Improved message rendering

Added a decodeSection function to mime.go that uses go-qprintable to
parse quoted-printable emails or MIME parts, fixes #7

Added a very basic TextToHtml converter to provide nicer rending of text
message bodies.

app/controllers/mailbox.go

@@ -69,7 +69,7 @@ func (c Mailbox) Show(name string, id string) rev.Result {
 	if err != nil {
 		return c.RenderError(err)
 	}
-	body := mime.Text
+	body := template.HTML(inbucket.TextToHtml(mime.Text))
 	htmlAvailable := mime.Html != ""
 
 	c.Response.Out.Header().Set("Expires", "-1")

app/inbucket/mime.go

@@ -4,11 +4,12 @@ import (
 	"bytes"
 	"container/list"
 	"fmt"
+	"github.com/sloonz/go-qprintable"
 	"io"
-	"io/ioutil"
 	"mime"
 	"mime/multipart"
 	"net/mail"
+	"strings"
 )
 
 type MIMENodeMatcher func(node *MIMENode) bool
@@ -85,7 +86,7 @@ func ParseMIMEBody(mailMsg *mail.Message) (*MIMEBody, error) {
 
 	if !IsMIMEMessage(mailMsg) {
 		// Parse as text only
-		bodyBytes, err := ioutil.ReadAll(mailMsg.Body)
+		bodyBytes, err := decodeSection(mailMsg.Header.Get("Content-Transfer-Encoding"), mailMsg.Body)
 		if err != nil {
 			return nil, err
 		}
@@ -136,6 +137,29 @@ func (m *MIMEBody) String() string {
 	return fmt.Sprintf("----TEXT----\n%v\n----HTML----\n%v\n----END----\n", m.Text, m.Html)
 }
 
+// decodeSection attempts to decode the data from reader using the algorithm listed in
+// the Content-Transfer-Encoding header, returning the raw data if it does not know
+// the encoding type.
+func decodeSection(encoding string, reader io.Reader) ([]byte, error) {
+	switch strings.ToLower(encoding) {
+	case "quoted-printable":
+		decoder := qprintable.NewDecoder(qprintable.WindowsTextEncoding, reader)
+		buf := new(bytes.Buffer)
+		_, err := buf.ReadFrom(decoder)
+		if err != nil {
+			return nil, err
+		}
+		return buf.Bytes(), nil
+	}
+	// Don't know this type, just return bytes
+	buf := new(bytes.Buffer)
+	_, err := buf.ReadFrom(reader)
+	if err != nil {
+		return nil, err
+	}
+	return buf.Bytes(), nil
+}
+
 func parseNodes(parent *MIMENode, reader io.Reader, boundary string) error {
 	var prevSibling *MIMENode
 
@@ -172,13 +196,12 @@ func parseNodes(parent *MIMENode, reader io.Reader, boundary string) error {
 				return err
 			}
 		} else {
-			// Content is data, allocate a buffer
-			buf := new(bytes.Buffer)
-			_, err = buf.ReadFrom(part)
+			// Content is text or data, decode it
+			data, err := decodeSection(part.Header.Get("Content-Transfer-Encoding"), part)
 			if err != nil {
 				return err
 			}
-			node.Content = buf.Bytes()
+			node.Content = data
 		}
 	}
 

app/inbucket/mime_test.go

@@ -42,6 +42,28 @@ func TestParseInlineText(t *testing.T) {
 	assert.Equal(t, mime.Text, "Test of HTML section")
 }
 
