"net/http"包定义了9个请求类型常量
const (
	MethodGet     = "GET"
	MethodHead    = "HEAD"
	MethodPost    = "POST"
	MethodPut     = "PUT"
	MethodPatch   = "PATCH" // RFC 5789
	MethodDelete  = "DELETE"
	MethodConnect = "CONNECT"
	MethodOptions = "OPTIONS"
	MethodTrace   = "TRACE"
)

func NewRequestWithContext(ctx context.Context, method, url string, body io.Reader) (*Request, error)
func NewRequest(method, url string, body io.Reader) (*Request, error) {
	return NewRequestWithContext(context.Background(), method, url, body)
}

func (c *Client) Do(req *Request) (*Response, error)
func (c *Client) Get(url string) (resp *Response, err error)
func (c *Client) Head(url string) (resp *Response, err error)
func (c *Client) Post(url, contentType string, body io.Reader) (resp *Response, err error)
func (c *Client) PostForm(url string, data url.Values) (resp *Response, err error) {
	c.Post(url, "application/x-www-form-urlencoded", strings.NewReader(data.Encode()))
}

使用DefaultClient请求的简写
func Get(url string) (resp *Response, err error)
func Head(url string) (resp *Response, err error)
func Post(url, contentType string, body io.Reader) (resp *Response, err error)
func PostForm(url string, data url.Values) (resp *Response, err error)

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package request

import (
	"crypto/tls"
	"fmt"
	"io"
	"net/http"
	"time"
)
//要管理HTTP客户端的头域、重定向策略和其他设置，创建一个Client
//要管理代理、TLS配置、keep-alive、压缩和其他设置，创建一个Transport
//Client和Transport类型都可以安全的被多个go程同时使用。出于效率考虑，应该一次建立、尽量重用。
var client = &http.Client{
	Timeout:   6*time.Second,
	Transport: &http.Transport{TLSClientConfig: &tls.Config{InsecureSkipVerify: true}}, //如为nil则使用DefaultTransport
}

func Example() {
	req, err := http.NewRequest(http.MethodPost, "http://php.local/reply.php", http.NoBody)
	if err != nil {
		fmt.Print(err)
		return
	}
	req.Header.Set("Content-Type", "application/json")
	req.Header.Add("X-Request-Id", "request-id")
	resp, err := client.Do(req)
	if err != nil {
		fmt.Print(err)
		return
	}
	defer resp.Body.Close() //程序在使用完回复后必须关闭回复的主体。

	body, _ := io.ReadAll(resp.Body)
	fmt.Print(string(body))
}

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服务端接口
type Handler interface {
	ServeHTTP(ResponseWriter, *Request)
}
type HandlerFunc func(ResponseWriter, *Request)
func (f HandlerFunc) ServeHTTP(w ResponseWriter, r *Request) {
	f(w, r)
}

ServeMux是一个HTTP请求多路复用器。它根据已注册模式列表匹配每个传入请求的URL，并调用与URL最匹配的模式的处理程序。

func NewServeMux() *ServeMux { return new(ServeMux) }
func (mux *ServeMux) Handle(pattern string, handler Handler)
func (mux *ServeMux) HandleFunc(pattern string, handler func(ResponseWriter, *Request)) {
	mux.Handle(pattern, HandlerFunc(handler))
}

使用DefaultServeMux提供服务的简写
func Handle(pattern string, handler Handler)
func HandleFunc(pattern string, handler func(ResponseWriter, *Request))

Server定义运行HTTP服务器的参数，零值是一个有效的配置。

func (srv *Server) ListenAndServe() error

func (srv *Server) Shutdown(ctx context.Context) error
不中断任何活动连接的情况下优雅地关闭服务器。

func ListenAndServe(addr string, handler Handler) error {
	server := &Server{Addr: addr, Handler: handler}
	return server.ListenAndServe()
}
handler为nil时使用DefaultServeMux

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判断字节流的文件类型可使用：
http.DetectContentType(b []byte) string
能识别的常用文件类型有：
application/pdf
application/zip
image/gif
image/png
image/jpeg
image/bmp
image/webp
audio/aiff
audio/mpeg
audio/midi
audio/wave
application/ogg
video/avi
video/webm
video/mp4
font/ttf
font/otf
网页文档类型返回 text/html; charset=utf-8
多数文本类型多返回 text/plain; charset=utf-8
不能识别的类型将返回 application/octet-stream