php Blob url to directory

Question

throught ajax send a blob url

var blob = new Blob([content], { type: 'text/html; charset=utf-8' });
var urlBlob = URL.createObjectURL(blob);

$.ajax({
    url: url,
    data: { 
        'blob': urlBlob
    },
    type: 'POST',
    dataType: 'json',
    success: function (data) {
       alert("ok");
    }
    , error: function () {
        alert('error');
    }
});

in php i read this string blob:http://localhost:8888/4eca0076-33c8-42ab-bd96-11055dcf800f

now i'd like to save in a dir.... I tried

$file = fopen($filepath, "w");
fwrite($file, base64_decode($blob));
fclose($file);

OR

move_uploaded_file(base64_decode($blob), $filepath);

but write a strange characters

file_put_contents($filepath, base64_decode($blob));

don't works

do you ha ve idea?