+func TestParseQuotedPrintable(t *testing.T) {
+	msg := readMessage("quoted-printable.raw")
+
+	mime, err := ParseMIMEBody(msg)
+	if err != nil {
+		t.Fatalf("Failed to parse MIME: %v", err)
+	}
+
+	assert.Contains(t, mime.Text, "Phasellus sit amet arcu")
+}
+
+func TestParseQuotedPrintableMime(t *testing.T) {
+	msg := readMessage("quoted-printable-mime.raw")
+
+	mime, err := ParseMIMEBody(msg)
+	if err != nil {
+		t.Fatalf("Failed to parse MIME: %v", err)
+	}
+
+	assert.Contains(t, mime.Text, "Nullam venenatis ante")
+}
+
 func TestParseInlineHtml(t *testing.T) {
 	msg := readMessage("html-mime-inline.raw")
 

app/inbucket/utils.go

@@ -3,6 +3,7 @@ package inbucket
 import (
   "crypto/sha1"
   "fmt"
+  "html"
   "io"
   "strings"
 )
@@ -26,3 +27,11 @@ func HashMailboxName(mailbox string) string {
   return fmt.Sprintf("%x", h.Sum(nil))
 }
 
+// TextToHtml takes plain text, escapes it and tries to pretty it up for
+// HTML display
+func TextToHtml(text string) string {
+	text = html.EscapeString(text)
+	replacer := strings.NewReplacer("\r\n", "<br/>\n", "\r", "<br/>\n", "\n", "<br/>\n")
+	return replacer.Replace(text)
+}
+

app/inbucket/utils_test.go

@@ -1,28 +1,44 @@
 package inbucket
 
-import "testing"
+import (
+	"github.com/stretchrcom/testify/assert"
+	"testing"
+)
 
 func TestParseMailboxName(t *testing.T) {
-  in, out := "MailBOX", "mailbox"
-  if x := ParseMailboxName(in); x != out {
-    t.Errorf("ParseMailboxName(%v) = %v, want %v", in, x, out)
-  }
+	in, out := "MailBOX", "mailbox"
+	if x := ParseMailboxName(in); x != out {
+		t.Errorf("ParseMailboxName(%v) = %v, want %v", in, x, out)
+	}
 
-  in, out = "MailBox@Host.Com", "mailbox"
-  if x := ParseMailboxName(in); x != out {
-    t.Errorf("ParseMailboxName(%v) = %v, want %v", in, x, out)
-  }
+	in, out = "MailBox@Host.Com", "mailbox"
+	if x := ParseMailboxName(in); x != out {
+		t.Errorf("ParseMailboxName(%v) = %v, want %v", in, x, out)
+	}
 
-  in, out = "Mail+extra@Host.Com", "mail"
-  if x := ParseMailboxName(in); x != out {
-    t.Errorf("ParseMailboxName(%v) = %v, want %v", in, x, out)
-  }
+	in, out = "Mail+extra@Host.Com", "mail"
+	if x := ParseMailboxName(in); x != out {
+		t.Errorf("ParseMailboxName(%v) = %v, want %v", in, x, out)
+	}
 }
 
 func TestHashMailboxName(t *testing.T) {
-  in, out := "mail", "1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e"
-  if x := HashMailboxName(in); x != out {
-    t.Errorf("HashMailboxName(%v) = %v, want %v", in, x, out)
-  }
+	in, out := "mail", "1d6e1cf70ec6f9ab28d3ea4b27a49a77654d370e"
+	if x := HashMailboxName(in); x != out {
+		t.Errorf("HashMailboxName(%v) = %v, want %v", in, x, out)
+	}
+}
+
+func TestTextToHtml(t *testing.T) {
+	// Identity
+	assert.Equal(t, TextToHtml("html"), "html")
+
+	// Check it escapes
+	assert.Equal(t, TextToHtml("<html>"), "&lt;html&gt;")
+
+	// Check for linebreaks
+	assert.Equal(t, TextToHtml("line\nbreak"), "line<br/>\nbreak")
+	assert.Equal(t, TextToHtml("line\r\nbreak"), "line<br/>\nbreak")
+	assert.Equal(t, TextToHtml("line\rbreak"), "line<br/>\nbreak")
 }
 

app/views/Mailbox/Show.html

@@ -17,5 +17,5 @@
 <table>
 <div id="emailSubject"><h3>{{.message.Subject}}</h3></div>
 
-<pre id="emailBody">{{.body}}</pre>
+<div id="emailBody">{{.body}}</div>