Support for MIME headers when using NewEmailFromReader

.github/workflows/test.yml

@@ -11,6 +11,8 @@ jobs:
   build:
     name: Build
     runs-on: ubuntu-latest
+    env:
+      GO111MODULE: auto
     steps:
 
     - name: Set up Go 1.x

email.go

@@ -165,9 +165,9 @@ func NewEmailFromReader(r io.Reader) (*Email, error) {
 			if err != nil {
 				return e, err
 			}
-			filename, filenameDefined := params["filename"]
-			if cd == "attachment" || (cd == "inline" && filenameDefined) {
-				_, err = e.Attach(bytes.NewReader(p.body), filename, ct)
+			filename, _ := params["filename"]
+			if cd == "attachment" || (cd == "inline" && p.header.Get("Content-ID") != "") {
+				_, err = e.AttachWithHeaders(bytes.NewReader(p.body), filename, ct, p.header)
 				if err != nil {
 					return e, err
 				}
@@ -262,14 +262,21 @@ func parseMIMEParts(hs textproto.MIMEHeader, b io.Reader) ([]*part, error) {
 // Required parameters include an io.Reader, the desired filename for the attachment, and the Content-Type
 // The function will return the created Attachment for reference, as well as nil for the error, if successful.
 func (e *Email) Attach(r io.Reader, filename string, c string) (a *Attachment, err error) {
+	return e.AttachWithHeaders(r, filename, c, textproto.MIMEHeader{})
+}
+
+// AttachWithHeaders is used to attach content from an io.Reader to the email. Required parameters include an io.Reader,
+// the desired filename for the attachment, the Content-Type and the original MIME headers.
+// The function will return the created Attachment for reference, as well as nil for the error, if successful.
+func (e *Email) AttachWithHeaders(r io.Reader, filename string, c string, headers textproto.MIMEHeader) (a *Attachment, err error) {
 	var buffer bytes.Buffer
 	if _, err = io.Copy(&buffer, r); err != nil {
 		return
 	}
 	at := &Attachment{
 		Filename:    filename,
 		ContentType: c,
-		Header:      textproto.MIMEHeader{},
+		Header:      headers,
 		Content:     buffer.Bytes(),
 	}
 	e.Attachments = append(e.Attachments, at)
@@ -714,11 +721,11 @@ func (at *Attachment) setDefaultHeaders() {
 	at.Header.Set("Content-Type", contentType)
 
 	if len(at.Header.Get("Content-Disposition")) == 0 {
-		disposition := "attachment"
 		if at.HTMLRelated {
-			disposition = "inline"
+			at.Header.Set("Content-Disposition", "inline")
+		}else{
+			at.Header.Set("Content-Disposition", fmt.Sprintf("%s;\r\n filename=\"%s\"", "attachment", at.Filename))
 		}
-		at.Header.Set("Content-Disposition", fmt.Sprintf("%s;\r\n filename=\"%s\"", disposition, at.Filename))
 	}
 	if len(at.Header.Get("Content-ID")) == 0 {
 		at.Header.Set("Content-ID", fmt.Sprintf("<%s>", at.Filename))

email_test.go

@@ -85,6 +85,12 @@ func TestEmailWithHTMLAttachments(t *testing.T) {
 	}
 	attachment.HTMLRelated = true
 
+	// Set regular HTML attachment.
+	_, err = e.Attach(bytes.NewBufferString("Normal attachment"), "normal.pdf", "application/pdf; charset=utf-8")
+	if err != nil {
+		t.Fatal("Could not add an attachment to the message: ", err)
+	}
+
 	b, err := e.Bytes()
 	if err != nil {
 		t.Fatal("Could not serialize e-mail:", err)
@@ -110,14 +116,17 @@ func TestEmailWithHTMLAttachments(t *testing.T) {
 	plainTextFound := false
 	htmlFound := false
 	imageFound := false
-	if expected, actual := 3, len(ps); actual != expected {
+	if expected, actual := 4, len(ps); actual != expected {
 		t.Error("Unexpected number of parts. Expected:", expected, "Was:", actual)
 	}
 	for _, part := range ps {
 		// part has "header" and "body []byte"
 		cd := part.header.Get("Content-Disposition")
 		ct := part.header.Get("Content-Type")
-		if strings.Contains(ct, "image/png") && strings.HasPrefix(cd, "inline") {
+		if strings.Contains(ct, "image/png") && strings.HasPrefix(cd, "inline") && !strings.Contains(cd, "rad.txt"){
+			imageFound = true
+		}
+		if strings.Contains(ct, "application/pdf") && strings.HasPrefix(cd, "attachment") && strings.Contains(cd, "normal.pdf"){
 			imageFound = true
 		}
 		if strings.Contains(ct, "text/html") {
@@ -650,6 +659,11 @@ func TestAttachmentEmailFromReader(t *testing.T) {
 	if err != nil {
 		t.Fatalf("Error attaching inline image %s", err.Error())
 	}
+	c, err := ex.Attach(bytes.NewReader([]byte("Let's just pretend this is raw JPEG data.")), "html-related-cat.jpeg", "image/jpeg")
+	if err != nil {
+		t.Fatalf("Error attaching html-related inline image %s", err.Error())
+	}
+	b.HTMLRelated = true
 	raw := []byte(`
 From: Jordan Wright <jmwright798@gmail.com>
 Date: Thu, 17 Oct 2019 08:55:37 +0100
@@ -679,7 +693,7 @@ Content-Type: text/html; charset=UTF-8
 --35d10c2224bd787fe700c2c6f4769ddc936eb8a0b58e9c8717e406c5abb7
 Content-Disposition: attachment;
  filename="cat.jpeg"
-Content-Id: <cat.jpeg>
+Content-Id: <cat.content-id>
 Content-Transfer-Encoding: base64
 Content-Type: image/jpeg
 
