Go语言网络编程http请求

golang-gopher.png

1. 概述

我们简单的描述一下什么是web服务的工作方式,通常一个客户端(客户端可以是浏览器或者其他任何能发送http请求得工具)请求一个URL(uniform resource locator ) ,如果这个url是域名那么首先会去请求DNS(Domain Name System) 获取域名对应的真实IP(InternetProtocol) ,通过IP找到对应的服务器,并与服务器建立TCP(Transmission Control Protocol) 连接,客户端向服务器发送 HTTP Request 数据包,服务服务器处理该请求后,向客户端响应HTTP response 包, 客户端接受这个响应,并做响应的处理,等全部接受之后,就断开这个TCP连接

HTPP协议就是超文本传输协议(HyperText Transfer Protocol ) HTTP协议承载于TCP协议之上的,也可以说HTTP协议的基础是TCP协议

HTTPS协议超文本传输安全协议(Hypertext Transfer Protocol Secure) 就是HTTP协议的安全版,在HTTP的协议基础上加入了TLS(Transport Layer Security 安全传输层协议)或者SSL(Secure Sockets Layer 安全套接层)协议层

通过Go语言来编写一个http服务器非常简单,同时通过Go语言发送http请求也很简单,我们使用 net/http 包就能实现

2. http服务端

package main

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


func defaultFunc(w http.ResponseWriter, r *http.Request) {
    fmt.Println("client connect success ", r.RemoteAddr)
    // 以json格式响应给客户端
    fmt.Fprintf(w, "%v\n", "welcome to user")

}
func main() {
    http.HandleFunc("/", defaultFunc)
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal("ListenAndServer: ", err)
    }
}

3. https服务端

首先在本地构建https证书(windows10环境)

执行指令1

$ openssl genrsa -out server.key 2048
Generating RSA private key, 2048 bit long modulus (2 primes)
..................+++++
........+++++
e is 65537 (0x010001)

执行指令2

$ openssl req -new -x509 -key server.key -out server.crt -days 365
You are about to be asked to enter information that will be incorporated
into your certificate request.
What you are about to enter is what is called a Distinguished Name or a DN.
There are quite a few fields but you can leave some blank
For some fields there will be a default value,
If you enter '.', the field will be left blank.
-----
Country Name (2 letter code) [AU]:CN
State or Province Name (full name) [Some-State]:demo1
Locality Name (eg, city) []:Beijing
Organization Name (eg, company) [Internet Widgits Pty Ltd]:PANG
Organizational Unit Name (eg, section) []:
Common Name (e.g. server FQDN or YOUR name) []:localhost
Email Address []:

package main

import (
    "fmt"
    "net/http"
)

func MyFunc(w http.ResponseWriter, r *http.Request) {
    fmt.Println(r.Method, r.RemoteAddr)
    fmt.Fprintf(w, "%s", "https request")
}
func main() {
    http.HandleFunc("/", MyFunc)
    cf := "E:/Go/src/GoNote/chapter9/demo12/main/server.crt"
    ck := "E:/Go/src/GoNote/chapter9/demo12/main/server.key"
    // 监听8081端口
    http.ListenAndServeTLS(":8081", cf, ck, nil)
}

3. http客户端发送请求

发送http请求,请求方式有POST ,GET ,PUT, DELETE等

编写一个http web服务端用来处理客户端的请求

httpServer.go

package main

import (
    "encoding/json"
    "fmt"
    "log"
    "net/http"
    "time"
)

type responseToClient struct {
    Code    int               `json:"code"`
    Message string            `json:"message"`
    Data    map[string]string `json:"data"`
}

func defaultFunc(w http.ResponseWriter, r *http.Request) {
    var dataForm map[string][]string
    // 标识一个客户端的连接
    fmt.Println("client connect success ", r.RemoteAddr)
    // 获取地址栏内容
    fmt.Println(r.Method, r.RequestURI)
    // 获取请求头内容
    for k, v := range r.Header {
        fmt.Println(k, v[0])
    }
    data := make(map[string]string)
    if err := r.ParseForm(); err == nil {
        if r.Form != nil {
            dataForm = r.Form
        }
    }
    // 读取客户端的内容
    buf := make([]byte, 2048)
    n, _ := r.Body.Read(buf)
    // 获取请求体中的内容
    fmt.Println("receive data from body", string(buf[:n]))

    if r.Method == "GET" {
        // 解析参数
        r.ParseForm()
        for k, v := range r.Form {
            data[k] = v[0]
        }
    }
    // 处理客户端发送的POST请求和PUT请求
    if r.Method == "POST" || r.Method == "PUT" {
        ct, ok := r.Header["Content-Type"]
        if ok {
            // 如果是json数据根据请求头判断
            if ct[0] == "application/json" {
                json.Unmarshal(buf[:n], &data)
            }
            // 如果是POST表单数据
            if ct[0] == "application/x-www-form-urlencoded" {
                if dataForm != nil {
                    for k, v := range dataForm {
                        data[k] = v[0]
                    }
                }
            }
        }
    }
    // 处理客户端的DELETE请求
    // 记录当前时间 `2006-01-02 15:04:05` 是指的格式格式
    data["time"] = time.Now().Format("2006-01-02 15:04:05")
    m := responseToClient{200, "success", data}
    mjson, e := json.Marshal(m)
    if e != nil {
        fmt.Println(e)
    }
    // 以json格式响应给客户端
    fmt.Fprintf(w, "%v\n", string(mjson))

