HTTP responses with no mime type (content-type) and/or body (content-length) is not possible

[bbotsch-mpengs]

As far as I can tell, it is not possible to send an HTTP response with no mime type or body. You are forced to pick a mime type even if the body is empty and you are forced to send a content-length even if the length is 0. This is sometimes weird when you are forced to pick a mime type for an empty body when sending a 302 redirect for example. Other times it is wrong according to the spec.

Cases (non-exhaustive) where content-length MUST NOT be sent:

• 204 No Content
• 304 Not Modified (unless it is the same value as it would send in a 200 OK response for the same resource, AKA not the length of this actual response)
• See https://httpwg.org/specs/rfc9110.html#field.content-length

There are places in the codebase where the mime type is set to HTML or TEXT with an empty body for things like "Not Found", "Not Modified", "Method Not Allowed", and "Internal Server Error". While this is mostly harmless, it's just not necessary and so it feels weird.

[mookums]

Hello,

Will take a look at getting this resolved in the coming days. This is a historical artifact from early development cycles and should be fairly easy to patch.