Golang net/http使用简析

net/http使用简析

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• 路由：路由注册在http.HandlerFunc(Path,handlerfunc)//接收一个资源定位的路径和一个响应函数
• 响应函数HandlerFunc(http.ResponseWriter,*http.Request)//其中http.Writer是一个接口实现了客户端消息的封装，Request获取客户端请求内容
• 在接收参数时需要手动request.ParseForm()解析参数
• http.ListenAndServe(Addr,handler)//启动服务，handler一般为空

结构解析

• http.Request是客户端发出的或者服务端收到的相关信息，Request.Body和Request.Header对应请求头和消息内容，获取json数据时应当使用Body

• http.Response{
  Status string // e.g. “200 OK”
  StatusCode int // e.g. 200
  Proto string // e.g. “HTTP/1.0”
  ProtoMajor int // e.g. 1
  ProtoMinor int // e.g. 0
  …
  }Response对应http回复相关信息

• Request.Form//请求头中的参数

• Request.ParseForm()//解析URL中的查询字符串，并将解析结果更新到Form字段。

• http.Client//http客户端

type Client struct {
    Transport RoundTripper
    CheckRedirect func(req *Request, via []*Request) error
    Jar CookieJar
    Timeout time.Duration
}
常用方法：对应http中客户端发起的请求
func (c *Client) Head(url string) (resp *Response, err error)
func (c *Client) Get(url string) (resp *Response, err error)
func (c *Client) Post(url string, bodyType string, body io.Reader) (resp *Response, err error)
func (c *Client) PostForm(url string, data url.Values) (resp *Response, err error)

• http.Server

	type Server struct {
		Addr           string       
		Handler        Handler     
		ReadTimeout    time.Duration 
		WriteTimeout   time.Duration
		MaxHeaderBytes int         
		TLSConfig      *tls.Config   
		TLSNextProto map[string]func(*Server, *tls.Conn, Handler)
		ConnState func(net.Conn, ConnState)
		ErrorLog *log.Logger
	}Server中的字段是http服务端的配置信息
	func (srv *Server) Serve(l net.Listener) error//监听连接，为每一个加入的连接创建一个协程
	func (srv *Server) ListenAndServe() error//监听srv.Addr指定的TCP地址，并且会调用Serve方法接收到的连接。如果srv.Addr为空字符串，会使用":http"。

• http.Header

type Header map[string][]string//http头域键值对
func (h Header) Get(key string) string//返回键对应值
func (h Header) Set(key, value string)//为Header添加键值对，如果存在则以当前值替换原来的值
func (h Header) Add(key, value string)//为Header添加键值对，如果存在则将当前值添加到值序列中
func (h Header) Del(key string)//删除

• Cookie

type Cookie struct {
	Name  string
	Value string

	Path       string    // optional
	Domain     string    // optional
	Expires    time.Time // optional
	RawExpires string    // for reading cookies only

	// MaxAge=0 means no 'Max-Age' attribute specified.
	// MaxAge<0 means delete cookie now, equivalently 'Max-Age: 0'
	// MaxAge>0 means Max-Age attribute present and given in seconds
	MaxAge   int
	Secure   bool
	HttpOnly bool
	SameSite SameSite
	Raw      string
	Unparsed []string // Raw text of unparsed attribute-value pairs
}相关函数：
http.SetCookie(w ResponseWriter, cookie *Cookie)//添加一个Set-Cookie头部
func SetCookie(w ResponseWriter, cookie *Cookie) {
	if v := cookie.String(); v != "" {
		w.Header().Add("Set-Cookie", v)
	}
}
Request.Cookie(name string)(*Cookie, error)//获取指定Cookie
Request.Cookies()[]*Cookie获取所有Cookie
Request.AddCookie(c *Cookie)
func (r *Request) AddCookie(c *Cookie) {
	s := fmt.Sprintf("%s=%s", sanitizeCookieName(c.Name), sanitizeCookieValue(c.Value))
	if c := r.Header.Get("Cookie"); c != "" {
		r.Header.Set("Cookie", c+"; "+s)
	} else {
		r.Header.Set("Cookie", s)
	}
}//为请求添加cookie

使用实例：

/*
这是一个登陆功能的实现，程序主要是将客户端发送的json数据在服务端解析，并到Mongodb中查询并返回结果
*/
package main

import (
	"encoding/json"
	"fmt"
	"io/ioutil"

	"log"
	"net/http"

	"gopkg.in/mgo.v2"
	"gopkg.in/mgo.v2/bson"
)
func check(err error) {
	if err != nil {
		log.Println(err)
	}
}

type Account struct {
	Username string `json:"username" bson:"username"`
	Password string `json:"password" bson:"passord"`
	Email    string `json:"email"	 bson:"email"`
}

func HomePage(W http.ResponseWriter, Request *http.Request) {
	Request.ParseForm()
	log.Printf("Request Type of Client:%v", Request.Method)
	fmt.Fprint(W, "Homepage")//将需要返回的字段写入W
}

func queryMongoAccount(ch chan bool, user Account) {
	cli, err := mgo.Dial(HOST)
	defer cli.Close()
	check(err)
	collection := cli.DB("account").C("account")
	res, err2 := collection.Find(bson.M{"username": user.Username, "password": user.Password}).Count() //查询是否有记录匹配
	log.Println(bson.M{"username": user.Username, "password": user.Password})
	log.Println(user)
	check(err2)
	if res != 0 {
		ch <- true
	} else {
		ch <- false
	}
	log.Println(res)
}

func IsAccount(W http.ResponseWriter, Request *http.Request) {
	Request.ParseForm()
	account := Account{}
	mongoMessage := make(chan bool)
	body, err := ioutil.ReadAll(Request.Body) //读取POST body
	check(err)
	json.Unmarshal(body, &account)
	if Request.Method == "POST" {
		go queryMongoAccount(mongoMessage, account)
		flag := <-mongoMessage //true or not
		switch flag {
		case true:
			fmt.Fprint(W, "true") //返回页面
		case false:
			fmt.Fprint(W, "false")
		}
	}
}

func StartServer() {
	http.HandleFunc("/", HomePage)//路由设置
	http.HandleFunc("/IsAccount", IsAccount)
	err := http.ListenAndServe(":9090", nil)
	check(err)
}

func main() {
	StartServer()
}