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imapclient: fix parsing of BODYSTRUCTURE responses from Dovecot for message/global #704

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imapclient: fix parsing of BODYSTRUCTURE responses from Dovecot for message/global #704

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6 changes: 5 additions & 1 deletion imapclient/fetch.go
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Original file line number Diff line number Diff line change
Expand Up @@ -990,7 +990,11 @@ func readBodyType1part(dec *imapwire.Decoder, typ string, options *Options) (*im
return &bs, nil
}

if strings.EqualFold(bs.Type, "message") && (strings.EqualFold(bs.Subtype, "rfc822") || strings.EqualFold(bs.Subtype, "global")) {
// If the Content-Type is message/rfc822, the envelope, body structure, and number of
// lines must come next. If it's message/global, IMAP4rev2 servers will include them,
// but IMAP4rev1 servers may not. So in that case, we can go by whether the next byte
// is '(', since the envelope is a parenthesized list.
if strings.EqualFold(bs.Type, "message") && (strings.EqualFold(bs.Subtype, "rfc822") || strings.EqualFold(bs.Subtype, "global") && dec.NextByteIs('(')) {
var msg imap.BodyStructureMessageRFC822

msg.Envelope, err = readEnvelope(dec, options)
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211 changes: 211 additions & 0 deletions imapclient/parse_test.go
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Original file line number Diff line number Diff line change
@@ -0,0 +1,211 @@
package imapclient

import (
"bufio"
"encoding/json"
"reflect"
"strings"
"testing"

"github.com/emersion/go-imap/v2"
"github.com/emersion/go-imap/v2/internal/imapwire"
)

