Ukladanie súborov na server v PHP

$data = file_get_contents('data.txt');
$data = json_decode($data ? : [] ;
array_push($data, get_post_meta( $id, '_sku', true ) );
file_put_contents('data.txt', json_encode(array_unique($data)));

var_dump( json_encode(array_unique($data)) );

/* citanie suboru */ 
$read = json_decode(file_get_contents('data.txt'));
print_r($read[0]);
print_r($read[1]);

alebo

foreach ($data as $item){
 echo $item;
}

/* ak súbor uz existuje */
if( ! is_file(data.txt) ){
  return // iba ak subor neexistuje
}

/*  mozeme pouzit aj  fwrite ak potrebujeme presnejsie zapisovanie */
   $myfile = fopen("data.txt", "w") or die("Unable to open file!");   //x  //x+  // citanie , dopisovanie...
   viac na https://www.php.net/manual/en/function.fopen
   fwrite($myfile, var_export($data, true) );
   fwrite($myfile, print_r($data), true );
   fclose($myfile);
   skratene fclose( fopen("data.txt", "x+") );

// zistenie prichadzajuceho postu
if ( !empty($_POST) ){
echo '<pre>';
print_r($_POST);
echo '</pre>';
}

$filename = 'output_' . date("Y-m-d-h:i:s") . '.png';  // name output file 
$filepath = 'saved_images/';  // folder for output images
$input = 'https://pbs.twimg.com/media/EKdH0WYXUAAlSgf.png';   // input

file_put_contents($filepath.$filename, file_get_contents($input)); // save(folder-filename, input )) 
echo $filepath.$filename;

$data = file_get_contents('data.txt');
$data = json_decode($data )? : [] ;
array_push($data, 'zamietnute ' . $position->status  . ' ' . $original_status . ' + ' . date('Y-m-d H:i:s'));  //. date('Y-m-d H:i:s')
file_put_contents('data.txt', json_encode($data));