Language code sample crawler agent golang

package main

    import (
        "net/url"
        "net/http"
        "bytes"
        "fmt"
        "io/ioutil"
        "math/rand"
        "time"
        "strconv"
    )

    const ProxyServer = "t.16yun.cn:31111"

    type ProxyAuth struct {
        Username string
        Password string
    }

    func (p ProxyAuth) ProxyClient() http.Client {
       if p.Username != nil and p.Password != nil{
           proxyURL, _ := url.Parse("http://" + p.Username + ":" + p.Password + "@" + ProxyServer)
       }else{
           proxyURL, _ := url.Parse("http://" + ProxyServer)
       }
       return http.Client{Transport: &http.Transport{Proxy:http.ProxyURL(proxyURL)}}
    }

    func main()  {
        targetURI := "http://httpbin.org/ip"

        // 初始化 proxy http client
        client := ProxyAuth{License: "username", SecretKey: "password"}.ProxyClient()

        request, _ := http.NewRequest("GET", targetURI, bytes.NewBuffer([] byte(``)))

        // 设置Proxy-Tunnel
        // rand.Seed(time.Now().UnixNano())
        // tunnel := rand.Intn(10000)
        // request.Header.Set("Proxy-Tunnel", strconv.Itoa(tunnel) )

        response, err := client.Do(request)

        if err != nil {
            panic("failed to connect: " + err.Error())
        } else {
            bodyByte, err := ioutil.ReadAll(response.Body)
            if err != nil {
                fmt.Println("读取 Body 时出错", err)
                return
            }
            response.Body.Close()

            body := string(bodyByte)

            fmt.Println("Response Status:", response.Status)
            fmt.Println("Response Header:", response.Header)
            fmt.Println("Response Body:\n", body)
        }
    }