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    <h3>Editing: Locator.php</h3>
    <textarea name="content" rows="20" cols="80">&lt;?php

/**
 * SimplePie
 *
 * A PHP-Based RSS and Atom Feed Framework.
 * Takes the hard work out of managing a complete RSS/Atom solution.
 *
 * Copyright (c) 2004-2022, Ryan Parman, Sam Sneddon, Ryan McCue, and contributors
 * All rights reserved.
 *
 * Redistribution and use in source and binary forms, with or without modification, are
 * permitted provided that the following conditions are met:
 *
 * 	* Redistributions of source code must retain the above copyright notice, this list of
 * 	  conditions and the following disclaimer.
 *
 * 	* Redistributions in binary form must reproduce the above copyright notice, this list
 * 	  of conditions and the following disclaimer in the documentation and/or other materials
 * 	  provided with the distribution.
 *
 * 	* Neither the name of the SimplePie Team nor the names of its contributors may be used
 * 	  to endorse or promote products derived from this software without specific prior
 * 	  written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS &quot;AS IS&quot; AND ANY EXPRESS
 * OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY
 * AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT HOLDERS
 * AND CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR
 * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR
 * SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR
 * OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 * @package SimplePie
 * @copyright 2004-2016 Ryan Parman, Sam Sneddon, Ryan McCue
 * @author Ryan Parman
 * @author Sam Sneddon
 * @author Ryan McCue
 * @link http://simplepie.org/ SimplePie
 * @license http://www.opensource.org/licenses/bsd-license.php BSD License
 */

namespace SimplePie;

/**
 * Used for feed auto-discovery
 *
 *
 * This class can be overloaded with {@see \SimplePie\SimplePie::set_locator_class()}
 *
 * @package SimplePie
 */
class Locator implements RegistryAware
{
    public $useragent;
    public $timeout;
    public $file;
    public $local = [];
    public $elsewhere = [];
    public $cached_entities = [];
    public $http_base;
    public $base;
    public $base_location = 0;
    public $checked_feeds = 0;
    public $max_checked_feeds = 10;
    public $force_fsockopen = false;
    public $curl_options = [];
    public $dom;
    protected $registry;

    public function __construct(\SimplePie\File $file, $timeout = 10, $useragent = null, $max_checked_feeds = 10, $force_fsockopen = false, $curl_options = [])
    {
        $this-&gt;file = $file;
        $this-&gt;useragent = $useragent;
        $this-&gt;timeout = $timeout;
        $this-&gt;max_checked_feeds = $max_checked_feeds;
        $this-&gt;force_fsockopen = $force_fsockopen;
        $this-&gt;curl_options = $curl_options;

        if (class_exists('DOMDocument') &amp;&amp; $this-&gt;file-&gt;body != '') {
            $this-&gt;dom = new \DOMDocument();

            set_error_handler(['SimplePie\Misc', 'silence_errors']);
            try {
                $this-&gt;dom-&gt;loadHTML($this-&gt;file-&gt;body);
            } catch (\Throwable $ex) {
                $this-&gt;dom = null;
            }
            restore_error_handler();
        } else {
            $this-&gt;dom = null;
        }
    }

    public function set_registry(\SimplePie\Registry $registry)/* : void */
    {
        $this-&gt;registry = $registry;
    }

    public function find($type = \SimplePie\SimplePie::LOCATOR_ALL, &amp;$working = null)
    {
        if ($this-&gt;is_feed($this-&gt;file)) {
            return $this-&gt;file;
        }

        if ($this-&gt;file-&gt;method &amp; \SimplePie\SimplePie::FILE_SOURCE_REMOTE) {
            $sniffer = $this-&gt;registry-&gt;create(Content\Type\Sniffer::class, [$this-&gt;file]);
            if ($sniffer-&gt;get_type() !== 'text/html') {
                return null;
            }
        }

        if ($type &amp; ~\SimplePie\SimplePie::LOCATOR_NONE) {
            $this-&gt;get_base();
        }

        if ($type &amp; \SimplePie\SimplePie::LOCATOR_AUTODISCOVERY &amp;&amp; $working = $this-&gt;autodiscovery()) {
            return $working[0];
        }

