mirror of
https://code.mensbeam.com/MensBeam/Arsse.git
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89bfc23d32
Also move date formats to the ValueInfo class Standardizing on immutables avoids any possible ambiguity in the API of the resultant value, as well as any ambiguity as to whether a DateTime output instance is the same instance or a clone (they had been clones)
426 lines
19 KiB
PHP
426 lines
19 KiB
PHP
<?php
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/** @license MIT
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* Copyright 2017 J. King, Dustin Wilson et al.
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* See LICENSE and AUTHORS files for details */
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declare(strict_types=1);
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namespace JKingWeb\Arsse;
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use JKingWeb\Arsse\Misc\Date;
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use PicoFeed\PicoFeedException;
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use PicoFeed\Config\Config;
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use PicoFeed\Client\Client;
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use PicoFeed\Reader\Reader;
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use PicoFeed\Reader\Favicon;
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use PicoFeed\Scraper\Scraper;
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class Feed {
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public $data = null;
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public $favicon;
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public $resource;
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public $modified = false;
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public $lastModified;
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public $nextFetch;
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public $newItems = [];
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public $changedItems = [];
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public static function discover(string $url, string $username = '', string $password = ''): string {
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// fetch the candidate feed
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$f = self::download($url, "", "", $username, $password);
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if ($f->reader->detectFormat($f->getContent())) {
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// if the prospective URL is a feed, use it
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$out = $url;
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} else {
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$links = $f->reader->find($f->getUrl(), $f->getContent());
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if (!$links) {
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// work around a PicoFeed memory leak FIXME: remove this hack (or not) once PicoFeed stops leaking memory
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libxml_use_internal_errors(false);
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throw new Feed\Exception($url, new \PicoFeed\Reader\SubscriptionNotFoundException('Unable to find a subscription'));
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} else {
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$out = $links[0];
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}
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}
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// work around a PicoFeed memory leak FIXME: remove this hack (or not) once PicoFeed stops leaking memory
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libxml_use_internal_errors(false);
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return $out;
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}
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public function __construct(int $feedID = null, string $url, string $lastModified = '', string $etag = '', string $username = '', string $password = '', bool $scrape = false) {
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// fetch the feed
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$this->resource = self::download($url, $lastModified, $etag, $username, $password);
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// format the HTTP Last-Modified date returned
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$lastMod = $this->resource->getLastModified();
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if (strlen($lastMod)) {
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$this->lastModified = Date::normalize($lastMod, "http");
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}
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$this->modified = $this->resource->isModified();
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//parse the feed, if it has been modified
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if ($this->modified) {
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$this->parse();
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// ascertain whether there are any articles not in the database
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$this->matchToDatabase($feedID);
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// if caching header fields are not sent by the server, try to ascertain a last-modified date from the feed contents
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if (!$this->lastModified) {
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$this->lastModified = $this->computeLastModified();
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}
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// we only really care if articles have been modified; if there are no new articles, act as if the feed is unchanged
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if (!sizeof($this->newItems) && !sizeof($this->changedItems)) {
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$this->modified = false;
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}
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// if requested, scrape full content for any new and changed items
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if ($scrape) {
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$this->scrape();
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}
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}
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// compute the time at which the feed should next be fetched
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$this->nextFetch = $this->computeNextFetch();
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}
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protected static function configure(): Config {
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$userAgent = Arsse::$conf->fetchUserAgentString ?? sprintf(
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'Arsse/%s (%s %s; %s; https://thearsse.com/) PicoFeed (https://github.com/miniflux/picoFeed)',
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Arsse::VERSION, // Arsse version
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php_uname('s'), // OS
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php_uname('r'), // OS version
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php_uname('m') // platform architecture
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);
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$config = new Config;
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$config->setMaxBodySize(Arsse::$conf->fetchSizeLimit);
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$config->setClientTimeout(Arsse::$conf->fetchTimeout);
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$config->setGrabberTimeout(Arsse::$conf->fetchTimeout);
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$config->setClientUserAgent($userAgent);
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$config->setGrabberUserAgent($userAgent);
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return $config;
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}
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protected static function download(string $url, string $lastModified, string $etag, string $username, string $password): Client {
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try {
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$reader = new Reader(self::configure());
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$client = $reader->download($url, $lastModified, $etag, $username, $password);
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$client->reader = $reader;
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return $client;
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} catch (PicoFeedException $e) {
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throw new Feed\Exception($url, $e);
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}
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}
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protected function parse(): bool {
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try {
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$feed = $this->resource->reader->getParser(
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$this->resource->getUrl(),
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$this->resource->getContent(),
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$this->resource->getEncoding()
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)->execute();
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// Grab the favicon for the feed; returns an empty string if it cannot find one.
