3 ms·

But it doesn’t allow you to multiplex that connection (HTTP pipelining is broken and usually disabled). So depending on the app setup you could be losing quite

But it doesn’t allow you to multiplex that connection (HTTP pipelining is broken and usually disabled). So depending on the app setup you could be losing quite a bit waiting on an API call while you could be loading a CSS file.

wizzwizz4 2y ago
Your static and dynamic assets should be served from different domains anyway, to reduce the overhead of authentication headers / improve cache coherency. https://sstatic.net/ https://sstatic.net/ quotes a good explanation, apparently mirrored https://checkmyws.github.io/yslow-rules/ https://checkmyws.github.io/yslow-rules/. (The original Yahoo Best Practices for Speeding Up Your Web Site article has been taken down.)
- mananaysiempre 2y ago
  Why does saving on cookies outweigh having to go through an additional TCP slow start?
  - wizzwizz4 2y ago
    Consider HTTP semantics. If there are cookies in the request, and those cookies change, it has to be re-requested every time. If there are no cookies, the request can remain semantically compatible, so the browser's internal caching proxy can just return the cached version. There are other advantages: the article elaborates.
    - mananaysiempre 2y ago
      Per the official HTTP semantics[1,2], what you say is not true: the only header that’s (effectively) always part of Vary is Authorization, the rest are at the origin server’s discretion; so don’t set Vary: Cookie on responses corresponding to static assets and you’re golden. The article only says that some (all?) browsers will disregard this and count Cookie there as well. Even still, the question is, what’s worse: a cacheable request that has to go through DNS and a slow-start stage because it’s to an unrelated domain, or a potentially(?) noncacheable one that can reuse the existing connection? On a fast Internet connection, the answer is nonobvious to me. [1] https://www.rfc-editor.org/rfc/rfc9110.html#name-vary https://www.rfc-editor.org/rfc/rfc9110.html#name-vary [2] https://datatracker.ietf.org/doc/html/rfc6265#section-3 https://datatracker.ietf.org/doc/html/rfc6265#section-3
      - wizzwizz4 2y ago
        Oh, would that anyone heeded the official HTTP semantics. (Web browsers barely let you make requests other than GET and POST! It's ridiculous.) On a fast internet connection, the answer doesn't matter because the internet connection is fast. On a slow internet connection, cacheable requests are better.

wizzwizz4 2y ago

Your static and dynamic assets should be served from different domains anyway, to reduce the overhead of authentication headers / improve cache coherency. https://sstatic.net/ https://sstatic.net/ quotes a good explanation, apparently mirrored https://checkmyws.github.io/yslow-rules/ https://checkmyws.github.io/yslow-rules/. (The original Yahoo Best Practices for Speeding Up Your Web Site article has been taken down.)

mananaysiempre 2y ago
Why does saving on cookies outweigh having to go through an additional TCP slow start?
- wizzwizz4 2y ago
  Consider HTTP semantics. If there are cookies in the request, and those cookies change, it has to be re-requested every time. If there are no cookies, the request can remain semantically compatible, so the browser's internal caching proxy can just return the cached version. There are other advantages: the article elaborates.
  - mananaysiempre 2y ago
    Per the official HTTP semantics[1,2], what you say is not true: the only header that’s (effectively) always part of Vary is Authorization, the rest are at the origin server’s discretion; so don’t set Vary: Cookie on responses corresponding to static assets and you’re golden. The article only says that some (all?) browsers will disregard this and count Cookie there as well. Even still, the question is, what’s worse: a cacheable request that has to go through DNS and a slow-start stage because it’s to an unrelated domain, or a potentially(?) noncacheable one that can reuse the existing connection? On a fast Internet connection, the answer is nonobvious to me. [1] https://www.rfc-editor.org/rfc/rfc9110.html#name-vary https://www.rfc-editor.org/rfc/rfc9110.html#name-vary [2] https://datatracker.ietf.org/doc/html/rfc6265#section-3 https://datatracker.ietf.org/doc/html/rfc6265#section-3
    - wizzwizz4 2y ago
      Oh, would that anyone heeded the official HTTP semantics. (Web browsers barely let you make requests other than GET and POST! It's ridiculous.) On a fast internet connection, the answer doesn't matter because the internet connection is fast. On a slow internet connection, cacheable requests are better.