三个案例

猜数字

1. 生成随机数

maxNum := 100  
rand.Seed(time.Now().UnixNano()) //改版本了  
secretNum := rand.Intn(maxNum)  
fmt.Println(secretNum)  

2. 用户输入

var input int  
fmt.Println("please enter the number:")  
fmt.Scanf("%d", &input) //输入%c会显示0  
fmt.Println("your number is:", input)  

3. 循环

for {  
fmt.Println("please enter the number:")  
fmt.Scanf("%d\n", &input) //输入char会显示0, 注意需要加\n，因为会读取换行符  
fmt.Println("your number is:", input)  
// if else  
if input == secretNum {  
fmt.Println("good guess! ")  
break  
} else if input > secretNum {  
fmt.Println("too big! ")  
} else {  
fmt.Println("too small!")  
}  
}  

4. 完整

package main  
  
import (  
"fmt"  
"math/rand"  
"time"  
)  
  
func main() {  
maxNum := 100  
rand.Seed(time.Now().UnixNano()) //改版本了  
secretNum := rand.Intn(maxNum)  
fmt.Println("the secret number is: ", secretNum)  
//input the number  
var input int  
// loop  
for {  
fmt.Println("please enter the number:")  
fmt.Scanf("%d\n", &input) //输入char会显示0, 注意需要加\n，因为会读取换行符  
fmt.Println("your number is:", input)  
// if else  
if input == secretNum {  
fmt.Println("good guess! ")  
break  
} else if input > secretNum {  
fmt.Println("too big! ")  
} else {  
fmt.Println("too small!")  
}  
}  
}  

在线词典

• 抓包, http
• json

1. 翻译网站，彩云小译

• 检查--网络--dict--复制curl(bash)

2. curl--code
3. 修改部分代码，如结构体--json, 最后得到的json--结构体输出
4. json--struct

package main  
  
import (  
"bytes"  
"encoding/json"  
"fmt"  
"io"  
"log"  
"net/http"  
"os"  
)  
  
type DictRequest struct {  
TransType string `json:"trans_type"`  
Source string `json:"source"`  
UserID string `json:"user_id"`  
}  
  
type AutoGenerated struct {  
Rc int `json:"rc"`  
Wiki struct {  
} `json:"wiki"`  
Dictionary struct {  
Prons struct {  
EnUs string `json:"en-us"`  
En string `json:"en"`  
} `json:"prons"`  
Explanations []string `json:"explanations"`  
Synonym []string `json:"synonym"`  
Antonym []string `json:"antonym"`  
WqxExample [][]string `json:"wqx_example"`  
Entry string `json:"entry"`  
Type string `json:"type"`  
Related []interface{} `json:"related"`  
Source string `json:"source"`  
} `json:"dictionary"`  
}  
  
func query(word string) {  
client := &http.Client{} //创建请求头  
//var data = strings.NewReader(`{"trans_type":"en2zh","source":"good"}`)  
request := DictRequest{TransType: "en2zh", Source: word}  
buf, err := json.Marshal(request)  
if err != nil {  
log.Fatal(err)  
}  
var data = bytes.NewReader(buf)  
req, err := http.NewRequest("POST", "https://api.interpreter.caiyunai.com/v1/dict", data)  
if err != nil {  
log.Fatal(err)  
}  
//设置请求头  
req.Header.Set("authority", "api.interpreter.caiyunai.com")  
req.Header.Set("accept", "application/json, text/plain, */*")  
req.Header.Set("accept-language", "zh-CN,zh;q=0.9,en;q=0.8,en-GB;q=0.7,en-US;q=0.6")  
req.Header.Set("app-name", "xy")  
req.Header.Set("content-type", "application/json;charset=UTF-8")  
req.Header.Set("device-id", "178cf89dd85fcb0a88c3f7c0521eb3a2")  
req.Header.Set("origin", "https://fanyi.caiyunapp.com")  
req.Header.Set("os-type", "web")  
req.Header.Set("os-version", "")  
req.Header.Set("referer", "https://fanyi.caiyunapp.com/")  
req.Header.Set("sec-ch-ua", `"Not/A)Brand";v="99", "Microsoft Edge";v="115", "Chromium";v="115"`)  
req.Header.Set("sec-ch-ua-mobile", "?0")  
req.Header.Set("sec-ch-ua-platform", `"Windows"`)  
req.Header.Set("sec-fetch-dest", "empty")  
req.Header.Set("sec-fetch-mode", "cors")  
req.Header.Set("sec-fetch-site", "cross-site")  
req.Header.Set("user-agent", "Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/115.0.0.0 Safari/537.36 Edg/115.0.1901.183")  
req.Header.Set("x-authorization", "token:qgemv4jr1y38jyq6vhvi")  
resp, err := client.Do(req) //发起请求  
if err != nil {  
log.Fatal(err)  
}  
defer resp.Body.Close()  
bodyText, err := io.ReadAll(resp.Body) //读取响应  
if err != nil {  
log.Fatal(err)  
}  
//fmt.Printf("%s\n", bodyText)  
var dictResponse AutoGenerated  
err = json.Unmarshal(bodyText, &dictResponse)  
if err != nil {  
log.Fatal(err)  
}  
if resp.StatusCode != 200 {  
log.Fatal("bad statusCode")  
}  
  
//fmt.Printf("%#v\n", dictResponse)  
fmt.Println(word, "pron: ", dictResponse.Dictionary.Prons.En)  
for _, items := range dictResponse.Dictionary.Explanations {  
fmt.Println(items)  
}  
}  
  
func main() {  
if len(os.Args) != 2 {  
fmt.Printf("wrong args")  
os.Exit(1)  
}  
word := os.Args[1]  
query(word)  
}  

socks代理

• 第一阶段：客户端登录socks5
• 第二阶段：客户端发送请求，socks5连接服务器，成功后告诉客户端
• 第三阶段：客户端、socks5、服务器读写数据

1. 实现一个简单的echo服务器，用nc命令作为客户端