@@ -688,7 +702,15 @@ TGV0J3MganVzdCBwcmV0ZW5kIHRoaXMgaXMgcmF3IEpQRUcgZGF0YS4=
 --35d10c2224bd787fe700c2c6f4769ddc936eb8a0b58e9c8717e406c5abb7
 Content-Disposition: inline;
  filename="cat-inline.jpeg"
-Content-Id: <cat-inline.jpeg>
+Content-Id: <cat-inline.content-id>
+Content-Transfer-Encoding: base64
+Content-Type: image/jpeg
+
+TGV0J3MganVzdCBwcmV0ZW5kIHRoaXMgaXMgcmF3IEpQRUcgZGF0YS4=
+
+--35d10c2224bd787fe700c2c6f4769ddc936eb8a0b58e9c8717e406c5abb7
+Content-Disposition: inline
+Content-Id: <html-related-cat.content-id>
 Content-Transfer-Encoding: base64
 Content-Type: image/jpeg
 
@@ -711,21 +733,43 @@ TGV0J3MganVzdCBwcmV0ZW5kIHRoaXMgaXMgcmF3IEpQRUcgZGF0YS4=
 	if e.From != ex.From {
 		t.Fatalf("Incorrect \"From\": %#q != %#q", e.From, ex.From)
 	}
-	if len(e.Attachments) != 2 {
-		t.Fatalf("Incorrect number of attachments %d != %d", len(e.Attachments), 1)
+	if len(e.Attachments) != 3 {
+		t.Fatalf("Incorrect number of attachments %d != %d", len(e.Attachments), 3)
 	}
 	if e.Attachments[0].Filename != a.Filename {
 		t.Fatalf("Incorrect attachment filename %s != %s", e.Attachments[0].Filename, a.Filename)
 	}
 	if !bytes.Equal(e.Attachments[0].Content, a.Content) {
 		t.Fatalf("Incorrect attachment content %#q != %#q", e.Attachments[0].Content, a.Content)
 	}
+	if e.Attachments[0].Header != nil {
+		if e.Attachments[0].Header.Get("Content-Id") != "<cat.content-id>" {
+			t.Fatalf("Incorrect attachment header Content-Id %s != %s", e.Attachments[0].Header.Get("Content-Id"), "<cat.content-id>")
+		}
+	}
 	if e.Attachments[1].Filename != b.Filename {
 		t.Fatalf("Incorrect attachment filename %s != %s", e.Attachments[1].Filename, b.Filename)
 	}
 	if !bytes.Equal(e.Attachments[1].Content, b.Content) {
 		t.Fatalf("Incorrect attachment content %#q != %#q", e.Attachments[1].Content, b.Content)
 	}
+	if e.Attachments[1].Header != nil {
+		if e.Attachments[1].Header.Get("Content-Id") != "<cat-inline.content-id>" {
+			t.Fatalf("Incorrect attachment header Content-Id %s != %s", e.Attachments[1].Header.Get("Content-Id"), "<cat-inline.content-id>")
+		}
+	}
+	//Filename should be empty as we are using html-related and inline attachment
+	if e.Attachments[2].Filename != "" {
+		t.Fatalf("Incorrect attachment filename %s != %s", e.Attachments[2].Filename, "")
+	}
+	if !bytes.Equal(e.Attachments[2].Content, c.Content) {
+		t.Fatalf("Incorrect attachment content %#q != %#q", e.Attachments[2].Content, c.Content)
+	}
+	if e.Attachments[2].Header != nil {
+		if e.Attachments[2].Header.Get("Content-Id") != "<html-related-cat.content-id>" {
+			t.Fatalf("Incorrect attachment header Content-Id %s != %s", e.Attachments[2].Header.Get("Content-Id"), "<html-related-cat.content-id>")
+		}
+	}
 }
 
 func ExampleGmail() {