        if ($type &amp; (\SimplePie\SimplePie::LOCATOR_LOCAL_EXTENSION | \SimplePie\SimplePie::LOCATOR_LOCAL_BODY | \SimplePie\SimplePie::LOCATOR_REMOTE_EXTENSION | \SimplePie\SimplePie::LOCATOR_REMOTE_BODY) &amp;&amp; $this-&gt;get_links()) {
            if ($type &amp; \SimplePie\SimplePie::LOCATOR_LOCAL_EXTENSION &amp;&amp; $working = $this-&gt;extension($this-&gt;local)) {
                return $working[0];
            }

            if ($type &amp; \SimplePie\SimplePie::LOCATOR_LOCAL_BODY &amp;&amp; $working = $this-&gt;body($this-&gt;local)) {
                return $working[0];
            }

            if ($type &amp; \SimplePie\SimplePie::LOCATOR_REMOTE_EXTENSION &amp;&amp; $working = $this-&gt;extension($this-&gt;elsewhere)) {
                return $working[0];
            }

            if ($type &amp; \SimplePie\SimplePie::LOCATOR_REMOTE_BODY &amp;&amp; $working = $this-&gt;body($this-&gt;elsewhere)) {
                return $working[0];
            }
        }
        return null;
    }

    public function is_feed($file, $check_html = false)
    {
        if ($file-&gt;method &amp; \SimplePie\SimplePie::FILE_SOURCE_REMOTE) {
            $sniffer = $this-&gt;registry-&gt;create(Content\Type\Sniffer::class, [$file]);
            $sniffed = $sniffer-&gt;get_type();
            $mime_types = ['application/rss+xml', 'application/rdf+xml',
                                'text/rdf', 'application/atom+xml', 'text/xml',
                                'application/xml', 'application/x-rss+xml'];
            if ($check_html) {
                $mime_types[] = 'text/html';
            }

            return in_array($sniffed, $mime_types);
        } elseif ($file-&gt;method &amp; \SimplePie\SimplePie::FILE_SOURCE_LOCAL) {
            return true;
        } else {
            return false;
        }
    }

    public function get_base()
    {
        if ($this-&gt;dom === null) {
            throw new \SimplePie\Exception('DOMDocument not found, unable to use locator');
        }
        $this-&gt;http_base = $this-&gt;file-&gt;url;
        $this-&gt;base = $this-&gt;http_base;
        $elements = $this-&gt;dom-&gt;getElementsByTagName('base');
        foreach ($elements as $element) {
            if ($element-&gt;hasAttribute('href')) {
                $base = $this-&gt;registry-&gt;call(Misc::class, 'absolutize_url', [trim($element-&gt;getAttribute('href')), $this-&gt;http_base]);
                if ($base === false) {
                    continue;
                }
                $this-&gt;base = $base;
                $this-&gt;base_location = method_exists($element, 'getLineNo') ? $element-&gt;getLineNo() : 0;
                break;
            }
        }
    }

    public function autodiscovery()
    {
        $done = [];
        $feeds = [];
        $feeds = array_merge($feeds, $this-&gt;search_elements_by_tag('link', $done, $feeds));
        $feeds = array_merge($feeds, $this-&gt;search_elements_by_tag('a', $done, $feeds));
        $feeds = array_merge($feeds, $this-&gt;search_elements_by_tag('area', $done, $feeds));

        if (!empty($feeds)) {
            return array_values($feeds);
        }

        return null;
    }

    protected function search_elements_by_tag($name, &amp;$done, $feeds)
    {
        if ($this-&gt;dom === null) {
            throw new \SimplePie\Exception('DOMDocument not found, unable to use locator');
        }

