golang中net/http包的簡單使用

一、介紹

http包提供了http客戶端和服務端的實現

Get，Head，Post和PostForm函數發出http、https的請求

程序在使用完回復后必須關閉回復的主體

#簡單的訪問網站，由於沒有添加header，訪問數據不正確
package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    res,err:=http.Get("https://www.baidu.com")
    if err !=nil{
        panic(err)
    }
    defer res.Body.Close()
    body, err := ioutil.ReadAll(res.Body)
    fmt.Println(string(body))
}

#建立的client客戶端，發起的get請求，在請求體中添加header，然后使用client執行這個請求
package main

import (
    "fmt"
    "io/ioutil"
    "net/http"
)

func main() {
    client:=&http.Client{}
    res,err:=http.NewRequest("GET","https://www.baidu.com",nil)
    res.Header.Add("User-Agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/75.0.3770.100 Safari/537.36")
    resp,err:=client.Do(res)
    if err != nil {
        panic(err)
    }
    defer resp.Body.Close()
    body, err := ioutil.ReadAll(resp.Body)
    fmt.Println(string(body))
}

二、其他使用方法

#監聽ip端口，並建立一個sever，讓訪問者可以訪問指定的文件目錄
package main

import "net/http"

func main() {
　　//設置訪問路由
    http.Handle("/",http.FileServer(http.Dir("./")))
    http.ListenAndServe(":8080",nil)
}

package main

import (
    "bufio"
    "fmt"
    "github.com/axgle/mahonia"
    "golang.org/x/net/html/charset"
    "golang.org/x/text/encoding"
    "io"
    "io/ioutil"
    "net/http"
    "strconv"
)

func main() {
    client := &http.Client{}
    request, err := http.NewRequest("GET", "http://www.baidu.com", nil)
    if err != nil {
        fmt.Println(err)
    }
    //建立cookie對象
    cookie := &http.Cookie{Name: "maple", Value: strconv.Itoa(123)}
    request.AddCookie(cookie) //向request中添加cookie

    //設置request的header
    request.Header.Set("Accept", "text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3")
    request.Header.Set("Accept-Language", "zh-CN,zh;q=0.9")
    request.Header.Set("Cache-Control", "no-cache")
    request.Header.Set("Connection", "keep-alive")

    response, err := client.Do(request)
    if err != nil {
        fmt.Println(err)
        return
    }
    e:=determineEncoding(response.Body)
    fmt.Println("當前編碼：",e)

    defer response.Body.Close()
    if response.StatusCode == 200 {
        r, err := ioutil.ReadAll(response.Body)
        if err != nil {
            fmt.Println(err)
        }


        //編碼轉換，如編碼不正確可轉成指定編碼
        srcCoder :=mahonia.NewEncoder("utf-8")
        res:=srcCoder.ConvertString(string(r))

        fmt.Println(res)
    }
}

//編碼檢測
func determineEncoding(r io.Reader) encoding.Encoding  {
    bytes, err := bufio.NewReader(r).Peek(1024)
    if err != nil {
        panic(err)
    }
    e, _, _ := charset.DetermineEncoding(bytes, "")
    return e
}