青训Day1：走进Go语言｜青训营笔记

这是我参与「第五届青训营 」伴学笔记创作活动的第 1 天。

1. 什么是Go语言

字节跳动为什么全面拥抱Go语言？

1. Python性能问题
2. C++不太适合在线Web业务
3. 早期团队非Java背景
4. Go性能较好
5. 部署简单，学习成本低
6. 内部RPC和HTTP框架的推广

2. 基础语法

1. 字符串是内置类型，可以通过“+”拼接，可以通过“=”比较；
2. 变量声明: 1）var name [int] = xxx
   2) name := xxx
3. if else条件不加()，必须加{}
4. 只有for循环
5. switch不需要加break
6. 数组长度固定，业务中更常用切片
7. 切片长度可变 s := make([]string, 3)
8. m := make(map[string]int)，无序
9. range
10. func add(a int, b int) int {}
11. pointer: n *int
12. type user struct {}
13. func (u user) add() int {}
14. 错误处理: err error
15. 字符串操作
16. 字符串格式化 fmt.Printf("s=%v\n", s)
17. JSON处理: 结构体第一个字母大写 buf, err = json.Marshal(a)
    err = json.Unmarshal(buf, &b)
18. 时间处理: time.Now()
19. 进程信息: os.Args获取命令行参数。
    os.Getenv("PATH")) os.Setenv("AA", "BB") buf, err := exec.Command()快速启动子进程

3. Go语言实战案例

1. 猜数字游戏 使用Scanf简化输入：

package main

import (
	"fmt"
	"math/rand"
	"time"
)

func main() {
	maxNum := 100
	rand.Seed(time.Now().UnixNano())
	secretNumber := rand.Intn(maxNum)
	// fmt.Println("The secret number is ", secretNumber)

	var guess int

	fmt.Println("Please input your guess")
	for {
		_, err := fmt.Scanf("%d", &guess)
		if err != nil {
			fmt.Println("An error occured while reading input. Please try again", err)
			continue
		}

		fmt.Println("You guess is", guess)
		if guess > secretNumber {
			fmt.Println("Your guess is bigger than the secret number. Please try again")
		} else if guess < secretNumber {
			fmt.Println("Your guess is smaller than the secret number. Please try again")
		} else {
			fmt.Println("Correct, you Legend!")
			break
		}
	}
}

2. 在线词典介绍 Curl代码生成: curlconverter.com/#go
   JSON转Golang Struct: oktools.net/json2go

package main

import (
	"bytes"
	"encoding/json"
	"fmt"
	"io/ioutil"
	"log"
	"net/http"
	"os"
)

type DictRequest struct {
	TransType string `json:"trans_type"`
	Source    string `json:"source"`
	UserID    string `json:"user_id"`
}

type DictResponse struct {
	Rc   int `json:"rc"`
	Wiki struct {
		KnownInLaguages int `json:"known_in_laguages"`
		Description     struct {
			Source string      `json:"source"`
			Target interface{} `json:"target"`
		} `json:"description"`
		ID   string `json:"id"`
		Item struct {
			Source string `json:"source"`
			Target string `json:"target"`
		} `json:"item"`
		ImageURL  string `json:"image_url"`
		IsSubject string `json:"is_subject"`
		Sitelink  string `json:"sitelink"`
	} `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{}
	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)
	}
	req.Header.Set("Connection", "keep-alive")
	req.Header.Set("DNT", "1")
	req.Header.Set("os-version", "")
	req.Header.Set("sec-ch-ua-mobile", "?0")
	req.Header.Set("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/99.0.4844.51 Safari/537.36")
	req.Header.Set("app-name", "xy")
	req.Header.Set("Content-Type", "application/json;charset=UTF-8")
	req.Header.Set("Accept", "application/json, text/plain, */*")
	req.Header.Set("device-id", "")
	req.Header.Set("os-type", "web")
	req.Header.Set("X-Authorization", "token:qgemv4jr1y38jyq6vhvi")
	req.Header.Set("Origin", "https://fanyi.caiyunapp.com")
	req.Header.Set("Sec-Fetch-Site", "cross-site")
	req.Header.Set("Sec-Fetch-Mode", "cors")
	req.Header.Set("Sec-Fetch-Dest", "empty")
	req.Header.Set("Referer", "https://fanyi.caiyunapp.com/")
	req.Header.Set("Accept-Language", "zh-CN,zh;q=0.9")
	req.Header.Set("Cookie", "_ym_uid=16456948721020430059; _ym_d=1645694872")
	resp, err := client.Do(req)
	if err != nil {
		log.Fatal(err)
	}
	defer resp.Body.Close()
	bodyText, err := ioutil.ReadAll(resp.Body)
	if err != nil {
		log.Fatal(err)
	}
	if resp.StatusCode != 200 {
		log.Fatal("bad StatusCode:", resp.StatusCode, "body", string(bodyText))
	}
	var dictResponse DictResponse
	err = json.Unmarshal(bodyText, &dictResponse)
	if err != nil {
		log.Fatal(err)
	}
	fmt.Println(word, "UK:", dictResponse.Dictionary.Prons.En, "US:", dictResponse.Dictionary.Prons.EnUs)
	for _, item := range dictResponse.Dictionary.Explanations {
		fmt.Println(item)
	}
}

func main() {
	if len(os.Args) != 2 {
		fmt.Fprintf(os.Stderr, `usage: simpleDict WORD
example: simpleDict hello
		`)
		os.Exit(1)
	}
	word := os.Args[1]
	query(word)
}

3. SOCKS5代理