}
func main() {
    http.HandleFunc("/", defaultFunc)
    if err := http.ListenAndServe(":8080", nil); err != nil {
        log.Fatal("ListenAndServer: ", err)
    }
}

编写一能发送http请求的客户端包含 post,get,put,delete请求

httpClients.go

package main

import (
    "bytes"
    "encoding/json"
    "fmt"
    "io/ioutil"
    "log"
    "net/http"
    "net/url"
    "strconv"
    "strings"
)

const BC = "http://127.0.0.1:8080/"

// 发送一个简单的http GET请求
func httpSimpleGet() {
    resp, err := http.Get(BC + "index?aa=AA&bb=BB")
    if err != nil {
        log.Println(err)
    }
    defer resp.Body.Close()
    // 获取响应内容
    resultByte, _ := ioutil.ReadAll(resp.Body)
    fmt.Println(string(resultByte))
}

// 设置请求头和请求参数的Get请求
func httpGet() {
    client := &http.Client{}
    request, err := http.NewRequest("GET", BC, nil)
    if err != nil {
        log.Println(err)
    }
    // 在请求头中添加自定义数据
    request.Header.Add("company", "PG")
    request.Header.Add("appkey", "Test_0001")
    // 添加请求参数
    params := request.URL.Query()
    params.Add("name", "pg")
    params.Add("addr", "chain")
    request.URL.RawQuery = params.Encode()
    // 发送http请求,请求成功,获取响应
    resp, err := client.Do(request)
    if err != nil {
        log.Println(err)
    }
    // 获取所有的响应内容
    result, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        log.Println(err)
    }
    // 打印响应的内容
    fmt.Println(string(result))
}

// http POST请求,并发送json数据
func httpPostJson() {
    // post json 数据应用比较广泛
    // 发送json数据,我们一般是用使用map或者结构体存储数据
    // 然后转换成json数据
    // 然后转换成byte数据,放在发送的body中一起发送
    // 我们模拟一下这个过程
    var std map[string]string = map[string]string{"work": "programmer", "skills": "golang", "addr": "北京"}
    data, err := json.Marshal(std)
    if err != nil {
        log.Println(err)
    }
    body := bytes.NewBuffer([]byte(data))
    req, err := http.NewRequest("POST", BC, body)
    if err != nil {
        log.Println(err)
    }
    // 设置请求头
    req.Header.Add("Accept", "application/json")
    req.Header.Add("Content-Type", "application/json")
    resp, err := http.DefaultClient.Do(req)
    defer resp.Body.Close()
    if err != nil {
        log.Println(err)
    }
    result, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        log.Println(err)
    }
    fmt.Println(string(result))
}

// 模拟post发送表单数据
func HttpPosForm() {
    formData := url.Values{}
    formData.Set("userName", "admin")
    formData.Set("userPwd", "admin123456")
    req, err := http.NewRequest("POST", BC, strings.NewReader(formData.Encode()))
    if err != nil {
        log.Println(err)
    }
    req.Header.Set("Content-Type", "application/x-www-form-urlencoded")
    req.Header.Set("Content-Length", strconv.Itoa(len(formData.Encode())))
    resp, err := http.DefaultClient.Do(req)
    if err != nil {
        log.Println(err)
    }
    defer resp.Body.Close()
    result, err := ioutil.ReadAll(resp.Body)
    fmt.Println(string(result))

}

// 模拟客户端发送PUT请求
func HttpPut() {
    // 发送PUT请求和POST请求类似都可以发送json和form数据
    std := map[string]string{"method": "PUT"}
    data, err := json.Marshal(std)
    if err != nil {
        log.Println(err)
    }
    body := bytes.NewBuffer([]byte(data))
    req, err := http.NewRequest("PUT", BC, body)
    if err != nil {
        log.Println(err)
    }
    req.Header.Add("Content-Type", "application/json")
    resp, err := http.DefaultClient.Do(req)
    defer resp.Body.Close()
    if err != nil {
        log.Println(err)
    }
    result, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        log.Println(err)
    }
    fmt.Println(string(result))
}

//模拟客户端发送DELETE请求
func HttpDelete() {
    req, err := http.NewRequest("DELETE", BC, nil)
    if err != nil {
        log.Println(err)
    }
    // 添加请求参数 与发送get请求类似
    params := req.URL.Query()
    params.Add("user", "pahnaskdjalsdklasd")
    req.URL.RawQuery = params.Encode()
    // 发送http请求,请求成功,获取响应
    resp, err := http.DefaultClient.Do(req)
    if err != nil {
        log.Println(err)
    }
    // 获取所有的响应内容
    result, err := ioutil.ReadAll(resp.Body)
    if err != nil {
        log.Println(err)
    }
    // 打印响应的内容
    fmt.Println(string(result))
}
func main() {

    //httpSimpleGet()
    //httpGet()
    //httpPostJson()
    //HttpPosForm()
    //HttpPut()
    HttpDelete()
}