weixinrpc/sign.go

package weixinrpc

import (
	"crypto/md5"
	"encoding/hex"
	"encoding/json"
	"errors"
	"strconv"
	"strings"
	"time"

	"git.tetele.net/tgo/crypter"
)

/**
 * 签名
 */
func Sign(data string, salt string) string {

	var build strings.Builder

	build.WriteString(data)
	build.WriteString(salt)
	build.WriteString(DES_KEY)

	data_str := build.String()

	h := md5.New()
	h.Write([]byte(data_str))             // 需要加密的字符串
	return hex.EncodeToString(h.Sum(nil)) // 输出加密结果

}

/**
 * 验证签名
 */
func CheckSign(sign_str, data, salt string) bool {
	sign := Sign(data, salt)
	if strings.Compare(sign_str, sign) > -1 {
		return true
	}
	return false
}

/**
 * 解密
 */
func GetOrgData(res *Response) (string, error) {

	res_data := res.GetData()

	if res_data == "" {

		return "", errors.New("未收到收据")
	}

	time_int64, err := strconv.ParseInt(res.GetTime(), 10, 64)
	if err != nil {
		return "", err
	}

	now_int64 := time.Now().Unix()

	if now_int64-time_int64 > 10 || time_int64-now_int64 > 10 {
		//时间误差前后10秒，返回
		return "", errors.New("返回时间错误")
	}

	check_sign := CheckSign(res.GetSign(), res_data, res.GetTime())
	if !check_sign {
		return "", errors.New("返回数据签名错误")
	}

	//解密
	res_data_de := crypter.DesDe(res_data, DES_KEY)

	return res_data_de, nil
}

/**
 * 处理返回结果
 */
func HandleRes(res *Response) (*WxApiRes, error) {

	//解密
	res_data_de, err := GetOrgData(res)

	if err != nil {
		return nil, err
	}

	var res_arr WxApiRes

	err = json.Unmarshal([]byte(res_data_de), &res_arr)

	if err != nil {
		return nil, err
	}

	return &res_arr, nil
}