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// Some feeds might use a different domain (eg: feedburner), so the site url is
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// used instead of the feed's url.
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$this->favicon = (new Favicon)->find($feed->siteUrl);
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// work around a PicoFeed memory leak FIXME: remove this hack (or not) once PicoFeed stops leaking memory
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libxml_use_internal_errors(false);
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} catch (PicoFeedException $e) {
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// work around a PicoFeed memory leak FIXME: remove this hack (or not) once PicoFeed stops leaking memory
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libxml_use_internal_errors(false);
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throw new Feed\Exception($this->resource->getUrl(), $e);
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}
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// PicoFeed does not provide valid ids when there is no id element. Its solution
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// of hashing the url, title, and content together for the id if there is no id
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// element is stupid. Many feeds are frankenstein mixtures of Atom and RSS, but
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// some are pure RSS with guid elements while others use the Dublin Core spec for
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// identification. These feeds shouldn't be duplicated when updated. That should
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// only be reserved for severely broken feeds.
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foreach ($feed->items as $f) {
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// Hashes used for comparison to check for updates and also to identify when an
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// id doesn't exist.
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$content = $f->content.$f->enclosureUrl.$f->enclosureType;
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// if the item link URL and item title are both equal to the feed link URL, then the item has neither a link URL nor a title
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if ($f->url==$feed->siteUrl && $f->title==$feed->siteUrl) {
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$f->urlTitleHash = "";
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} else {
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$f->urlTitleHash = hash('sha256', $f->url.$f->title);
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}
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// if the item link URL is equal to the feed link URL, it has no link URL; if there is additionally no content, these should not be hashed
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if (!strlen($content) && $f->url==$feed->siteUrl) {
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$f->urlContentHash = "";
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} else {
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$f->urlContentHash = hash('sha256', $f->url.$content);
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}
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// if the item's title is the same as its link URL, it has no title; if there is additionally no content, these should not be hashed
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if (!strlen($content) && $f->title==$f->url) {
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$f->titleContentHash = "";
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} else {
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$f->titleContentHash = hash('sha256', $f->title.$content);
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}
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$f->id = null;
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// prefer an Atom ID as the item's ID
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$id = (string) $f->xml->children('http://www.w3.org/2005/Atom')->id;
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// otherwise use the RSS2 guid element
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if (!strlen($id)) {
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$id = (string) $f->xml->guid;
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}
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// otherwise use the Dublin Core identifier element
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if (!strlen($id)) {
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$id = (string) $f->xml->children('http://purl.org/dc/elements/1.1/')->identifier;
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}
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// otherwise there is no ID; if there is one, hash it
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if (strlen($id)) {
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$f->id = hash('sha256', $id);
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}
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// PicoFeed also doesn't gather up categories, so we do this as well
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$f->categories = [];
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// first add Atom categories
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foreach ($f->xml->children('http://www.w3.org/2005/Atom')->category as $c) {
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// if the category has a label, use that
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$name = (string) $c->attributes()->label;
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// otherwise use the term
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if (!strlen($name)) {
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$name = (string) $c->attributes()->term;
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}
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// ... assuming it has that much
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if (strlen($name)) {
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$f->categories[] = $name;
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}
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}
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// next add RSS2 categories
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foreach ($f->xml->children()->category as $c) {
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$name = (string) $c;
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if (strlen($name)) {
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$f->categories[] = $name;
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}
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}
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// and finally try Dublin Core subjects
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foreach ($f->xml->children('http://purl.org/dc/elements/1.1/')->subject as $c) {
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$name = (string) $c;
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if (strlen($name)) {
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$f->categories[] = $name;
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}
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}
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//sort the results
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sort($f->categories);
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}
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$this->data = $feed;
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return true;
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}
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protected function deduplicateItems(array $items): array {
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/* Rationale:
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Some newsfeeds (notably Planet) include multiple versions of an
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item if it is updated. As we only care about the latest, we
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try to remove any "old" versions of an item that might also be
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present within the feed.
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*/
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$out = [];
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foreach ($items as $item) {
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foreach ($out as $index => $check) {
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// if the two items both have IDs and they differ, they do not match, regardless of hashes
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if ($item->id && $check->id && $item->id != $check->id) {
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continue;
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}
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// if the two items have the same ID or any one hash matches, they are two versions of the same item
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if (
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($item->id && $check->id && $item->id == $check->id) ||
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($item->urlTitleHash && $item->urlTitleHash == $check->urlTitleHash) ||
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($item->urlContentHash && $item->urlContentHash == $check->urlContentHash) ||
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($item->titleContentHash && $item->titleContentHash == $check->titleContentHash)
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) {
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if (// because newsfeeds are usually order newest-first, the later item should only be used if...
