Php create zip file (from post attachments wordpress)

Question

I am trying to create a zip file from email attachments in wordpress.

I tried using both methods below - but it gives nothing (no error messages, no file is created) - What am I doing wrong (again ..)

I don’t think that the fact that these messages are attachments to wordpress has anything to do with it - since these methods also do not work with regular files. why? → See answer.

$files_to_zip = array();// create files array
    //run a query
    $post_id = get_the_id();
    $args = array(
        'post_type' => 'attachment',
        'numberposts' => null,
        'post_status' => null,
        'post_parent' => $post_id
    );

    $attachments = get_posts($args);
    if ($attachments) {
foreach ($attachments as $attachment) {
        $files_to_zip [] = wp_get_attachment_url( $attachment->ID ); // populate files array
        }
    }
    print_r($files_to_zip);
    $zip = new ZipArchive;
    $zip->open('file.zip', ZipArchive::CREATE);
    foreach ($files_to_zip as $file) {
      $zip->addFile($file);
    }
    $zip->close();

as well as this method:

$files_to_zip = array(); // create array
//run a query
$post_id = get_the_id();
$args = array(
    'post_type' => 'attachment',
    'numberposts' => null,
    'post_status' => null,
    'post_parent' => $post_id
);
$zip = new ZipArchive;
$zip->open('file.zip', ZipArchive::CREATE);
$attachments = get_posts($args);
if ($attachments) {
    foreach ($attachments as $attachment) {
     $zip->addFile(wp_get_attachment_url( $attachment->ID ));
    }
}

print_r($files_to_zip);// debug - return file names OK

$zip->close();

Both methods did not return anything. Any ideas would be appreciated.

EDIT I - an example of an array print_r $ files_to_zip

print_r($files_to_zip);

Array ( 
[0] => http://localhost/testing_evn/wp-content/uploads/2012/03/wrt-62316IMAG0659.jpg 
[2] => http://localhost/testing_evn/wp-content/uploads/2012/03/wrt-85520_IGP0255.jpg
[3] => http://localhost/testing_evn/wp-content/uploads/2012/03/wrt-85520_IZTP0635.jpg
[4] => http://localhost/testing_evn/wp-content/uploads/2012/03/wrt-85520_ITG035t5.jpg
[5] => http://localhost/testing_evn/wp-content/uploads/2012/03/wrt-85520_IRTT7375.jpg )

.. get_attached_file() real ( - , , , php zip HTTP - ..)

Answer 1

- .

- PHP ZIP HTTP, PATH, URL...

, , Wordpress, get_attached_file() .

Array ( 
[0] => C:\Documents and Settings\OB\htdocs\test_env\wp-content\uploads\2012\03\wrt-62316IMAG0659.jpg 
[2] => C:\Documents and Settings\OB\htdocs\test_env\wp-content\uploads\2012\03\wrt-85520_IGP0255.jpg
[3] => C:\Documents and Settings\OB\htdocs\test_env\wp-content\uploads\2012\03\wrt-85520_IZTP0635.jpg
[4] => C:\Documents and Settings\OB\htdocs\test_env\wp-content\uploads\2012\03\wrt-85520_ITG035t5.jpg
[5] => C:\Documents and Settings\OB\htdocs\test_env\wp-content\uploads\2012\03\wrt-85520_IRTT7375.jpg )

( @DaveRandom var_dump - , - , .)

, gdlib - PHP, - HTTP. , , gdlib PDF, HTTP.