Parse MIME parts into a node tree

app/inbucket/mime.go

@@ -7,6 +7,7 @@ import (
 	"mime"
 	"mime/multipart"
 	"net/mail"
+	"os"
 )
 
 const MIME_BUF_BYTES = 1024
@@ -16,6 +17,30 @@ type MIMEMessage struct {
 	html string
 }
 
+type MIMENode struct {
+	Parent      *MIMENode
+	FirstChild  *MIMENode
+	NextSibling *MIMENode
+	Type        string
+	Content     *bytes.Buffer
+}
+
+func NewMIMENode(parent *MIMENode, contentType string) *MIMENode {
+	return &MIMENode{Parent: parent, Type: contentType}
+}
+
+func (n *MIMENode) String() string {
+	children := ""
+	siblings := ""
+	if n.FirstChild != nil {
+		children = n.FirstChild.String()
+	}
+	if n.NextSibling != nil {
+		siblings = n.NextSibling.String()
+	}
+	return fmt.Sprintf("[%v %v] %v", n.Type, children, siblings)
+}
+
 func ParseMIMEMessage(mailMsg *mail.Message) (*MIMEMessage, error) {
 	mimeMsg := new(MIMEMessage)
 
@@ -36,11 +61,19 @@ func ParseMIMEMessage(mailMsg *mail.Message) (*MIMEMessage, error) {
 		return nil, fmt.Errorf("Unable to locate boundary param in Content-Type header")
 	}
 
-	// Buffer used by Part.Read to hand us chunks of data
-	readBytes := make([]byte, MIME_BUF_BYTES)
+	// Root Node of our tree
+	root := NewMIMENode(nil, mediatype)
+
+	err = parseNodes(root, mailMsg.Body, boundary)
+	fmt.Println(root.String())
+	return mimeMsg, err
+}
+
+func parseNodes(parent *MIMENode, reader io.Reader, boundary string) error {
+	var prevSibling *MIMENode
 
 	// Loop over MIME parts
-	mr := multipart.NewReader(mailMsg.Body, boundary)
+	mr := multipart.NewReader(reader, boundary)
 	for {
 		part, err := mr.NextPart()
 		if err != nil {
@@ -48,34 +81,41 @@ func ParseMIMEMessage(mailMsg *mail.Message) (*MIMEMessage, error) {
 				// This is a clean end-of-message signal
 				break
 			}
-			return nil, err
+			return err
 		}
-		mediatype, params, err = mime.ParseMediaType(part.Header.Get("Content-Type"))
+		mediatype, params, err := mime.ParseMediaType(part.Header.Get("Content-Type"))
 		if err != nil {
-			return nil, err
+			return err
 		}
-		if mediatype == "text/plain" && mimeMsg.text == "" {
-			// First text section, we'll have that, but first we have to deal with
-			// the odd way Part lets us read data.
-			var buf bytes.Buffer
-			for {
-				n, err := part.Read(readBytes)
-				if err != nil {
-					if err == io.EOF {
-						// Clean end of part signal
-						break
-					}
-					return nil, err
-				}
-				// Extra data in readBytes is not cleared, so we must respect
-				// the value returned in 'n'
-				buf.Write(readBytes[:n])
-			}
 
-			mimeMsg.text = buf.String()
-			fmt.Printf("text: '%v'\n", mimeMsg.text)
+		// Insert ourselves into tree
+		node := NewMIMENode(parent, mediatype)
+		if prevSibling != nil {
+			prevSibling.NextSibling = node
+		} else {
+			parent.FirstChild = node
+		}
+		prevSibling = node
+
+		boundary := params["boundary"]
+		if boundary != "" {
+			// Content is another multipart
+			err = parseNodes(node, part, boundary)
+			if err != nil {
+				return err
+			}
+		} else {
+			// Content is data, allocate a buffer
+			node.Content = new(bytes.Buffer)
+			_, err = io.Copy(node.Content, part)
+			if err != nil {
+				return err
+			}
+			fmt.Printf("\n----\n")
+			io.Copy(os.Stdout, node.Content)
+			fmt.Printf("\n----\n")
 		}
 	}
 
-	return mimeMsg, nil
+	return nil
 }