PHP: File downloader function - Downloading files in chunks.

downloadFileChunks.php

<?php
/**
 * Download helper to download files in chunks and save it.
 * 
 * @author Syed I.R <[email protected]>
 * @link https://github.com/irazasyed
 * 
 * @param  string  $srcName      Source Path/URL to the file you want to download
 * @param  string  $dstName      Destination Path to save your file
 * @param  integer $chunkSize    (Optional) How many bytes to download per chunk (In MB). Defaults to 1 MB.
 * @param  boolean $returnbytes  (Optional) Return number of bytes saved. Default: true
 * 
 * @return integer               Returns number of bytes delivered.
 */
function downloadFile($srcName, $dstName, $chunkSize = 1, $returnbytes = true) {
  $chunksize = $chunkSize*(1024*1024); // How many bytes per chunk
  $data = '';
  $bytesCount = 0;
  $handle = fopen($srcName, 'rb');
  $fp = fopen($dstName, 'w');
  if ($handle === false) {
    return false;
  }
  while (!feof($handle)) {
    $data = fread($handle, $chunksize);
    fwrite($fp, $data, strlen($data));
    if ($returnbytes) {
        $bytesCount += strlen($data);
    }
  }
  $status = fclose($handle);
  fclose($fp);
  if ($returnbytes && $status) {
    return $bytesCount; // Return number of bytes delivered like readfile() does.
  }
  return $status;
}

/** ------------------------------------------
 *  Function Usage
 *  ------------------------------------------
 */
$bytes = downloadFile('http://wordpress.org/latest.zip', 'latest.zip');