Golang Web JSON数据解析与验证技巧

type UserRequest struct {
    Name     string `json:"name"`
    Email    string `json:"email"`
    Age      int    `json:"age"`
    Password string `json:"password"`
}

var req UserRequest
err := json.NewDecoder(r.Body).Decode(&req)
if err != nil {
    http.Error(w, "Invalid JSON", http.StatusBadRequest)
    return
}

go get github.com/go-playground/validator/v10

type UserRequest struct {
    Name     string `json:"name" validate:"required,min=2,max=50"`
    Email    string `json:"email" validate:"required,email"`
    Age      int    `json:"age" validate:"gte=0,lte=150"`
    Password string `json:"password" validate:"required,min=6"`
}

validate := validator.New()
err = validate.Struct(req)
if err != nil {
    for _, err := range err.(validator.ValidationErrors) {
        http.Error(w, fmt.Sprintf("Field %s is invalid: %s", err.Field(), err.Tag()), http.StatusBadRequest)
        return
    }
}

type UserUpdateRequest struct {
    Name  string  `json:"name,omitempty"`
    Age   *int    `json:"age,omitempty"` // 使用指针区分“未提供”和“零值”
}

if req.Age != nil {
    fmt.Printf("User age updated to: %d", *req.Age)
}

type ErrorResponse struct {
    Error string `json:"error"`
}

func writeError(w http.ResponseWriter, message string, status int) {
    w.Header().Set("Content-Type", "application/json")
    w.WriteHeader(status)
    json.NewEncoder(w).Encode(ErrorResponse{Error: message})
}

if err != nil {
    writeError(w, "Invalid request data", http.StatusBadRequest)
    return
}