Attachment size limit

server/config.go

@@ -14,7 +14,7 @@ const (
 	DefaultMinDelay                  = 10 * time.Second
 	DefaultMaxDelay                  = 3 * 24 * time.Hour
 	DefaultMessageLimit              = 4096 // Bytes
-	DefaultAttachmentSizeLimit       = 15 * 1024 * 1024
+	DefaultAttachmentSizeLimit       = int64(15 * 1024 * 1024)
 	DefaultAttachmentSizePreviewMax  = 20 * 1024 * 1024 // Bytes
 	DefaultAttachmentExpiryDuration  = 3 * time.Hour
 	DefaultFirebaseKeepaliveInterval = 3 * time.Hour // Not too frequently to save battery

server/message.go

@@ -32,10 +32,10 @@ type message struct {
 
 type attachment struct {
 	Name       string `json:"name"`
-	Type       string `json:"type"`
-	Size       int64  `json:"size"`
-	Expires    int64  `json:"expires"`
-	PreviewURL string `json:"preview_url"`
+	Type       string `json:"type,omitempty"`
+	Size       int64  `json:"size,omitempty"`
+	Expires    int64  `json:"expires,omitempty"`
+	PreviewURL string `json:"preview_url,omitempty"`
 	URL        string `json:"url"`
 }