生成签名，随机字符串，XML转为数组，数组转XML，json封装，获取IP地址

/*
 * ******生成签名*********
 */
private function getSign($params)
{
    ksort($params); //将参数数组按照参数名ASCII码从小到大排序
    foreach ($params as $key => $item) {
        if (!empty($item)) {  //剔除参数值为空的参数
            $newArr[] = $key . '=' . $item; // 整合新的参数数组
        }
    }
    $stringA = implode("&", $newArr);  //使用 & 符号连接参数
    $stringSignTemp = $stringA . "&key=" . "key";
    // key是在商户平台API安全里自己设置的
    $stringSignTemp = hash_hmac("sha256",$stringSignTemp,"key"); //将字符串进行MD5加密或hash_hmac加密
    $sign = strtoupper($stringSignTemp); //将所有字符转换为大写
    return $sign;
}

/*
* ***生成随机字符串,微信所需参数！
*/
function rand_code()
{
    $str = '0123456789abcdefghijklmnopqrstuvwxyzABCDEFGHIJKLMNOPQRSTUVWXYZ';//62个字符
    $str = str_shuffle($str);
    $str = substr($str, 0, 32);
    return $str;
}

/*
 * ******传输给微信的参数要组成xml格式发送，传入参数数组
*/
public function ToXml($data = array())
{
    if (!is_array($data) || count($data) <= 0) {
        return '数组异常';
    }
    $xml = "<xml>";
    foreach ($data as $key => $val) {
        if (is_numeric($val)) {
            $xml .= "<" . $key . ">" . $val . "</" . $key . ">";
        } else {
            $xml .= "<" . $key . "><![CDATA[" . $val . "]]></" . $key . ">";
        }
    }
    $xml .= "</xml>";
    return $xml;
}

/*
 * ******将xml数据转换为数组，接收微信返回数据时用到*********
 */
public function FromXml($xml)
{
    if (!$xml) {
        echo "xml数据异常！";
    }
    //将XML转为array
    //禁止引用外部xml实体
    libxml_disable_entity_loader(true);
    $data = json_decode(json_encode(simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA)), true);

    return $data;
}

/**
 * api 数据返回
 * @param  [int] $code [结果码 200:正常/4**数据问题/5**服务器问题]
 * @param  [string] $msg  [接口要返回的提示信息]
 * @param  [array]  $data [接口要返回的数据]
 * @return [string]       [最终的json数据]
 */

 function return_msg($code, $msg = '', $data = []) {
        /*********** 组合数据  ***********/
        $return_data['code'] = $code;
        $return_data['msg']  = $msg;
        if(empty($data)){
            $return_data['data'] = "";
        }else{
            $return_data['data'] = $data;
        }
        /*********** 返回信息并终止脚本  ***********/
//        echo json_encode($return_data,JSON_UNESCAPED_UNICODE);die;
        echo str_replace(':null',':""',json_encode($return_data,JSON_UNESCAPED_UNICODE));die;//JSON_UNESCAPED_UNUCODE 禁止中文转换
    }

/*
 * 获取当前用户注册的ip
 */

function get_client_ip($type = 0)
{
    $type = $type ? 1 : 0;
    static $ip = NULL;
    if ($ip !== NULL) return $ip[$type];
    if (isset($_SERVER['HTTP_X_FORWARDED_FOR'])) {
        $arr = explode(',', $_SERVER['HTTP_X_FORWARDED_FOR']);
        $pos = array_search('unknown', $arr);
        if (false !== $pos) unset($arr[$pos]);
        $ip = trim($arr[0]);
    } elseif (isset($_SERVER['HTTP_CLIENT_IP'])) {
        $ip = $_SERVER['HTTP_CLIENT_IP'];
    } elseif (isset($_SERVER['REMOTE_ADDR'])) {
        $ip = $_SERVER['REMOTE_ADDR'];
    }
    // IP地址合法验证
    $long = sprintf("%u", ip2long($ip));
    $ip = $long ? array($ip, $long) : array('0.0.0.0', 0);
    return $ip[$type];
}