What should the Content-Type be for a 4xx error without a body?

问题

Consider an HTTP request that gets the following response:

405 Method Not Allowed
Content-Length: 0

What should the content-type of something like this be?

• Set to nothing?
• Not set?
• Set to text/plain or text/html

回答1:

You haven't got any content, therefore I wouldn't set a Content-Type at all. If you find that causes problems to clients (which seems unlikely, to be honest), I'd probably go with text/plain - definitely not text/html, as your "empty content" is not an HTML document.

来源：https://stackoverflow.com/questions/15032932/what-should-the-content-type-be-for-a-4xx-error-without-a-body