Stream a mp3 file using php when you need to protect the file

sream_function.php

<?php
  function zcast_stream($file, $content_type = 'application/octet-stream') {
  @error_reporting(0);

  // Make sure the files exists, otherwise we are wasting our time
  if (!file_exists($file)) {
    header("HTTP/1.1 404 Not Found");
    exit;
  }

  // Get file size
  $filesize = sprintf("%u", filesize($file));

  // Handle 'Range' header
  if(isset($_SERVER['HTTP_RANGE'])){
    $range = $_SERVER['HTTP_RANGE'];
  }elseif($apache = apache_request_headers()){
    $headers = array();
    foreach ($apache as $header => $val){
      $headers[strtolower($header)] = $val;
    }
    if(isset($headers['range'])){
      $range = $headers['range'];
    }
    else $range = FALSE;
  } else $range = FALSE;

  //Is range
  if($range){
    $partial = true;
    list($param, $range) = explode('=',$range);
    // Bad request - range unit is not 'bytes'
    if(strtolower(trim($param)) != 'bytes'){
      header("HTTP/1.1 400 Invalid Request");
      exit;
    }
    // Get range values
    $range = explode(',',$range);
    $range = explode('-',$range[0]);
    // Deal with range values
    if ($range[0] === ''){
      $end = $filesize - 1;
      $start = $end - intval($range[0]);
    } else if ($range[1] === '') {
      $start = intval($range[0]);
      $end = $filesize - 1;
    }else{
      // Both numbers present, return specific range
      $start = intval($range[0]);
      $end = intval($range[1]);
      if ($end >= $filesize || (!$start && (!$end || $end == ($filesize - 1))))       $partial = false; // Invalid range/whole file specified, return whole file
    }
    $length = $end - $start + 1;
  }
  // No range requested
  else $partial = false;

  // Send standard headers
  header("Content-Type: $content_type");
  header("Content-Length: $length");
  header('Accept-Ranges: bytes');
  header('Connection: keep-alive');


  // send extra headers for range handling...
  if ($partial) {

    header('HTTP/1.1 206 Partial Content');

    header("Content-Range: bytes $start-$end/$filesize");
    if (!$fp = fopen($file, 'rb')) {
      header("HTTP/1.1 500 Internal Server Error");
      exit;
    }
    if ($start) fseek($fp,$start);
    print(fread($fp,$length));
    fclose($fp);
  }
  //just send the whole file
  else readfile($file);
  exit;
}