package imap
import (
"encoding/base64"
"strings"
"testing"
)
func TestExtractAttachments_plainAttachment(t *testing.T) {
pdfData := []byte("%PDF-1.4\n")
raw := buildMultipartMessage(t, "mixed", []mimePart{
{
contentType: "text/plain",
body: []byte("Hello world"),
},
{
contentType: "application/pdf; name=\"doc.pdf\"",
disposition: "attachment; filename=\"doc.pdf\"",
body: pdfData,
transferEnc: "base64",
},
})
attachments, err := ExtractAttachments(raw)
if err != nil {
t.Fatalf("ExtractAttachments() error = %v", err)
}
if len(attachments) != 1 {
t.Fatalf("len(attachments) = %d, want 1", len(attachments))
}
att := attachments[0]
if att.Filename != "doc.pdf" {
t.Fatalf("Filename = %q, want doc.pdf", att.Filename)
}
if att.ContentType != "application/pdf" {
t.Fatalf("ContentType = %q, want application/pdf", att.ContentType)
}
if att.IsInline {
t.Fatal("IsInline = true, want false")
}
if att.ContentID != "" {
t.Fatalf("ContentID = %q, want empty", att.ContentID)
}
if string(att.Data) != string(pdfData) {
t.Fatalf("Data = %q, want %q", att.Data, pdfData)
}
}
func TestExtractAttachments_inlineWithCID(t *testing.T) {
pngData := []byte{0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n'}
raw := buildMultipartMessage(t, "related", []mimePart{
{
contentType: "text/html",
body: []byte(`
`),
},
{
contentType: "image/png; name=\"logo.png\"",
disposition: "inline; filename=\"logo.png\"",
contentID: "",
body: pngData,
transferEnc: "base64",
},
})
attachments, err := ExtractAttachments(raw)
if err != nil {
t.Fatalf("ExtractAttachments() error = %v", err)
}
if len(attachments) != 1 {
t.Fatalf("len(attachments) = %d, want 1", len(attachments))
}
att := attachments[0]
if att.Filename != "logo.png" {
t.Fatalf("Filename = %q, want logo.png", att.Filename)
}
if att.ContentType != "image/png" {
t.Fatalf("ContentType = %q, want image/png", att.ContentType)
}
if !att.IsInline {
t.Fatal("IsInline = false, want true")
}
if att.ContentID != "logo@cid" {
t.Fatalf("ContentID = %q, want logo@cid", att.ContentID)
}
if string(att.Data) != string(pngData) {
t.Fatalf("Data = %q, want %q", att.Data, pngData)
}
}
func TestExtractAttachments_inlineCIDWithoutFilename(t *testing.T) {
pngData := []byte{0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n'}
raw := buildMultipartMessage(t, "related", []mimePart{
{
contentType: "text/html",
body: []byte(`
`),
},
{
contentType: "image/png",
disposition: "inline",
contentID: "",
body: pngData,
transferEnc: "base64",
},
})
attachments, err := ExtractAttachments(raw)
if err != nil {
t.Fatalf("ExtractAttachments() error = %v", err)
}
if len(attachments) != 1 {
t.Fatalf("len(attachments) = %d, want 1", len(attachments))
}
att := attachments[0]
if att.ContentID != "part1" {
t.Fatalf("ContentID = %q, want part1", att.ContentID)
}
if !att.IsInline {
t.Fatal("IsInline = false, want true")
}
if att.Filename == "" {
t.Fatal("Filename empty, want generated name")
}
if string(att.Data) != string(pngData) {
t.Fatalf("Data mismatch")
}
}
func TestExtractAttachments_nestedMixedRelatedInline(t *testing.T) {
pngData := []byte{0x89, 'P', 'N', 'G', '\r', '\n', 0x1a, '\n'}
pdfData := []byte("%PDF-1.4\n")
raw := []byte(
"From: ikea@example.com\r\n" +
"To: user@example.com\r\n" +
