>文章来自于：https://reading.developerlearning.cn/reading/7-2018-05-24-net-http-part1/
## 视频回看
https://youtu.be/H3oXjpiOReQ
*Go 标准包阅读*
Go 版本：go 1.10.1
### net/http
- server.go
### 问题
1. Next Protocol Negotiation = NPN
2. Expect 100 Continue support
>见参考资料
3. header提到了：Expect和host
4. 判断了 header里面的HOST，但是后面又删除，为什么？
server.go#L980
```go
delete(req.Header, "Host")
```
5. 判断是否支持 HTTP2 （isH2Upgrade）
```go
// isH2Upgrade reports whether r represents the http2 "client preface"
// magic string.
func (r *Request) isH2Upgrade() bool {
return r.Method == "PRI" && len(r.Header) == 0 && r.URL.Path == "*" && r.Proto == "HTTP/2.0"
}
```
```go
调用：ProtoAtLeast(1, 1)
...
// ProtoAtLeast reports whether the HTTP protocol used
// in the request is at least major.minor.
func (r *Request) ProtoAtLeast(major, minor int) bool {
return r.ProtoMajor > major ||
r.ProtoMajor == major && r.ProtoMinor >= minor
}
```
## 延伸阅读
1. https://github.com/golang/go/issues/22128
2. https://tools.ietf.org/html/draft-ietf-httpbis-p2-semantics-26#section-6.2.1
3. https://www.cnblogs.com/tekkaman/archive/2013/04/03/2997781.html
4. https://benramsey.com/blog/2008/04/http-status-100-continue/
5. http://www.ituring.com.cn/article/130844
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