Improve Keep-Alive

[ronag]

llhttp will in certain edge cases (e.g. HEAD, 204, 304) not allow keep-alive to avoid undetectable parsing failures which can lead to data corruption. These can occur when the target server does not properly implement the HTTP/1.1 specification and this is not entirely uncommon.

However, when the target server is known to be spec compliant, this can lead to performance degradation. A typical case for this is when building a microservice architecture where the different services communicate over HTTP/1.1, and the target server is known.

We recently fixed the case for HEAD requests, but more work can be done here.

[metcoder95]

At an llhttp level or within undici? And what else do you have in mind exactly?
wanting to understand the full context 🙂

[ronag]

We can fix it at either level. I think undici is probably easiest for now.