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nitely

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HTTP/2 zero latency write coalescing

nitely.github.io
8 points·by nitely·anno scorso·0 comments

HTTP/2 in-depth server design

nitely.github.io
1 points·by nitely·anno scorso·0 comments

HTTP/2 in-depth server design

nitely.github.io
4 points·by nitely·2 anni fa·0 comments

comments

nitely
·4 mesi fa·discuss
It's similar to RE2, but it lacks the on the fly DFA, ie: it's just the classic Thompson's NFA with some tweaks. It does not implement find all the same way, though.
nitely
·4 mesi fa·discuss
FWIW, nim-regex does achieve linear time in the rebar test[0], even if the regex includes capture groups. It's NFA based.

[0]: https://github.com/BurntSushi/rebar/pull/20#issuecomment-256...
nitely
·anno scorso·discuss
Yes, and the client may do multiple requests, and if all take long to be processed you may end up with a lot of open connections at the same time (at least on http1), so there is a point to fast HTTP requests+SSE, instead of slow requests (and no SSE). Granted, if the server is HTTP2 the requests can share the same connection, but then it'd be similar to just using WS for this usage. Also, this allows to queue the work, and processed it either sequentially or concurrently.

By async I meant a process that may take longer than you are willing to do within the request/response cycle, not necessarily async IO.
nitely
·anno scorso·discuss
> What benefit is SSE providing here? Let the client decide when a session starts/ends by generating IDs and let the server maintain that session internally.

The response is generated asynchronously, instead of within the HTTP request/response cycle, and sent over SSE later. But emulating WS with HTTP requests+SSE seems very iffy, indeed.
nitely
·anno scorso·discuss
not if you need bidirectional communication, for example a ping-pong of request/response. That is solved with WS, but hard to do with SSE+requests. The client requests may not even hit the same SSE server depending on your setup. There are workarounds obviously, but it complicates things.
nitely
·anno scorso·discuss
There is a gem that implements lightweight threads[0], and there is an HTTP/2 server that seems to abstract things out[1]. Your point probably still holds in the context of ruby + async + http/2; but then it's not http/2 fault, but rather ruby for not having a better concurrency story, like say golang.

[0]: https://github.com/socketry/async

[1]: https://github.com/socketry/falcon
nitely
·anno scorso·discuss
In reality you would build your application server on top of the HTTP/2 server, so you'd not have to deal with multiplexing, the server will hide that from you, so it's the same as an HTTP/1 server (ex: you pass some callback that gets called to handle the request). If you implement HTTP/2 from scratch, multiplexing is not even the most complex part... It's rather the sum of all parts: HPACK, flow-control, stream state, frames, settings, the large amount of validations, and so on.
nitely
·anno scorso·discuss
> I think ReadableStream/WritableStream APIs on browsers were supposed to change that, but I haven't followed the progress in the last few years.

There has been a lot of pushback against supporting full-duplex streams[0].

[0]: https://github.com/whatwg/fetch/issues/1254
nitely
·anno scorso·discuss
> A h2 proxy usually wouldn't proxy through the http2 connection, it would instead accept h2, load-balance each request to a backend over a h2 (or h1) connection.

Each connection need to keep state of all processed requests (the HPACK dynamic headers table), so all request for a given connection need to be proxied through the same connection. Not sure I got what you meant, though.

Apart from that, I think the second sentence of my comment makes clear there is no smuggling as long as the connection before/past proxy is http2, and it's not downgraded to http1. That's all that I meant.
nitely
·anno scorso·discuss
In theory request smuggling is not possible with end-to-end HTTP/2. It's only possible if there is a downgrade to HTTP/1 at some point.
nitely
·2 anni fa·discuss
They are going to add boilerplate free error handling sooner or later. There are many proposals for "Go 2" already.
nitely
·2 anni fa·discuss
Something not mentioned: web-browsers limit the number of connections per domain to 6. With +http/2 they will use a single connection for multiple concurrent requests.
nitely
·2 anni fa·discuss
If those libraries are doing something at import time, then it could take any amount of time, TBF.
nitely
·2 anni fa·discuss
I'll second this. There are a lot of good managers that care more about the product than some team metrics. Same for coworkers that care about improving. Don't let one bad manager define how you'll do things in your next job.
nitely
·2 anni fa·discuss
Look-arounds can be implemented in quadratic time for unbounded expressions (i.e: containing +, *), and linear time for bounded expressions quite easily. And I suspect they can be implemented in (super)linear time in general by matching them in parallel to the NFA.
nitely
·8 anni fa·discuss
Why would it be ok to suggest changes after a year then (which is fairly arbitrary btw), according to that logic?

TBH, I'd only suggest changes when they are really required (i.e scalability issues, maintenance issues, etc) but that has nothing to do with how long I've been working in a project. Requiring a year of knowledge about the domain is nonsense to me.