获取JSON文件并推送PHP

Question

In my data storage folder is a JSON file. I save the device id to the local storage of the broswer:

//Store deviceID in local storage on button click
function store(){
    var inputDeviceID= document.getElementById("deviceID");
    localStorage.setItem("deviceID", inputDeviceID.value);
}

I get the device id with a javascript function and push it with ajax into my php script to load the corresponsing data:

function localstoragecheck(){
    if (localStorage.getItem("deviceID") === null) {
        //alert('no');
    }
    else {
        //alert('yes');

        var deviceIDcookie = localStorage.getItem("deviceID");

        $.ajax({
            url: '/',
            data: {'deviceID': deviceIDcookie},
            dataType: 'jsonp',
            complete : function(){
               // alert(this.url)
               $.getJSON("/sigfoxdata/" + deviceIDcookie + ".json", function(json) {
                   console.log(json); // this will show the info it in firebug console
               });
            }
        });
    }
}

PHP code for searching the json file and decode it:

$FOLDER = '../sigfoxdata/';
$dir = scandir($FOLDER);
$file = $_GET['deviceID'].'.json' ?: 'DEMO.json';
$fileUrl = $FOLDER.$file;

$file = fopen($fileUrl, "rip");
$lines =  fread($file, filesize($fileUrl));
$data = json_decode($lines)->{'data'};

But this is not working, how can I get data from the ajax request in the PHP script?