PHP's "walking micro channel data" analysis processing

Scenario Description:

Recently the company was doing "walking through the micro-channel rank, receive reward-related activities" feature, middle, naturally related to the WeChat walking data related decryption operation, function has been done, to sum up. Note that, hereinafter, relates only to the backend data processing, how to obtain, there is provided by the front end!

First, the basic part of the preparation for the relevant parameters

/**
 * 每次进入小程序，把前端推送的走步数据，存入到【组成员表】
 */
public function save_member_steps()
{
    $request = $this->get;
    //$request['step_data'] = "M4OKJ5Q6yR0dwVtDX/P+/DJJuFs1oWmjZ9I8h8HJFSn6WslrGcxUXpXxq46W1g28AAaDGAf0z79zycv/g5VqY";
    //$request['iv'] = "QUzF4rjjsKhakdjjE8Px9w==";
    //$request['openid'] = "oqahZ5LbBsdf099ikjdKoruXtPI";

    // 获取相关的参数，并判断
    $userid = isset($request['userid']) ? $request['userid'] : 0;
    if(!$userid){
        return $this->export->get_export($this->errors[506]['error_code'], $this->errors, []);
    }
    // 从微信获取步数
    $step_data_str = isset($request['step_data']) && !empty($request['step_data']) ? strval($request['step_data']) : '';
    if(!$step_data_str){
        return $this->export->get_export($this->errors[512]['error_code'], $this->errors, []);
    }
    // 获取步数微信端参数
    $iv = !empty($request['iv']) ? strval($request['iv']) : '';
    // 获取步数微信端参数
    $openid = !empty($request['openid']) ? strval($request['openid']) : '';
    $this->load->dao('active_step_dao');
    // 解密微信端获取步数数据
    $step_datas = $this->process_wx_step_data($openid, $iv, $step_data_str);
    // 步数数据更新到user_step_everyday_log表
    $update_everyday_log = $this->update_step_log_data($userid, $step_datas);
    return  $update_everyday_log ? true : false;
}

/**
 * 获取用户的走步数据，更新到成员表
 * @param $openid
 * @param $iv
 * @param $step_data_str
 * @return array
 */
public function process_wx_step_data($openid, $iv, $step_data_str)
{
    // 从微信记录里获取数据，比对一下，是否正确，如果不正确，更新【组成员步数】，团表里的总步数累加
    $this->load->service('user_wechat_service');
    $step_data = $this->user_wechat_service->auth_step_data($openid, $iv, $step_data_str, 1);
    $stepInfoList = [];
    if(isset($step_data['stepInfoList']) && !empty($step_data['stepInfoList'])){
        $stepInfoList = $step_data['stepInfoList'];
        foreach ($stepInfoList as $key=>$val) {
            $stepInfoList[$key]['time'] = date('Y-m-d', $val['timestamp']);
        }
        $stepInfoList = array_column($stepInfoList, null, 'time');
    }
    return $stepInfoList;
}

Second, the core part, responsible for the data processing micro-channel end

/**
 * 获取微信端用户【走步】数据
 * @param $openid 用户小程序openid
 * @param $iv 小程序返回的iv字段
 * @param $step_data_str 小程序返回的走步加密字段
 * @param $plat_type 1 用户端  2 教练端
 * @return array
 */
public function auth_step_data($openid, $iv, $step_data_str, $plat_type)
{
    if (empty($openid) || empty($iv) || empty($step_data_str) || empty($plat_type)) {
        return [];
    }
    $decrypt_data = $this->_get_encrypted_data($openid, $step_data_str, $iv, $plat_type);
    return $decrypt_data;
}

/**
 * 对微信加密的数据进行解密
 * @param $openid
 * @param $encrypted_data
 * @param $iv
 * @return string
 */
private function _get_encrypted_data($openid, $encrypted_data, $iv, $plat_type)
{
    $result = '';
    if (empty($openid) || empty($encrypted_data) || empty($iv) || empty($plat_type)) {
        return $result;
    }
    $this->load->dao('user_wechat_dao');
    $user = $this->user_wechat_dao->get_userid($openid, $plat_type);
    if (empty($user)) {
        return $result;
    }
    $this->load->config('dict/wechat_config');
    $dict_name = $plat_type == self::PLAT_TYPE_USER ? 'dict_wechat_user' : 'dict_wechat_coach';
    $app_config = $this->config->item($dict_name);
    $result = $this->_decrypt_data($app_config['app_id'], $user['sessionkey'], $encrypted_data, $iv);
    return $result;
}

/**
 * 解密数据 
 * @desc VALIDATE_LEN_NUM = 24;
 * @param $appid
 * @param $session_key
 * @param $encrypted_data
 * @param $iv
 * @return mixed|string
 */
private function _decrypt_data($appid, $session_key, $encrypted_data, $iv)
{
    $result = '';
    if (strlen($session_key) != self::VALIDATE_LEN_NUM || strlen($iv) != self::VALIDATE_LEN_NUM) {
        return $result;
    }

    $aes_key = base64_decode(str_replace(' ','+',$session_key));
    $aes_iv = base64_decode(str_replace(' ','+',$iv));
    $aes_cipher = base64_decode(str_replace(' ','+',$encrypted_data));
    $data = openssl_decrypt($aes_cipher, "AES-128-CBC", $aes_key, 1, $aes_iv);
    $data = json_decode($data, TRUE);

    if (empty($data)) {
        return $result;
    }
    if (!isset($data['watermark']['appid']) || $data['watermark']['appid'] != $appid) {
        return $result;
    }
    return $data;
}

Third, write the last words

Some parts of the code belongs to the configuration file, posted inconvenience, but does not affect the look. Micro-letters "walking data" analysis process, the key point is "decrypted data", this is a difficult, involving a number of functions, to be understood that a careful analysis, there is no other!