消息 headers: Content-Type: charset="UTF-8" 和 Content-Transfer-Encoding 之间的区别: 8bit

Question

我收到了一些邮件消息，但我对这些感到困惑headers:

Content-Type: text/plain;
    format=flowed;
    charset="UTF-8";
    reply-type=response
Content-Transfer-Encoding: 8bit

既然已经指定了Content-Type: charset="UTF-8"，为什么还要Content-Transfer-Encoding: 8bit？

Answer 1

因为你还可以拥有：

Content-Type: text/plain; charset=utf-8
Content-Transfer-Encoding: base64

字符集独立于内容编码。

Difference between message headers: Content-Type: charset="UTF-8" and Content-Transfer-Encoding: 8bit