Golang如何实现表单提交与验证_Golang Web表单验证与数据处理实践

<form method="POST" action="/submit">
  <input type="text" name="username" />
  <input type="email" name="email" />
  <input type="password" name="password" />
  <button type="submit">提交</button>
</form>

func submitHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method != "POST" {
        http.Error(w, "方法不被允许", http.StatusMethodNotAllowed)
        return
    }

    if err := r.ParseForm(); err != nil {
        http.Error(w, "解析表单失败", http.StatusBadRequest)
        return
    }

    username := r.PostForm.Get("username")
    email := r.PostForm.Get("email")
    password := r.PostForm.Get("password")

    // 接下来进行验证
}

type UserForm struct {
    Username string `validate:"required,min=3,max=20"`
    Email    string `validate:"required,email"`
    Password string `validate:"required,min=6"`
}

func validateForm(form UserForm) map[string]string {
    validate := validator.New()
    errors := make(map[string]string)

    if err := validate.Struct(form); err != nil {
        for _, err := range err.(validator.ValidationErrors) {
            field := err.Field()
            tag := err.Tag()
            switch tag {
            case "required":
                errors[field] = field + " 是必填项"
            case "min":
                errors[field] = field + " 长度不足"
            case "email":
                errors[field] = "邮箱格式不正确"
            }
        }
    }
    return errors
}

func submitHandler(w http.ResponseWriter, r *http.Request) {
    if r.Method != "POST" {
        http.Error(w, "方法不被允许", http.StatusMethodNotAllowed)
        return
    }

    if err := r.ParseForm(); err != nil {
        http.Error(w, "解析表单失败", http.StatusBadRequest)
        return
    }

    form := UserForm{
        Username: r.PostForm.Get("username"),
        Email:    r.PostForm.Get("email"),
        Password: r.PostForm.Get("password"),
    }

    if errs := validateForm(form); len(errs) > 0 {
        // 返回错误信息给前端（可渲染回模板或返回 JSON）
        w.Header().Set("Content-Type", "application/json")
        json.NewEncoder(w).Encode(errs)
        return
    }

    // 验证通过，执行业务逻辑（如存入数据库）
    fmt.Fprintf(w, "提交成功：用户名 %s，邮箱 %s", form.Username, form.Email)
}

data := struct {
    Errors map[string]string
    Form   UserForm
}{
    Errors: errs,
    Form:   form,
}
tmpl.Execute(w, data)