

	"git.sr.ht/~sircmpwn/aerc/models"
	"github.com/emersion/go-message"
	_ "github.com/emersion/go-message/charset"
	"github.com/emersion/go-message/mail"
)

// RFC 1123Z regexp
var dateRe = regexp.MustCompile(`(((Mon|Tue|Wed|Thu|Fri|Sat|Sun))[,]?\s[0-9]{1,2})\s` +
	`(Jan|Feb|Mar|Apr|May|Jun|Jul|Aug|Sep|Oct|Nov|Dec)\s` +
	`([0-9]{4})\s([0-9]{2}):([0-9]{2})(:([0-9]{2}))?\s([\+|\-][0-9]{4})\s?`)

func FetchEntityPartReader(e *message.Entity, index []int) (io.Reader, error) {
	if len(index) == 0 {
		// non multipart, simply return everything
		return bufReader(e)
	}
	if mpr := e.MultipartReader(); mpr != nil {
		idx := 0
		for {
			idx++
			part, err := mpr.NextPart()
			if err != nil {
				return nil, err
			}
			if idx == index[0] {
				rest := index[1:]
				if len(rest) < 1 {
					return bufReader(part)
				}
				return FetchEntityPartReader(part, index[1:])
			}
		}
	}
	return nil, fmt.Errorf("FetchEntityPartReader: unexpected code reached")
}

//TODO: the UI doesn't seem to like readers which aren't buffers
func bufReader(e *message.Entity) (io.Reader, error) {
	var buf bytes.Buffer
	if _, err := io.Copy(&buf, e.Body); err != nil {
		return nil, err
	}
	return &buf, nil
}

// split a MIME type into its major and minor parts
func splitMIME(m string) (string, string) {
	parts := strings.Split(m, "/")
	if len(parts) != 2 {
		return parts[0], ""
	}
	return parts[0], parts[1]
}

func ParseEntityStructure(e *message.Entity) (*models.BodyStructure, error) {
	var body models.BodyStructure
	contentType, ctParams, err := e.Header.ContentType()
	if err != nil {
		return nil, fmt.Errorf("could not parse content type: %v", err)
	}
	mimeType, mimeSubType := splitMIME(contentType)
	body.MIMEType = mimeType
	body.MIMESubType = mimeSubType
	body.Params = ctParams
	body.Description = e.Header.Get("content-description")
	body.Encoding = e.Header.Get("content-transfer-encoding")
	if cd := e.Header.Get("content-disposition"); cd != "" {
		contentDisposition, cdParams, err := e.Header.ContentDisposition()
		if err != nil {
			return nil, fmt.Errorf("could not parse content disposition: %v", err)
		}
		body.Disposition = contentDisposition
		body.DispositionParams = cdParams
	}
	body.Parts = []*models.BodyStructure{}
	if mpr := e.MultipartReader(); mpr != nil {
		for {
			part, err := mpr.NextPart()
			if err == io.EOF {
				return &body, nil
			} else if err != nil {
				return nil, err
			}
			ps, err := ParseEntityStructure(part)
			if err != nil {
				return nil, fmt.Errorf("could not parse child entity structure: %v", err)
			}
			body.Parts = append(body.Parts, ps)
		}
	}
	return &body, nil
}

func parseEnvelope(h *mail.Header) (*models.Envelope, error) {
	date, err := parseDate(h)
	if err != nil {
		return nil, fmt.Errorf("could not parse date header: %v", err)
	}
	from, err := parseAddressList(h, "from")
	if err != nil {
		return nil, fmt.Errorf("could not read from address: %v", err)
	}
	to, err := parseAddressList(h, "to")
	if err != nil {
		return nil, fmt.Errorf("could not read to address: %v", err)
	}
	cc, err := parseAddressList(h, "cc")
	if err != nil {
		return nil, fmt.Errorf("could not read cc address: %v", err)
	}
	bcc, err := parseAddressList(h, "bcc")
	if err != nil {
		return nil, fmt.Errorf("could not read bcc address: %v", err)
	}
	replyTo, err := parseAddressList(h, "reply-to")
	if err != nil {
		return nil, fmt.Errorf("could not read reply-to address: %v", err)
	}
	subj, err := h.Subject()
	if err != nil {
		return nil, fmt.Errorf("could not read subject: %v", err)
	}
	msgID, err := h.Text("message-id")
	if err != nil {
		return nil, fmt.Errorf("could not read message id: %v", err)
	}
	return &models.Envelope{
		Date:      date,
		Subject:   subj,
		MessageId: msgID,
		From:      from,
		ReplyTo:   replyTo,
		To:        to,
		Cc:        cc,
		Bcc:       bcc,
	}, nil
}

