Why am I getting memory leaks in SimplePie when us

Question

I'm using SimplePie with PHP 5.3 (with gc enabled) to parse my RSS feeds. This works well and without problems when doing something like the following:

$simplePie = new SimplePie();
$simplePie->set_feed_url($rssURL);
$simplePie->enable_cache(false);
$simplePie->set_max_checked_feeds(10);
$simplePie->set_item_limit(0);
$simplePie->init();
$simplePie->handle_content_type();

foreach ($simplePie->get_items() as $key => $item) {
    $item->get_date("Y-m-d H:i:s");
    $item->get_id();
    $item->get_title();
    $item->get_content();
    $item->get_description();
    $item->get_category();
}

Memory debugging over 100 iterations (with different RSS feeds):

But when using $item->get_permalink(), my memory debugging looks like this over 100 iterations (with different RSS feeds).

Code to produce problem:

foreach ($simplePie->get_items() as $key => $item) {
    $item->get_date("Y-m-d H:i:s");
    $item->get_id();
    $item->get_title();
    $item->get_permalink(); //This creates a memory leak
    $item->get_content();
    $item->get_description();
    $item->get_category();
}

Things I've tried:

• Using get_link instead of get_permalink
• Using __destroy as mentioned here (even though it should be fixed for 5.3)

Current debugging process:

I seem to have traced the problem down to SimplePie_Item::get_permalink -> SimplePie_Item::get_link -> SimplePie_Item::get_links -> SimplePie_Item::sanitize -> SimplePie::sanitize -> SimplePie_Sanitize::sanitize -> SimplePie_Registry::call -> SimplePie_IRI::absolutize as of now.

What can I do to fix this?

Answer 1

This is actually not a memory leak, but rather static function caches that aren't being cleaned!

This is due to SimplePie_IRI::set_iri (and set_authority, and set_path). They set a static $cache variable, but they don't unset or clean this when a new instance of SimplePie is created, which means the variables only gets bigger and bigger.

This can be fixed by changing

public function set_authority($authority)
{
    static $cache;

    if (!$cache)
        $cache = array();

    /* etc */

to

public function set_authority($authority, $clear_cache = false)
{
    static $cache;
    if ($clear_cache) {
        $cache = null;
        return;
    }

    if (!$cache)
        $cache = array();

    /* etc */

..etc in the following functions:

• set_iri,
• set_authority,
• set_path,

And adding a destructor to SimplePie_IRI calling all the functions using a static cache, with a parameter of true in $clear_cache, will work:

/**
 * Clean up
 */
public function __destruct() {
    $this->set_iri(null, true);
    $this->set_path(null, true);
    $this->set_authority(null, true);
}

Which will now result in no gain in memory consumption over time:

Git Issue