http2

something we should know

http is old

HTTP/1.1 has served the Web well for more than fifteen years, But it's not meant to be a perfect solution, its age is starting to show.

diagram of http lifecycle

http is stateless

It means each request must contain enough information on their own to fulfill the request. Even the information is shared during lifecycle.

For example: sessionID is always in the header for each request.

http is limited

Websites nowadays include many different components, such as HTML, CSS, JavaScript, images, video and Flash animations...

But HTTP practically only allows one request per TCP connection. It's still limited even modern browsers have used multiple TCP connections to issue parallel requests.

what we have now?

in-lining
spriting
concatenation
eager loading
GraphQL

All above solutions are for reducing request

Why http2

http2 is binary, instead of textual
http2 is fully multiplexed, instead of ordered and blocking
http2 can therefore use one connection for parallelism
http2 uses header compression to reduce overhead
allows servers to “push” responses proactively into client caches

how we use it

with reverse proxy

You dont't have to do anything to your backend, just leave it as what it was.

with backend

Dart	Haskell	Ruby	Go	C#	Python	Rust	Java	Lua	Erlang	NodeJS	Objective-C/Swift
Dart	second-transfer ShimmerCat Warp	http-2	http2	HttpTwo	hyper	hyper	Shaka Jetty Netty OkHttp Undertow	lua-http	lucid	node-http2 Sasazka	WKWebView