go语言渐入佳境-网络[16]-http

##获取网站内容

package main

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

func main(){

	resp,err:= http.Get("http://www.zhenai.com/zhenghun")

	if err!=nil{
		panic(err)
	}


	defer resp.Body.Close()

	if resp.StatusCode == http.StatusOK{
		all,err:=ioutil.ReadAll(resp.Body)
		if err!=nil{
			panic(err)
		}
		fmt.Printf("%s\n",all)
	}
}

当charset为gbk时，转换为utf-8

下载辅助包

gopm get -g -v golang.org/x/text
gopm get -g -v golang.org/x/net/html

package main

import (
	"net/http"
	"io/ioutil"
	"fmt"
	"io"
	"golang.org/x/net/html/charset"
	"golang.org/x/text/encoding"
	"bufio"
	"golang.org/x/text/transform"
)

func main(){

	resp,err:= http.Get("http://www.chinanews.com/")

	if err!=nil{
		panic(err)
	}


	defer resp.Body.Close()
	if resp.StatusCode != http.StatusOK{
		fmt.Println("Error: status code",resp.StatusCode)
	}
	e:= determineEncoding(resp.Body)
	utf8reader:= transform.NewReader(resp.Body,e.NewDecoder())

	all,err:= ioutil.ReadAll(utf8reader)
	if err!=nil{
		panic(err)
	}
	fmt.Printf("%s\n",all)



}



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
}

http服务器1

访问localhost：8000，打印出URL.Path = “/”

package main

import (
	"fmt"
	"log"
	"net/http"
)

func main() {
	http.HandleFunc("/", handler) // each request calls handler
	log.Fatal(http.ListenAndServe("localhost:8000", nil))
}

// handler echoes the Path component of the requested URL.
func handler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "URL.Path = %q\n", r.URL.Path)
}

http服务器2

计数：

package main

import (
	"fmt"
	"log"
	"net/http"
	"sync"
)

var mu sync.Mutex
var count int

func main() {
	http.HandleFunc("/", handler)
	http.HandleFunc("/count", counter)
	log.Fatal(http.ListenAndServe("localhost:8000", nil))
}

// handler echoes the Path component of the requested URL.
func handler(w http.ResponseWriter, r *http.Request) {
	mu.Lock()
	count++
	mu.Unlock()
	fmt.Fprintf(w, "URL.Path = %q\n", r.URL.Path)
}

// counter echoes the number of calls so far.
func counter(w http.ResponseWriter, r *http.Request) {
	mu.Lock()
	fmt.Fprintf(w, "Count %d\n", count)
	mu.Unlock()
}

http服务器2

package main

import (
	"fmt"
	"log"
	"net/http"
)

func main() {
	http.HandleFunc("/", handler)
	log.Fatal(http.ListenAndServe("localhost:8000", nil))
}

//!+handler
// handler echoes the HTTP request.
func handler(w http.ResponseWriter, r *http.Request) {
	fmt.Fprintf(w, "%s %s %s\n", r.Method, r.URL, r.Proto)
	for k, v := range r.Header {
		fmt.Fprintf(w, "Header[%q] = %q\n", k, v)
	}
	fmt.Fprintf(w, "Host = %q\n", r.Host)
	fmt.Fprintf(w, "RemoteAddr = %q\n", r.RemoteAddr)
	if err := r.ParseForm(); err != nil {
		log.Print(err)
	}
	for k, v := range r.Form {
		fmt.Fprintf(w, "Form[%q] = %q\n", k, v)
	}
}

输出：

GET / HTTP/1.1
Header["Connection"] = ["keep-alive"]
Header["Upgrade-Insecure-Requests"] = ["1"]
Header["User-Agent"] = ["Mozilla/5.0 (Macintosh; Intel Mac OS X 10_13_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/71.0.3578.98 Safari/537.36"]
Header["Accept-Encoding"] = ["gzip, deflate, br"]
Header["Cookie"] = ["_ga=GA1.1.809627859.1535126425; io=nukCk_cXUcwmTK_-AAAC"]
Header["Cache-Control"] = ["max-age=0"]
Header["Accept"] = ["text/html,application/xhtml+xml,application/xml;q=0.9,image/webp,image/apng,*/*;q=0.8"]
Header["Accept-Language"] = ["zh-CN,zh;q=0.9"]
Host = "localhost:8000"
RemoteAddr = "127.0.0.1:56512"

http文件服务器

/* File Server
 */

package main

import (
	"fmt"
	"net/http"
	"os"
)

func main() {
	// deliver files from the directory /var/www
	//fileServer := http.FileServer(http.Dir("/var/www"))
	fileServer := http.FileServer(http.Dir("/Users/jackson/"))

	// register the handler and deliver requests to it
	err := http.ListenAndServe(":8000", fileServer)
	checkError(err)
	// That's it!
}

func checkError(err error) {
	if err != nil {
		fmt.Println("Fatal error ", err.Error())
		os.Exit(1)
	}
}