use textproto package to parse the content-type found

scanner.go

@@ -12,6 +12,8 @@ import (
 	"errors"
 	"io"
 	"net/mail"
+	"net/textproto"
+	"strings"
 )
 
 // ErrInvalidMboxFormat is the error returned by the Next method of type Mbox if
@@ -34,25 +36,6 @@ func scanMessage(data []byte, atEOF bool) (int, []byte, error) {
 		advanceExtra = 1
 		e = bytes.Index(data, []byte("\nFrom "))
 	}
-	if e > 0 {
-		if ctStart := bytes.Index(data[:e+1], []byte(boundarySep)); ctStart != -1 {
-			if ctEnd := bytes.Index(data[ctStart+len(boundarySep):], []byte("\"")); ctEnd != -1 {
-				//log.Printf("ctStart = %d, ctEnd = %d", ctStart, ctEnd)
-				boundary := []byte("\n--" + string(data[ctStart+len(boundarySep):ctStart+len(boundarySep)+ctEnd]) + "--\n")
-				//log.Printf("Looking for boundary -- %q", boundary)
-				if boundEnd := bytes.Index(data, boundary); boundEnd == -1 {
-					//log.Printf("Asking for more!")
-					return 0, nil, nil // ask for more!  We don't see the end boundary yet
-				} else {
-					e = bytes.Index(data[boundEnd:], []byte("\nFrom "))
-					if e != -1 {
-						e += boundEnd
-					}
-					//log.Printf("oldE = %d, newE = %d", oldE, e)
-				}
-			}
-		}
-	}
 	if e == -1 && !atEOF {
 		// request more data
 		return advanceExtra, nil, nil
@@ -72,14 +55,39 @@ func scanMessage(data []byte, atEOF bool) (int, []byte, error) {
 		}
 		return len(data) + advanceExtra, data[n+1:], nil
 	}
+	tpr := textproto.NewReader(bufio.NewReader(bytes.NewReader(data[n+1:])))
+	header, err := tpr.ReadMIMEHeader()
+	if err != nil {
+		return 0, nil, err
+	}
+	cth := header.Get("Content-Type")
+	boundaryEnd := ""
+	if strings.Contains(cth, "multipart") {
+		splt := strings.Split(cth, "; ")
+		for _, v := range splt {
+			if strings.HasPrefix(v, "boundary=") {
+				c := strings.Index(v, "=") + 1
+				boundaryEnd = "--" + strings.Trim(v[c:], `"'`) + "--"
+				break
+			}
+		}
+	}
+	if boundaryEnd != "" {
+		b := bytes.Index(data, []byte(boundaryEnd))
+		if b == -1 {
+			return 0, nil, nil // need more data!
+		}
+		if e < b {
+			e = bytes.Index(data[b:], []byte("\nFrom "))
+			e += b
+		}
+	}
 	if data[e-1] != '\n' {
 		return e + 1 + advanceExtra, data[n+1 : e+1], nil
 	}
 	return e + 1 + advanceExtra, data[n+1 : e], nil
 }
 
-const boundarySep = "Content-Type: multipart/alternative; boundary=\""
-
 // Scanner provides an interface to read a sequence of messages from an mbox.
 // Calling the Next method steps through the messages. The current message can
 // then be accessed by calling the Message method.

scanner_test.go

@@ -431,7 +431,8 @@ From one place.
 From: herp.derp at example.com (Herp Derp)
 Date: Thu, 01 Jan 2015 00:00:01 +0100
 Subject: Test
-Content-Type: multipart/alternative; boundary="_----------=bestboundaryever"
+Content-Type: multipart/alternative;
+        boundary=Apple-Mail-D55D9B1A-A379-4D5C-BDA9-00D35DF424A0
 
 This is a test of boundaries.  Don't accept a new email via \nFrom until the boundary is done!'
 
@@ -441,7 +442,7 @@ From Herp Derp with love.
 From Herp Derp with love.
 
 Bye.
---_----------=bestboundaryever--
+--Apple-Mail-D55D9B1A-A379-4D5C-BDA9-00D35DF424A0--
 
 From another!
 From: herp.derp at example.com (Herp Derp)
@@ -451,7 +452,77 @@ Subject: Test
 This is the second email in a test of boundaries.
 `
 	expected := []string{
-		"This is a test of boundaries.  Don't accept a new email via \\nFrom until the boundary is done!'\n\nAnd, by the way, this is how a \"From\" line is escaped in mboxo format:\nFrom Herp Derp with love.\n\nFrom Herp Derp with love.\n\nBye.\n--_----------=bestboundaryever--\n",
+		"This is a test of boundaries.  Don't accept a new email via \\nFrom until the boundary is done!'\n\nAnd, by the way, this is how a \"From\" line is escaped in mboxo format:\nFrom Herp Derp with love.\n\nFrom Herp Derp with love.\n\nBye.\n--Apple-Mail-D55D9B1A-A379-4D5C-BDA9-00D35DF424A0--\n",
+		"This is the second email in a test of boundaries.\n",
+	}
+	b := bytes.NewBufferString(sourceData)
+	m := NewScanner(b)
+
+	for i := range expected {
+		if !m.Next() {
+			t.Errorf("Next() failed; pass %d", i)
+		}
+		if m.Err() != nil {
+			t.Errorf("Unexpected error after Next(): %v", m.Err())
+		}
+
+		msg := m.Message()
+		if msg == nil {
+			t.Errorf("message is nil; pass %d", i)
+			continue
+		}
+		body := new(bytes.Buffer)
+		_, err := body.ReadFrom(msg.Body)
+		if err != nil {
+			t.Errorf("%d - Unexpected error reading message body: %v", i, err)
+			continue
+		}
+		if body.String() != expected[i] {
+			t.Errorf("%d - Expected:\n %q\ngot\n%q", i, expected[i], body.String())
+		}
+		if m.Err() != nil {
+			t.Errorf("%d - Unexpected error after Message(): %v", i, m.Err())
+		}
+	}
+
+	if m.Next() {
+		t.Errorf("Next() succeeded")
+	}
+	if m.Err() != nil {
+		t.Errorf("Unexpected error after Next(): %v", m.Err())
+	}
+	if msg := m.Message(); msg != nil {
+		t.Errorf("message is not nil")
+	}
+	if m.Err() != nil {
+		t.Errorf("Unexpected error after Message(): %v", m.Err())
+	}
+}
+
+func TestScanMessageWithTextBoundary(t *testing.T) {
+	sourceData := `
+From one place.
+From: herp.derp at example.com (Herp Derp)
+Date: Thu, 01 Jan 2015 00:00:01 +0100
+Subject: Test
+Content-Type: text/html; charset="utf-8";
+ boundary="monkey_d3df4dc8-da5e-47dd-be15-f19c5ed55194"
+
+This is a test of boundaries.  Don't accept a new email via \nFrom until the boundary is done!'
+
+And, by the way, this is how a "From" line is escaped in mboxo format:
+
+Bye.
+
+From another!
+From: herp.derp at example.com (Herp Derp)
+Date: Thu, 01 Jan 2015 00:00:01 +0100
+Subject: Test
+
+This is the second email in a test of boundaries.
+`
+	expected := []string{
+		"This is a test of boundaries.  Don't accept a new email via \\nFrom until the boundary is done!'\n\nAnd, by the way, this is how a \"From\" line is escaped in mboxo format:\n\nBye.\n",
 		"This is the second email in a test of boundaries.\n",
 	}
 	b := bytes.NewBufferString(sourceData)