"Subject: ticket\r\n" +
"MIME-Version: 1.0\r\n" +
"Content-Type: multipart/mixed; boundary=\"mix\"\r\n" +
"\r\n" +
"--mix\r\n" +
"Content-Type: multipart/related; boundary=\"rel\"\r\n" +
"\r\n" +
"--rel\r\n" +
"Content-Type: multipart/alternative; boundary=\"alt\"\r\n" +
"\r\n" +
"--alt\r\n" +
"Content-Type: text/plain\r\n" +
"\r\n" +
"Merci pour votre achat\r\n" +
"--alt\r\n" +
"Content-Type: text/html\r\n" +
"\r\n" +
"![\"Logo\"](\"cid:Color.png\")
\r\n" +
"--alt--\r\n" +
"--rel\r\n" +
"Content-Type: image/png; name=\"Color.png\"\r\n" +
"Content-Transfer-Encoding: base64\r\n" +
"Content-ID: \r\n" +
"Content-Disposition: inline; filename=\"Color.png\"\r\n" +
"\r\n" +
base64.StdEncoding.EncodeToString(pngData) + "\r\n" +
"--rel--\r\n" +
"--mix\r\n" +
"Content-Type: application/pdf; name=\"ticket.pdf\"\r\n" +
"Content-Transfer-Encoding: base64\r\n" +
"Content-Disposition: attachment; filename=\"ticket.pdf\"\r\n" +
"\r\n" +
base64.StdEncoding.EncodeToString(pdfData) + "\r\n" +
"--mix--\r\n",
)
attachments, err := ExtractAttachments(raw)
if err != nil {
t.Fatalf("ExtractAttachments() error = %v", err)
}
if len(attachments) != 2 {
t.Fatalf("len(attachments) = %d, want 2 (inline png + pdf)", len(attachments))
}
var inlineFound, pdfFound bool
for _, att := range attachments {
switch {
case att.IsInline && att.ContentID == "Color.png":
inlineFound = true
case !att.IsInline && att.Filename == "ticket.pdf":
pdfFound = true
}
}
if !inlineFound {
t.Fatal("inline Color.png attachment missing")
}
if !pdfFound {
t.Fatal("pdf attachment missing")
}
}
func TestExtractAttachments_skipsBodyParts(t *testing.T) {
raw := buildMultipartMessage(t, "alternative", []mimePart{
{
contentType: "text/plain",
body: []byte("plain body"),
},
{
contentType: "text/html",
body: []byte("html body
"),
},
})
attachments, err := ExtractAttachments(raw)
if err != nil {
t.Fatalf("ExtractAttachments() error = %v", err)
}
if len(attachments) != 0 {
t.Fatalf("len(attachments) = %d, want 0", len(attachments))
}
}
type mimePart struct {
contentType string
disposition string
contentID string
transferEnc string
body []byte
}
func buildMultipartMessage(t *testing.T, subtype string, parts []mimePart) []byte {
t.Helper()
const boundary = "test-boundary"
var b strings.Builder
b.WriteString("From: sender@example.com\r\n")
b.WriteString("To: recipient@example.com\r\n")
b.WriteString("Subject: attachment test\r\n")
b.WriteString("MIME-Version: 1.0\r\n")
b.WriteString("Content-Type: multipart/" + subtype + "; boundary=\"" + boundary + "\"\r\n")
b.WriteString("\r\n")
for _, part := range parts {
b.WriteString("--" + boundary + "\r\n")
b.WriteString("Content-Type: " + part.contentType + "\r\n")
if part.disposition != "" {
b.WriteString("Content-Disposition: " + part.disposition + "\r\n")
}
if part.contentID != "" {
b.WriteString("Content-ID: " + part.contentID + "\r\n")
}
if part.transferEnc != "" {
b.WriteString("Content-Transfer-Encoding: " + part.transferEnc + "\r\n")
}
b.WriteString("\r\n")
if part.transferEnc == "base64" {
b.WriteString(base64.StdEncoding.EncodeToString(part.body))
} else {
b.Write(part.body)
}
b.WriteString("\r\n")
}
b.WriteString("--" + boundary + "--\r\n")
return []byte(b.String())
}