var bodyStructureCases = []struct {
description string
data string
parsed imap.BodyStructure
}{
{
description: "example from RFC 3501",
data: `(("TEXT" "PLAIN" ("CHARSET" "US-ASCII") NIL NIL "7BIT" 1152 23)("TEXT" "PLAIN" ("CHARSET" "US-ASCII" "NAME" "cc.diff") "<[email protected]>" "Compiler diff" "BASE64" 4554 73) "MIXED") `,
parsed: &imap.BodyStructureMultiPart{
Children: []imap.BodyStructure{
&imap.BodyStructureSinglePart{
Type: "TEXT",
Subtype: "PLAIN",
Params: map[string]string{"charset": "US-ASCII"},
ID: "",
Description: "",
Encoding: "7BIT",
Size: 1152,
Text: &imap.BodyStructureText{
NumLines: 23,
},
},
&imap.BodyStructureSinglePart{
Type: "TEXT",
Subtype: "PLAIN",
Params: map[string]string{
"charset": "US-ASCII",
"name": "cc.diff",
},
ID: "<[email protected]>",
Description: "Compiler diff",
Encoding: "BASE64",
Size: 4554,
Text: &imap.BodyStructureText{
NumLines: 73,
},
},
},
Subtype: "MIXED",
},
},
{
description: "issue #678",
data: `("text" "html" ("charset" "utf-8") NIL NIL "quoted-printable" 5606 133 NIL NIL NIL NIL)`,
parsed: &imap.BodyStructureSinglePart{
Type: "text",
Subtype: "html",
Params: map[string]string{"charset": "utf-8"},
ID: "",
Description: "",
Encoding: "quoted-printable",
Size: 5606,
Text: &imap.BodyStructureText{
NumLines: 133,
},
Extended: &imap.BodyStructureSinglePartExt{},
},
},
{
description: "message/global attachment in Dovecot",
data: `(((("text" "plain" ("charset" "UTF-8") NIL NIL "quoted-printable" 576 31 NIL NIL NIL NIL)("text" "html" ("charset" "UTF-8") NIL NIL "quoted-printable" 4691 112 NIL NIL NIL NIL) "alternative" ("boundary" "----=_NextPart_002_0063_01D85E63.43189F50") NIL NIL NIL)("image" "png" ("name" "image001.png") "<[email protected]>" NIL "base64" 3832 NIL NIL NIL NIL) "related" ("boundary" "----=_NextPart_001_0062_01D85E63.43189F50") NIL NIL NIL)("message" "delivery-status" ("name" "details.txt") NIL NIL "7bit" 594 NIL ("attachment" ("filename" "details.txt")) NIL NIL)("message" "global" ("name" "Untitled attachment 00019.dat") NIL NIL "7bit" 6726 NIL ("attachment" ("filename" "Untitled attachment 00019.dat")) NIL NIL) "mixed" ("boundary" "----=_NextPart_000_0061_01D85E63.43189F50") NIL ("en-us") NIL)`,
parsed: &imap.BodyStructureMultiPart{
Children: []imap.BodyStructure{
&imap.BodyStructureMultiPart{
Children: []imap.BodyStructure{
&imap.BodyStructureMultiPart{
Children: []imap.BodyStructure{
&imap.BodyStructureSinglePart{
Type: "text",
Subtype: "plain",
Params: map[string]string{
"charset": "UTF-8",
},
ID: "",
Description: "",
Encoding: "quoted-printable",
Size: 576,
Text: &imap.BodyStructureText{
NumLines: 31,
},
Extended: &imap.BodyStructureSinglePartExt{},
},
&imap.BodyStructureSinglePart{
Type: "text",
Subtype: "html",
Params: map[string]string{
"charset": "UTF-8",
},
ID: "",
Description: "",
Encoding: "quoted-printable",
Size: 4691,
Text: &imap.BodyStructureText{
NumLines: 112,
},
Extended: &imap.BodyStructureSinglePartExt{},
},
},
Subtype: "alternative",
Extended: &imap.BodyStructureMultiPartExt{
Params: map[string]string{
"boundary": "----=_NextPart_002_0063_01D85E63.43189F50",
},
},
},
&imap.BodyStructureSinglePart{
Type: "image",
Subtype: "png",
Params: map[string]string{
"name": "image001.png",
},
ID: "<[email protected]>",
Description: "",
Encoding: "base64",
Size: 3832,
Extended: &imap.BodyStructureSinglePartExt{},
},
},
Subtype: "related",
Extended: &imap.BodyStructureMultiPartExt{
Params: map[string]string{
"boundary": "----=_NextPart_001_0062_01D85E63.43189F50",
},
},
},
&imap.BodyStructureSinglePart{
Type: "message",
Subtype: "delivery-status",
Params: map[string]string{
"name": "details.txt",
},
ID: "",
Description: "",
Encoding: "7bit",
Size: 594,
Extended: &imap.BodyStructureSinglePartExt{
Disposition: &imap.BodyStructureDisposition{
Value: "attachment",
Params: map[string]string{
"filename": "details.txt",
},
},
},
},
&imap.BodyStructureSinglePart{
Type: "message",
Subtype: "global",
Params: map[string]string{
"name": "Untitled attachment 00019.dat",
},
ID: "",
Description: "",
Encoding: "7bit",
Size: 6726,
MessageRFC822: nil,
Extended: &imap.BodyStructureSinglePartExt{
Disposition: &imap.BodyStructureDisposition{
Value: "attachment",
Params: map[string]string{
"filename": "Untitled attachment 00019.dat",
},
},
},
},
},
Subtype: "mixed",
Extended: &imap.BodyStructureMultiPartExt{
Params: map[string]string{
"boundary": "----=_NextPart_000_0061_01D85E63.43189F50",
},
Language: []string{
"en-us",
},
},
},
},
}

func TestParseBodyStructure(t *testing.T) {
for _, c := range bodyStructureCases {
dec := imapwire.NewDecoder(bufio.NewReader(strings.NewReader(c.data)), imapwire.ConnSideClient)
s, err := readBody(dec, &Options{})
if err != nil {
t.Fatalf("%s: error parsing body structure: %v", c.description, err)
}
if !reflect.DeepEqual(s, c.parsed) {
t.Fatalf("%s: parsed structure doesn't match: want %s, got %s", c.description, toJSON(c.parsed), toJSON(s))
}
}
}

func toJSON(v any) []byte {
data, err := json.Marshal(v)
if err != nil {
panic(err)
}
return data
}
8 changes: 8 additions & 0 deletions internal/imapwire/decoder.go
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Original file line number Diff line number Diff line change
Expand Up @@ -122,6 +122,14 @@ func (dec *Decoder) acceptByte(want byte) bool {
return true
}

func (dec *Decoder) NextByteIs(want byte) bool {
if dec.acceptByte(want) {
dec.mustUnreadByte()
return true
}
return false
}

// EOF returns true if end-of-file is reached.
func (dec *Decoder) EOF() bool {
_, err := dec.r.ReadByte()
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