Php Stream to client while creating Tar file

Question

I have a special request for my PHP application.

Basically, an user can request a backup of his data as a TAR file. This archive contains a JSON file with the database informations (Profile, Various data, etc.) and a directory with all the files the user has upload since his registration.

So far, I've made the following code:

$phar = new PharData($output_filename);

$table_dump = self::dump_tables($customers);

$manifest = array();
$manifest['generation_time']  = time();
$manifest['manifest_version'] = self::DUMP_VERSION;

$phar->addFromString(self::MANIFEST_FILE, json_encode($manifest) );
$phar->addFromString(self::DATA_FILE, json_encode($table_dump) );

sql::select(file::sql_table, sql::true, file::sql_key);
$files_list = sql::fetch_all();
if ($files_list) foreach($files_list as $file_guid) {
  $file_path = file::forge_file_path($file_guid);
  if(is_file($file_path))
    $phar->addFile($file_path, basename($file_path));
}

return $output_filename;

It successfully returns a valid path with a valid TAR file that i can download. Today, the download is automatically started through a PHP Header but it takes ages to pack the TAR.

What I would like to know is: Is it possible to start downloading the file while it's being created ? (As a TAR file is made of collapsed files.)

Thanks for your help.

Answer 1

I think if PHP is writing the file you would need another thread to read from that file. PHP does not support multithreading. You could probably use exec() or an extension like phtreads.

I did not used it myself yet. But I read an article about it and it seems this could solve your problem.

Good luck.