// parseDate extends the built-in date parser with additional layouts which are
// non-conforming but appear in the wild.
func parseDate(h *mail.Header) (time.Time, error) {
	t, parseErr := h.Date()
	if parseErr == nil {
		return t, nil
	}
	text, err := h.Text("date")
	if err != nil {
		return time.Time{}, errors.New("no date header")
	}
	// sometimes, no error occurs but the date is empty. In this case, guess time from received header field
	if text == "" {
		guess, err := h.Text("received")
		if err != nil {
			return time.Time{}, errors.New("no received header")
		}
		t, _ := time.Parse(time.RFC1123Z, dateRe.FindString(guess))
		return t, nil
	}
	layouts := []string{
		// X-Mailer: EarthLink Zoo Mail 1.0
		"Mon, _2 Jan 2006 15:04:05 -0700 (GMT-07:00)",
	}
	for _, layout := range layouts {
		if t, err := time.Parse(layout, text); err == nil {
			return t, nil
		}
	}
	return time.Time{}, fmt.Errorf("unrecognized date format: %s", text)
}

func parseAddressList(h *mail.Header, key string) ([]*models.Address, error) {
	var converted []*models.Address
	addrs, err := h.AddressList(key)
	if err != nil {
		if hdr, err := h.Text(key); err == nil {
			return []*models.Address{&models.Address{
				Name: hdr,
			}}, nil
		}
		return nil, err
	}
	for _, addr := range addrs {
		parts := strings.Split(addr.Address, "@")
		var mbox, host string
		if len(parts) > 1 {
			mbox = strings.Join(parts[0:len(parts)-1], "@")
			host = parts[len(parts)-1]
		} else {
			mbox = addr.Address
		}
		converted = append(converted, &models.Address{
			Name:    addr.Name,
			Mailbox: mbox,
			Host:    host,
		})
	}
	return converted, nil
}

// RawMessage is an interface that describes a raw message
type RawMessage interface {
	NewReader() (io.Reader, error)
	ModelFlags() ([]models.Flag, error)
	Labels() ([]string, error)
	UID() uint32
}

// MessageInfo populates a models.MessageInfo struct for the message.
// based on the reader returned by NewReader
func MessageInfo(raw RawMessage) (*models.MessageInfo, error) {
	r, err := raw.NewReader()
	if err != nil {
		return nil, err
	}
	msg, err := message.Read(r)
	if err != nil {
		return nil, fmt.Errorf("could not read message: %v", err)
	}
	bs, err := ParseEntityStructure(msg)
	if err != nil {
		return nil, fmt.Errorf("could not get structure: %v", err)
	}
	env, err := parseEnvelope(&mail.Header{msg.Header})
	if err != nil {
		return nil, fmt.Errorf("could not get envelope: %v", err)
	}
	flags, err := raw.ModelFlags()
	if err != nil {
		return nil, err
	}
	labels, err := raw.Labels()
	if err != nil {
		return nil, err
	}
	return &models.MessageInfo{
		BodyStructure: bs,
		Envelope:      env,
		Flags:         flags,
		Labels:        labels,
		InternalDate:  env.Date,
		RFC822Headers: &mail.Header{msg.Header},
		Size:          0,
		Uid:           raw.UID(),
	}, nil
}