        $links = $this-&gt;dom-&gt;getElementsByTagName($name);
        foreach ($links as $link) {
            if ($this-&gt;checked_feeds === $this-&gt;max_checked_feeds) {
                break;
            }
            if ($link-&gt;hasAttribute('href') &amp;&amp; $link-&gt;hasAttribute('rel')) {
                $rel = array_unique($this-&gt;registry-&gt;call(Misc::class, 'space_separated_tokens', [strtolower($link-&gt;getAttribute('rel'))]));
                $line = method_exists($link, 'getLineNo') ? $link-&gt;getLineNo() : 1;

                if ($this-&gt;base_location &lt; $line) {
                    $href = $this-&gt;registry-&gt;call(Misc::class, 'absolutize_url', [trim($link-&gt;getAttribute('href')), $this-&gt;base]);
                } else {
                    $href = $this-&gt;registry-&gt;call(Misc::class, 'absolutize_url', [trim($link-&gt;getAttribute('href')), $this-&gt;http_base]);
                }
                if ($href === false) {
                    continue;
                }

                if (!in_array($href, $done) &amp;&amp; in_array('feed', $rel) || (in_array('alternate', $rel) &amp;&amp; !in_array('stylesheet', $rel) &amp;&amp; $link-&gt;hasAttribute('type') &amp;&amp; in_array(strtolower($this-&gt;registry-&gt;call(Misc::class, 'parse_mime', [$link-&gt;getAttribute('type')])), ['text/html', 'application/rss+xml', 'application/atom+xml'])) &amp;&amp; !isset($feeds[$href])) {
                    $this-&gt;checked_feeds++;
                    $headers = [
                        'Accept' =&gt; 'application/atom+xml, application/rss+xml, application/rdf+xml;q=0.9, application/xml;q=0.8, text/xml;q=0.8, text/html;q=0.7, unknown/unknown;q=0.1, application/unknown;q=0.1, */*;q=0.1',
                    ];
                    $feed = $this-&gt;registry-&gt;create(File::class, [$href, $this-&gt;timeout, 5, $headers, $this-&gt;useragent, $this-&gt;force_fsockopen, $this-&gt;curl_options]);
                    if ($feed-&gt;success &amp;&amp; ($feed-&gt;method &amp; \SimplePie\SimplePie::FILE_SOURCE_REMOTE === 0 || ($feed-&gt;status_code === 200 || $feed-&gt;status_code &gt; 206 &amp;&amp; $feed-&gt;status_code &lt; 300)) &amp;&amp; $this-&gt;is_feed($feed, true)) {
                        $feeds[$href] = $feed;
                    }
                }
                $done[] = $href;
            }
        }

        return $feeds;
    }

    public function get_links()
    {
        if ($this-&gt;dom === null) {
            throw new \SimplePie\Exception('DOMDocument not found, unable to use locator');
        }

        $links = $this-&gt;dom-&gt;getElementsByTagName('a');
        foreach ($links as $link) {
            if ($link-&gt;hasAttribute('href')) {
                $href = trim($link-&gt;getAttribute('href'));
                $parsed = $this-&gt;registry-&gt;call(Misc::class, 'parse_url', [$href]);
                if ($parsed['scheme'] === '' || preg_match('/^(https?|feed)?$/i', $parsed['scheme'])) {
                    if (method_exists($link, 'getLineNo') &amp;&amp; $this-&gt;base_location &lt; $link-&gt;getLineNo()) {
                        $href = $this-&gt;registry-&gt;call(Misc::class, 'absolutize_url', [trim($link-&gt;getAttribute('href')), $this-&gt;base]);
                    } else {
                        $href = $this-&gt;registry-&gt;call(Misc::class, 'absolutize_url', [trim($link-&gt;getAttribute('href')), $this-&gt;http_base]);
                    }
                    if ($href === false) {
                        continue;
                    }

                    $current = $this-&gt;registry-&gt;call(Misc::class, 'parse_url', [$this-&gt;file-&gt;url]);

                    if ($parsed['authority'] === '' || $parsed['authority'] === $current['authority']) {
                        $this-&gt;local[] = $href;
                    } else {
                        $this-&gt;elsewhere[] = $href;
                    }
                }
            }
        }
        $this-&gt;local = array_unique($this-&gt;local);
        $this-&gt;elsewhere = array_unique($this-&gt;elsewhere);
        if (!empty($this-&gt;local) || !empty($this-&gt;elsewhere)) {
            return true;
        }
        return null;
    }

    public function get_rel_link($rel)
    {
        if ($this-&gt;dom === null) {
            throw new \SimplePie\Exception('DOMDocument not found, unable to use '.
                                          'locator');
        }
        if (!class_exists('DOMXpath')) {
            throw new \SimplePie\Exception('DOMXpath not found, unable to use '.
                                          'get_rel_link');
        }

