资源mp4播放问题

app/views/attachment_histories/_attachment_history.json.jbuilder

@@ -10,3 +10,4 @@ json.created_on attachment.created_on
 json.is_pdf attachment.is_history_pdf?
 json.url attachment.is_history_pdf? ? attachment_path(attachment, type: 'history',disposition:"inline") : attachment_path(attachment, type: 'history')
 json.attachment_id attachment.attachment_id
+json.content_type attachment.content_type

app/views/attachments/_attachment_small.json.jbuilder

@@ -4,3 +4,4 @@ json.filesize number_to_human_size(attachment.filesize)
 json.is_pdf attachment.is_pdf?
 json.url attachment.is_pdf? ? download_url(attachment,disposition:"inline") : download_url(attachment)
 json.created_on attachment.created_on
+json.content_type attachment.content_type