Better mime type probing

server/server.go

@@ -150,9 +150,10 @@ var (
 )
 
 const (
-	firebaseControlTopic = "~control" // See Android if changed
-	emptyMessageBody     = "triggered"
-	fcmMessageLimit      = 4000 // see maybeTruncateFCMMessage for details
+	firebaseControlTopic     = "~control" // See Android if changed
+	emptyMessageBody         = "triggered"
+	fcmMessageLimit          = 4000 // see maybeTruncateFCMMessage for details
+	defaultAttachmentMessage = "You received a file: %s"
 )
 
 // New instantiates a new Server. It creates the cache and adds a Firebase
@@ -436,7 +437,7 @@ func (s *Server) handleFile(w http.ResponseWriter, r *http.Request, _ *visitor)
 		return err
 	}
 	defer f.Close()
-	_, err = io.Copy(util.NewContentTypeWriter(w), f)
+	_, err = io.Copy(util.NewContentTypeWriter(w, r.URL.Path), f)
 	return err
 }
 
@@ -609,6 +610,9 @@ func (s *Server) handleBodyAsMessage(m *message, body *util.PeakedReadCloser) er
 	if len(body.PeakedBytes) > 0 { // Empty body should not override message (publish via GET!)
 		m.Message = strings.TrimSpace(string(body.PeakedBytes)) // Truncates the message to the peak limit if required
 	}
+	if m.Attachment != nil && m.Attachment.Name != "" && m.Message == "" {
+		m.Message = fmt.Sprintf(defaultAttachmentMessage, m.Attachment.Name)
+	}
 	return nil
 }
 
@@ -622,16 +626,16 @@ func (s *Server) handleBodyAsAttachment(v *visitor, m *message, body *util.Peake
 		m.Attachment = &attachment{}
 	}
 	var err error
+	var ext string
 	m.Attachment.Owner = v.ip // Important for attachment rate limiting
 	m.Attachment.Expires = time.Now().Add(s.config.AttachmentExpiryDuration).Unix()
-	m.Attachment.Type = http.DetectContentType(body.PeakedBytes)
-	ext := util.ExtensionByType(m.Attachment.Type)
+	m.Attachment.Type, ext = util.DetectContentType(body.PeakedBytes, m.Attachment.Name)
 	m.Attachment.URL = fmt.Sprintf("%s/file/%s%s", s.config.BaseURL, m.ID, ext)
 	if m.Attachment.Name == "" {
 		m.Attachment.Name = fmt.Sprintf("attachment%s", ext)
 	}
 	if m.Message == "" {
-		m.Message = fmt.Sprintf("You received a file: %s", m.Attachment.Name)
+		m.Message = fmt.Sprintf(defaultAttachmentMessage, m.Attachment.Name)
 	}
 	// TODO do not allowed delayed delivery for attachments
 	visitorAttachmentsSize, err := s.cache.AttachmentsSize(v.ip)

server/util.go

@@ -12,8 +12,8 @@ import (
 )
 
 const (
-	peakAttachmentTimeout    = 2500 * time.Millisecond
-	peakAttachmeantReadBytes = 128
+	peakAttachmentTimeout   = 2500 * time.Millisecond
+	peakAttachmentReadBytes = 128
 )
 
 func maybePeakAttachmentURL(m *message) error {
@@ -47,20 +47,21 @@ func maybePeakAttachmentURLInternal(m *message, timeout time.Duration) error {
 	if size, err := strconv.ParseInt(resp.Header.Get("Content-Length"), 10, 64); err == nil {
 		m.Attachment.Size = size
 	}
+	buf := make([]byte, peakAttachmentReadBytes)
+	io.ReadFull(resp.Body, buf) // Best effort: We don't care about the error
+	mimeType, ext := util.DetectContentType(buf, m.Attachment.URL)
 	m.Attachment.Type = resp.Header.Get("Content-Type")
-	if m.Attachment.Type == "" || m.Attachment.Type == "application/octet-stream" {
-		buf := make([]byte, peakAttachmeantReadBytes)
-		io.ReadFull(resp.Body, buf) // Best effort: We don't care about the error
-		m.Attachment.Type = http.DetectContentType(buf)
+	if m.Attachment.Type == "" {
+		m.Attachment.Type = mimeType
 	}
 	if m.Attachment.Name == "" {
 		u, err := url.Parse(m.Attachment.URL)
 		if err != nil {
-			m.Attachment.Name = fmt.Sprintf("attachment%s", util.ExtensionByType(m.Attachment.Type))
+			m.Attachment.Name = fmt.Sprintf("attachment%s", ext)
 		} else {
 			m.Attachment.Name = path.Base(u.Path)
 			if m.Attachment.Name == "." || m.Attachment.Name == "/" {
-				m.Attachment.Name = fmt.Sprintf("attachment%s", util.ExtensionByType(m.Attachment.Type))
+				m.Attachment.Name = fmt.Sprintf("attachment%s", ext)
 			}
 		}
 	}