Parsing RSS/Atom Feeds with PHP

When parsing RSS or Atom feeds using Magpie RSS, it's important to consider alternative options that can handle well-formed feeds. One such option is SimpleXML.

SimpleXML, built into PHP, offers a user-friendly structure for parsing XML documents. It detects XML errors and warns upon encountering any issues. To address such errors, you can consider using HTML Tidy to clean up the source.

Here's a basic class that utilizes SimpleXML to parse RSS feeds:

class BlogPost {
    public $date;
    public $ts;
    public $link;
    public $title;
    public $text;
}

class BlogFeed {
    public $posts = [];

    public function __construct($file_or_url) {
        $file_or_url = $this->resolveFile($file_or_url);
        if (!$x = simplexml_load_file($file_or_url)) return;

        foreach ($x->channel->item as $item) {
            $post = new BlogPost();
            $post->date = (string)$item->pubDate;
            $post->ts = strtotime($item->pubDate);
            $post->link = (string)$item->link;
            $post->title = (string)$item->title;
            $post->text = (string)$item->description;
            $post->summary = $this->summarizeText($post->text);

            $this->posts[] = $post;
        }
    }

    private function resolveFile($file_or_url) {
        if (!preg_match('|^https?:|', $file_or_url))
            $feed_uri = $_SERVER['DOCUMENT_ROOT'] .'/shared/xml/'. $file_or_url;
        else
            $feed_uri = $file_or_url;

        return $feed_uri;
    }

    private function summarizeText($summary) {
        $summary = strip_tags($summary);
        $max_len = 100;
        if (strlen($summary) > $max_len)
            $summary = substr($summary, 0, $max_len) . '...';

        return $summary;
    }
}

By utilizing SimpleXML and handling XML errors, you can effectively parse both RSS and Atom feeds using PHP.