        $xpath = new \DOMXpath($this-&gt;dom);
        $query = '//a[@rel and @href] | //link[@rel and @href]';
        foreach ($xpath-&gt;query($query) as $link) {
            $href = trim($link-&gt;getAttribute('href'));
            $parsed = $this-&gt;registry-&gt;call(Misc::class, 'parse_url', [$href]);
            if ($parsed['scheme'] === '' ||
                preg_match('/^https?$/i', $parsed['scheme'])) {
                if (method_exists($link, 'getLineNo') &amp;&amp;
                    $this-&gt;base_location &lt; $link-&gt;getLineNo()) {
                    $href = $this-&gt;registry-&gt;call(
                        Misc::class,
                        'absolutize_url',
                        [trim($link-&gt;getAttribute('href')), $this-&gt;base]
                    );
                } else {
                    $href = $this-&gt;registry-&gt;call(
                        Misc::class,
                        'absolutize_url',
                        [trim($link-&gt;getAttribute('href')), $this-&gt;http_base]
                    );
                }
                if ($href === false) {
                    return null;
                }
                $rel_values = explode(' ', strtolower($link-&gt;getAttribute('rel')));
                if (in_array($rel, $rel_values)) {
                    return $href;
                }
            }
        }
        return null;
    }

    public function extension(&amp;$array)
    {
        foreach ($array as $key =&gt; $value) {
            if ($this-&gt;checked_feeds === $this-&gt;max_checked_feeds) {
                break;
            }
            if (in_array(strtolower(strrchr($value, '.')), ['.rss', '.rdf', '.atom', '.xml'])) {
                $this-&gt;checked_feeds++;

                $headers = [
                    'Accept' =&gt; 'application/atom+xml, application/rss+xml, application/rdf+xml;q=0.9, application/xml;q=0.8, text/xml;q=0.8, text/html;q=0.7, unknown/unknown;q=0.1, application/unknown;q=0.1, */*;q=0.1',
                ];
                $feed = $this-&gt;registry-&gt;create(File::class, [$value, $this-&gt;timeout, 5, $headers, $this-&gt;useragent, $this-&gt;force_fsockopen, $this-&gt;curl_options]);
                if ($feed-&gt;success &amp;&amp; ($feed-&gt;method &amp; \SimplePie\SimplePie::FILE_SOURCE_REMOTE === 0 || ($feed-&gt;status_code === 200 || $feed-&gt;status_code &gt; 206 &amp;&amp; $feed-&gt;status_code &lt; 300)) &amp;&amp; $this-&gt;is_feed($feed)) {
                    return [$feed];
                } else {
                    unset($array[$key]);
                }
            }
        }
        return null;
    }

    public function body(&amp;$array)
    {
        foreach ($array as $key =&gt; $value) {
            if ($this-&gt;checked_feeds === $this-&gt;max_checked_feeds) {
                break;
            }
            if (preg_match('/(feed|rss|rdf|atom|xml)/i', $value)) {
                $this-&gt;checked_feeds++;
                $headers = [
                    'Accept' =&gt; 'application/atom+xml, application/rss+xml, application/rdf+xml;q=0.9, application/xml;q=0.8, text/xml;q=0.8, text/html;q=0.7, unknown/unknown;q=0.1, application/unknown;q=0.1, */*;q=0.1',
                ];
                $feed = $this-&gt;registry-&gt;create(File::class, [$value, $this-&gt;timeout, 5, null, $this-&gt;useragent, $this-&gt;force_fsockopen, $this-&gt;curl_options]);
                if ($feed-&gt;success &amp;&amp; ($feed-&gt;method &amp; \SimplePie\SimplePie::FILE_SOURCE_REMOTE === 0 || ($feed-&gt;status_code === 200 || $feed-&gt;status_code &gt; 206 &amp;&amp; $feed-&gt;status_code &lt; 300)) &amp;&amp; $this-&gt;is_feed($feed)) {
                    return [$feed];
                } else {
                    unset($array[$key]);
                }
            }
        }
        return null;
    }
}

class_alias('SimplePie\Locator', 'SimplePie_Locator', false);
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