查看“︁HTTP/2”︁的源代码


== HTTP/2 Discovery ==
;h2: HTTP/2 over TLS
;h2c: HTTP/2 is run over cleartext TCP

== Starting HTTP/2 for "http" URIs==
如果客户端无法事先知道服务端是否支持http2，可以通过HTTP Upgrade mechanism（定义在HTTP/1.1）中来实现，这样在之后的请求中可以采取HTTP/2。

<syntaxhighlight lang="lisp">
GET / HTTP/1.1
Host: server.example.com
Connection: Upgrade, HTTP2-Settings
Upgrade: h2c
HTTP2-Settings: <base64url encoding of HTTP/2 SETTINGS payload>
</syntaxhighlight>

这样的话，如果请求中由payload必须一次性发完。然后才能升级到HTTP/2。另一种办法是通过<span class="article-label">OPTIONS</span>请求
来判断，这样做会多一次请求。

如果服务端不支持HTTP/2，返回中则不包含Upgrade header:

<syntaxhighlight lang="lisp">
HTTP/1.1 200 OK
Content-Length: 243
Content-Type: text/html
</syntaxhighlight>

否则，返回一个101 (Switching Protocols)响应：

<syntaxhighlight lang="lisp">
HTTP/1.1 101 Switching Protocols
Connection: Upgrade
Upgrade: h2c

[ HTTP/2 connection ...
</syntaxhighlight>

在h2c后面的空行之后，就可以开始发送HTTP/2的frame了。

=== HTTP2-Settings ===

[[Category:Network]]