php支持分块与断点续传文件下载功能代码

$dowmFile = dirname ( __FILE__ ) . '/Nokia - Always Here.mp3'; //要下载的文件，绝对或相对
$dowmName = 'Nokia - Always Here.mp3';
ob_start ();
getlocalfile ( $dowmFile, $dowmName );
flush ();
ob_flush ();
function getlocalfile($fname, $filename = '') {
  $fsize = filesize ( $fname );
  header ( 'Cache-Control: public' );
  header ( 'Pragma: public' );
  header ( 'Accept-Ranges: bytes' );
  header ( 'Connection: close' );
  header ( 'Content-Type: ' . MIMEType ( $fname ) );
  //header('Content-Type: application/octet-stream');
  if (isset ( $filename {0} )) {
    header ( 'Content-Disposition: attachment;filename=' . $filename );
  }
  if ($fp = @fopen ( $fname, 'rb' )) {
    $start = 0;
    $end = $fsize;
    $isRange = isset ( $_SERVER ['HTTP_RANGE'] ) && ($_SERVER ['HTTP_RANGE'] != '');
    if ($isRange) {
      preg_match ( '/^bytes=([0-9]*)-([0-9]*)$/i', $_SERVER ['HTTP_RANGE'], $match );
      $start = $match [1];
      $end = $match [2];
      $isset_start = isset ( $start {0} );
      $isset_end = isset ( $end {0} );
      if ($isset_start && $isset_end) {
        //分块下载
        if ($start >= $fsize || $start < 0 || $start > $end) {
          $start = 0;
          $end = $fsize;
        } else if ($end >= $fsize) {
          $end = $fsize - $start;
        } else {
          $end -= $start - 1;
        }
      } else if ($isset_start && ! $isset_end) {
        //指定位置到结束
        if ($start >= $fsize || $start < 0) {
          $start = 0;
          $end = $fsize;
        } else {
          $end = $fsize - $start;
        }
      } else if (! $isset_start && $isset_end) {
        //最后n个字节
        $end = $end > $fsize ? $fsize : $end;
        $start = $fsize - $end;
      } else {
        $start = 0;
        $end = $fsize;
      }
    }
    if ($isRange) {
      fseek ( $fp, $start );
      header ( 'HTTP/1.1 206 Partial Content' );
      header ( 'Content-Length: ' . $end );
      header ( 'Content-Ranges: bytes ' . $start . '-' . ($end + $start - 1) . '/' . $fsize );
    } else {
      header ( 'Content-Length: ' . $fsize );
    }
    if (function_exists ( 'fpassthru' ) && ($end + $start) == $fsize) {
      fpassthru ( $fp );
    } else {
      echo fread ( $fp, $end );
    }
  } else {
    header ( 'Content-Length: ' . $fsize );
    readfile ( $fname );
  }
  //@header("Content-Type: ".mime_content_type($fname));
}
function MIMEType($fname) {
  $fileSuffix = strtolower ( substr ( $fname, strrpos ( $fname, '.' ) + 1 ) );
  switch ($fileSuffix) {
    case 'avi' :
      return 'video/msvideo';
    case 'wmv' :
      return 'video/x-ms-wmv';
    case 'txt' :
      return 'text/plain';
    case 'htm' :
    case 'html' :
    case 'php' :
      return 'text/html';
    case 'css' :
      return 'text/css';
    case 'js' :
      return 'application/javascript';
    case 'json' :
    case 'xml' :
    case 'zip' :
    case 'pdf' :
    case 'rtf' :
    case 'tar' :
      return 'application/' . $fileSuffix;
    case 'swf' :
      return 'application/x-shockwave-flash';
    case 'flv' :
      return 'video/x-flv';
    case 'jpe' :
    case 'jpg' :
      return 'image/jpeg';
    case 'jpeg' :
    case 'png' :
    case 'gif' :
    case 'bmp' :
    case 'tiff' :
      return 'image/' . $fileSuffix;
    case 'ico' :
      return 'image/vnd.microsoft.icon';
    case 'tif' :
      return 'image/tiff';
    case 'svg' :
    case 'svgz' :
      return 'image/svg+xml';
    case 'rar' :
      return 'application/x-rar-compressed';
    case 'exe' :
    case 'msi' :
      return 'application/x-msdownload';
    case 'cab' :
      return 'application/vnd.ms-cab-compressed';
    case 'aif' :
      return 'audio/aiff';
    case 'mpg' :
    case 'mpe' :
    case 'mp3' :
      return 'audio/mpeg';
    case 'mpeg' :
    case 'wav' :
    case 'aiff' :
      return 'audio/' . $fileSuffix;
    case 'qt' :
    case 'mov' :
      return 'video/quicktime';
    case 'psd' :
      return 'image/vnd.adobe.photoshop';
    case 'ai' :
    case 'eps' :
    case 'ps' :
      return 'application/postscript';
    case 'doc' :
    case 'docx' :
      return 'application/msword';
    case 'xls' :
    case 'xlt' :
    case 'xlm' :
    case 'xld' :
    case 'xla' :
    case 'xlc' :
    case 'xlw' :
    case 'xll' :
      return 'application/vnd.ms-excel';
    case 'ppt' :
    case 'pps' :
      return 'application/vnd.ms-powerpoint';
    case 'odt' :
      return 'application/vnd.oasis.opendocument.text';
    case 'ods' :
      return 'application/vnd.oasis.opendocument.spreadsheet';
    default :
      if (function_exists ( 'mime_content_type' )) {
        $fileSuffix = mime_content_type ( $filename );
      } else {
        $fileSuffix = 'application/octet-stream';
      }
      return $fileSuffix;
      break;
  }
}