Hacker News Reader

As I've heard it explained, the server will push what it thinks is relevant [1] and if the resource is already cached in the client, the client will ask the server to stop the push.

The relevant mechanism seems to be described here: https://http2.github.io/http2-spec/#PushResponses

[1]: By some criteria. I don't have details here.

View on HN

That's my understanding as well, but it's pretty fuzzy. How does the client stop the push, and what are the performance implications of this? Pages currently include dozens of external resources, and this will get worse if developers stop using bundles and sprites (because in theory HTTP/2 makes them pointless).

They send RST_STREAM, which can be done as soon as PUSH_PROMISE is received (which SHOULD [RFC2119] be sent before any data).

As I understand it, the more latent the connection the worse the behaviour (i.e., the more likely you are to receive too much data you don't need).

Reply on news.ycombinator.com