Golang统一解析Web请求参数详解

type LoginRequest struct {
    Username string `json:"username" form:"username" query:"username"`
    Password string `json:"password" form:"password" query:"password"`
}

func ParseRequest(r *http.Request, target interface{}) error {
    // 解析查询参数
    if r.URL != nil {
        queryValues := r.URL.Query()
        setFromValues(target, queryValues, "query")
    }

    // 解析表单数据
    if err := r.ParseForm(); err != nil {
        return err
    }
    setFromValues(target, r.Form, "form")

    // 解析JSON Body
    if strings.Contains(r.Header.Get("Content-Type"), "application/json") {
        body, _ := io.ReadAll(r.Body)
        if len(body) > 0 {
            if err := json.Unmarshal(body, target); err != nil {
                return err
            }
            r.Body = io.NopCloser(bytes.NewBuffer(body)) // 重置Body供后续读取
        }
    }

    return nil
}

type RequestBinder interface {
    Bind(*http.Request) error
}

func HandleLogin(w http.ResponseWriter, r *http.Request) {
    var req LoginRequest
    if err := ParseRequest(r, &req); err != nil {
        http.Error(w, "参数解析失败", http.StatusBadRequest)
        return
    }

    // 调用业务逻辑
    result := loginService(req.Username, req.Password)
    json.NewEncoder(w).Encode(result)
}

type LoginRequest struct {
    Username string `form:"username" validate:"required,email"`
    Password string `form:"password" validate:"required,min=6"`
}