Go Web 开发核心基础：HTTP 协议与实战指南 | 极客日志

Go Web 开发核心基础：HTTP 协议与实战指南 | 极客日志

import (
    _ "github.com/go-sql-driver/mysql"
    "github.com/jmoiron/sqlx"
)

// 核心步骤
DB, err := sqlx.Open("mysql", "root:password@tcp(localhost:3306)/goweb?parseTime=true&loc=Local")
if err != nil {
    panic(err)
}
err = DB.Ping()

// 定义语句
queryCreate := "INSERT INTO user (id, name) VALUES (?, ?)"
queryDelete := "DELETE FROM user WHERE id = ?"
queryUpdate := "UPDATE user SET name = ? WHERE id = ?"
queryQuery := "SELECT * FROM user"

// 执行增删改
_, err := DB.Exec(queryCreate, 1, "白小纯")
_, err = DB.Exec(queryDelete, 1)
_, err = DB.Exec(queryUpdate, "夜藏", 1)

// 查询
rows, err := DB.Query(queryQuery)
for rows.Next() {
    var id int
    var name string
    rows.Scan(&id, &name)
}

func handleCookie(w http.ResponseWriter, r *http.Request) {
    // 设置 Cookie
    cookie := &http.Cookie{
        Name:   "session_id",
        Value:  "cookie_value",
        Expires: time.Now().Add(time.Hour),
    }
    http.SetCookie(w, cookie)

    // 获取单个 Cookie
    c, err := r.Cookie("session_id")
    if err == nil {
        fmt.Fprintf(w, "%s %s %v", c.Name, c.Value, c.Expires)
    }

    // 循环获取所有 Cookie
    cs := r.Cookies()
    for _, co := range cs {
        fmt.Println(co.Name, co.Value)
    }
}

func handleTemplate(w http.ResponseWriter, r *http.Request) {
    add := template.FuncMap{"add": AddFunc}
    t := template.New("index").Funcs(add)
    t, _ = t.ParseFiles("new_add")
    t.Execute(w, nil)
}

{{add 0 0}}

func handleUpload(w http.ResponseWriter, r *http.Request) {
    // 解析 multipart 表单
    err := r.ParseMultipartForm(32 << 20) // 限制 32MB
    if err != nil {
        return
    }
    
    f, _, err := r.FormFile("photo")
    if err != nil {
        return
    }
    defer f.Close()

    b, _ := io.ReadAll(f)
    err = os.WriteFile("/tmp/photo.jpg", b, 0777)
    if err != nil {
        fmt.Println("保存失败")
    }
}

<form action="/upload" enctype="multipart/form-data" method="post">
    <input type="file" name="photo">
    <button type="submit">上传</button>
</form>

func handleDownload(w http.ResponseWriter, r *http.Request) {
    filename := r.FormValue("filename")
    data, err := os.ReadFile(filename)
    if err != nil {
        return
    }

    h := w.Header()
    h.Set("Content-Type", "application/octet-stream")
    h.Set("Content-Disposition", "attachment; filename="+filename)
    w.Write(data)
}

<a href="/download?filename=file.png">点击下载</a>

type MyHandler struct{}

func (m MyHandler) ServeHTTP(w http.ResponseWriter, r *http.Request) {
    // 统一处理逻辑
}

func main() {
    server := http.Server{
        Addr:    "localhost:8888",
        Handler: MyHandler{},
    }
    server.ListenAndServe()
}

func TestHandler(w http.ResponseWriter, r *http.Request) {
    // 处理逻辑
}

func main() {
    server := http.Server{
        Addr: "localhost:8888",
    }
    http.HandleFunc("/url", TestHandler)
    server.ListenAndServe()
}