Invalid or unitialized Zip object

Question

if(isset($_POST['items'])) {
    // open zip
    $zip_path = 'downloadSelected/download.zip';
    $zip = new ZipArchive();

    if ($zip->open($zip_path, ZIPARCHIVE::CREATE | ZIPARCHIVE::OVERWRITE) !== TRUE) {
       die ("An error occurred creating your ZIP file.");
     }

     foreach ($_POST['items'] as $path) {
        // generate filename to add to zip
        $filepath = 'downloads/' . $path . '.zip';
        if (file_exists($filepath)) {
                $zip->addFile($filepath, $path . '.zip') or die ("ERROR: Could not add the file $filename");
        }
        else {
                die("File $filepath doesnt exit");
                }
        $zip->close();
       } }

I am getting Warning: ZipArchive::addFile() [function.ZipArchive-addFile]: Invalid or unitialized Zip object . what could be problem? I tried many methods but in vain. I am able to create and initiate download when I select one file. However, I get above error when I select more than one file.

Answer 1

The power of indenting correctly!

You are closing your zip file inside your loop.

If I re-format your code it becomes obvious.

Corrected code follows:

if(isset($_POST['items'])) {
  // open zip
  $zip_path = 'downloadSelected/download.zip';
  $zip = new ZipArchive();

  if ($zip->open($zip_path, ZIPARCHIVE::CREATE | ZIPARCHIVE::OVERWRITE) !== TRUE) {
    die ("An error occurred creating your ZIP file.");
  }

  foreach ($_POST['items'] as $path) {

    // generate filename to add to zip
    $filepath = 'downloads/' . $path . '.zip';

    if (file_exists($filepath)) {
      $zip->addFile($filepath, $path . '.zip') or die ("ERROR: Could not add the file $filename");
    } else {
      die("File $filepath doesnt exit");
    }
  }

  $zip->close();
}

Answer 2

the library itself gives you a code to see why it fails:

$ZIP_ERROR = [
  ZipArchive::ER_EXISTS => 'File already exists.',
  ZipArchive::ER_INCONS => 'Zip archive inconsistent.',
  ZipArchive::ER_INVAL => 'Invalid argument.',
  ZipArchive::ER_MEMORY => 'Malloc failure.',
  ZipArchive::ER_NOENT => 'No such file.',
  ZipArchive::ER_NOZIP => 'Not a zip archive.',
  ZipArchive::ER_OPEN => "Can't open file.",
  ZipArchive::ER_READ => 'Read error.',
  ZipArchive::ER_SEEK => 'Seek error.',
];

$result_code = $zip->open($zip_fullpath);
if( $result_code !== true ){
   $msg = isset($ZIP_ERROR[$result_code])? $ZIP_ERROR[$result_code] : 'Unknown error.';
   return ['error'=>$msg];
}

Answer 3

According to the documentation you cannot OR the open mode flags, you can only open in one mode. Check the file exists first and set the mode on open appropriately and see if that helps.

Answer 4

It also is possible that you are using php://output as filename (not for question author, but anyone who searching for this error), this is not supported by ZipArchive.

If you need to output zip file, then save it to temp file and use readfile function afterwards.