How to easily check if a request's body is empty

[LukasKalbertodt]

Hi there!

I'm not interested in the body's contents, I just want to know whether it is empty.

• I can of course check the Content-Length header, but that is not required to be set correctly.
• Then there is the HttpBody::size_hint, but that's also just a hint that I cannot rely upon.
• Of course I could just download the whole body with body::to_bytes or body::aggregate, but that is wasted time and is also not great for non-trusted inputs because it has no length checks.
• Then there are a couple other methods on HttpBody, but it's not clear to me how exactly they work and what guarantees they give (e.g. if data() returns None, does that mean the body is empty?)

So yes: how to easily check whether a request's body is empty? Thanks!

[sfackler]

The body is empty if data returns none.

[LukasKalbertodt]

Thanks! Would it make sense to put this in the documentation? I think the current wording is a bit ambiguous about that.

[seanmonstar]

Also, the size hint can be depended on, if set. It defaults to the widest range, but if an implementation sets an exact size, like 0, it will be exactly that.