PHP Iterators and Streams are awesome

Fabien Potencier

May 21, 2010

A lot of people complain about "problems" with PHP as a language (function name inconsistencies, register_globals, and much more).

But PHP also have a lot of awesome features; at least two of them are in my opinion largely underused: Iterators and Streams. You won't learn how to use them in this post, but with a simple example, I hope you will want to learn more about them.

Some weeks ago, I have rewritten the old sfFinder class for Symfony 2 using Iterators. It was a really great experience and it makes for a very extensible Finder Component.

The Finder class has been designed to be used to find files and directories locally on your machine. But there is more. What if I want to use the same interface for some Amazon S3 bucket? Is it possible? Of course it is, thanks to streams:

use Symfony\Components\Finder\Finder;

$s3 = new \Zend_Service_Amazon_S3($key, $secret);
$s3->registerStreamWrapper("s3");

$finder = new Finder();
$finder->name('photos*')->size('< 100K')->date('since 1 hour ago');
foreach ($finder->in('s3://bucket-name') as $file) {
    // do something

    print $file->getFilename()."\n";
}

Want to learn more? Read the documentation about Iterators and Streams on php.net.