Comment écrire une interface de rappel php

<?xml version="1.0" encoding="utf-8"?>
    <returnData>
        <type>1</type>
        <count>2</count>
        <list>
            <allRet>
                <id>1529051684657847</id>
                <mobile>187********</mobile>
                <status>0</status>
                <userId>zzzppp</userId>
            </allRet>
            <allRet>
                <id>1529051612347847</id>
                <mobile>137********</mobile>
                <status>1</status>
                <userId>wwwhhh</userId>
            </allRet>
        </list>
    </returnData>

//PHP接收回调地址操作
public function backAction(){
//模拟获取接收的数据
$contents = $this->getData();    //本地模拟接口获取到的数据
//$contents = file_get_contents('php://input');
$data = $contents ? $this->_xmlToArray($contents) : array();
//写回滚日志
$filePath = APP_PATH."/data/log/";
$this->createDirectory($filePath);    //目录不存在，则创建
$fileName = $filePath."back.txt";
file_put_contents( $fileName, date('Ymd H:i:s')."\r\n".(json_encode($data))."\r\n", FILE_APPEND | LOCK_EX);
//var_export($data);die;
$cnt = 0;
$result = $data['list']['allRet'];
/**根据回调结果处理我们数据库的逻辑*/
//START
foreach ($result as $k => $v){ //在循环中[根据唯一标识ID]处理自己数据了的逻辑
    $userMobile = $v['mobile'];
    if($v['status'] == 1 ){
        
    }else{
        
    }
    $cnt ++;
}
//END
if( $cnt == $data['count'] ){
    file_put_contents( $fileName, date('Ymd H:i:s')."\r\n".(json_encode($data))."\r\n", FILE_APPEND | LOCK_EX);
    //写结果日志
    exit('SUCCESS');    //响应第三方[在回调中返回结果，告诉人家自己是否回调成功，否则人家可能会回调N次]
}else{
    file_put_contents( $fileName, date('Ymd H:i:s')."\r\n".(json_encode($data))."\r\n", FILE_APPEND | LOCK_EX);
    //写结果日志
    exit('ERROR');
}
}
//XML格式化成数组
function _xmlToArray($xml){
libxml_disable_entity_loader(true);
$xmlstring = simplexml_load_string($xml, 'SimpleXMLElement', LIBXML_NOCDATA);
$val = json_decode(json_encode($xmlstring),true);
return $val;
}
//递归创建目录[在linux下要有创建目录的权限才能创建目录 chmod -R 777 /var/data/log ]
public function createDirectory( $dir ){
return  is_dir ( $dir ) or $this->createDirectory(dirname( $dir )) and  mkdir ( $dir , 0777);
}
public function getData(){
$xml = &#39;<?xml version="1.0" encoding="utf-8"?>
            <returnData>
                <type>1</type>
                <count>2</count>
                <list>
                    <allRet>
                        <id>1529051684657847</id>
                        <mobile>187********</mobile>
                        <status>0</status>
                        <userId>zzzppp</userId>
                    </allRet>
                    <allRet>
                        <id>1529051612347847</id>
                        <mobile>137********</mobile>
                        <status>1</status>
                        <userId>wwwhhh</userId>
                    </allRet>
                </list>
        </returnData>&#39;;
return $xml;
}