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// the later item has an update date and the existing item does not
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($item->updatedDate && !$check->updatedDate) ||
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// the later item has an update date newer than the existing item's
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($item->updatedDate && $check->updatedDate && $item->updatedDate->getTimestamp() > $check->updatedDate->getTimestamp()) ||
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// neither item has update dates, both have publish dates, and the later item has a newer publish date
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(!$item->updatedDate && !$check->updatedDate && $item->publishedDate && $check->publishedDate && $item->publishedDate->getTimestamp() > $check->publishedDate->getTimestamp())
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) {
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// if the later item should be used, replace the existing one
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$out[$index] = $item;
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continue 2;
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} else {
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// otherwise skip the item
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continue 2;
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}
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}
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}
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// if there was no match, add the item
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$out[] = $item;
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}
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return $out;
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}
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protected function matchToDatabase(int $feedID = null): bool {
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// first perform deduplication on items
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$items = $this->deduplicateItems($this->data->items);
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// if we haven't been given a database feed ID to check against, all items are new
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if (is_null($feedID)) {
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$this->newItems = $items;
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return true;
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}
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// get as many of the latest articles in the database as there are in the feed
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$articles = Arsse::$db->feedMatchLatest($feedID, sizeof($items))->getAll();
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// perform a first pass matching the latest articles against items in the feed
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list($this->newItems, $this->changedItems) = $this->matchItems($items, $articles);
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if (sizeof($this->newItems) && sizeof($items) <= sizeof($articles)) {
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// if we need to, perform a second pass on the database looking specifically for IDs and hashes of the new items
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$ids = $hashesUT = $hashesUC = $hashesTC = [];
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foreach ($this->newItems as $i) {
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if ($i->id) {
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$ids[] = $i->id;
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}
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if ($i->urlTitleHash) {
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$hashesUT[] = $i->urlTitleHash;
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}
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if ($i->urlContentHash) {
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$hashesUC[] = $i->urlContentHash;
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}
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if ($i->titleContentHash) {
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$hashesTC[] = $i->titleContentHash;
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}
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}
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$articles = Arsse::$db->feedMatchIds($feedID, $ids, $hashesUT, $hashesUC, $hashesTC)->getAll();
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list($this->newItems, $changed) = $this->matchItems($this->newItems, $articles);
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// merge the two change-lists, preserving keys
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$this->changedItems = array_combine(array_merge(array_keys($this->changedItems), array_keys($changed)), array_merge($this->changedItems, $changed));
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}
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return true;
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}
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protected function matchItems(array $items, array $articles): array {
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$new = $edited = [];
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// iterate through the articles and for each determine whether it is existing, edited, or entirely new
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foreach ($items as $i) {
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$found = false;
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foreach ($articles as $a) {
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// if the item has an ID and it doesn't match the article ID, the two don't match, regardless of hashes
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if ($i->id && $i->id !== $a['guid']) {
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continue;
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}
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if (
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// the item matches if the GUID matches...
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($i->id && $i->id === $a['guid']) ||
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// ... or if any one of the hashes match
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($i->urlTitleHash && $i->urlTitleHash === $a['url_title_hash']) ||
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($i->urlContentHash && $i->urlContentHash === $a['url_content_hash']) ||
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($i->titleContentHash && $i->titleContentHash === $a['title_content_hash'])
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) {
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if ($i->updatedDate && Date::transform($i->updatedDate, "sql") !== $a['edited']) {
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// if the item has an edit timestamp and it doesn't match that of the article in the database, the the article has been edited
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// we store the item index and database record ID as a key/value pair
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$found = true;
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$edited[$a['id']] = $i;
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break;
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} elseif ($i->urlTitleHash !== $a['url_title_hash'] || $i->urlContentHash !== $a['url_content_hash'] || $i->titleContentHash !== $a['title_content_hash']) {
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// if any of the hashes do not match, then the article has been edited
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$found = true;
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$edited[$a['id']] = $i;
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break;
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} else {
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// otherwise the item is unchanged and we can ignore it
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$found = true;
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break;
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}
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}
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}
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if (!$found) {
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$new[] = $i;
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}
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}
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return [$new, $edited];
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}
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protected function computeNextFetch(): \DateTimeImmutable {
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$now = Date::normalize(time());
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if (!$this->modified) {
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$diff = $now->getTimestamp() - $this->lastModified->getTimestamp();
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$offset = $this->normalizeDateDiff($diff);
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return $now->modify("+".$offset);
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} else {
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// the algorithm for updated feeds (returning 200 rather than 304) uses the same parameters as for 304,
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// save that the last three intervals between item dates are computed, and if any two fall within
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// the same interval range, that interval is used (e.g. if the intervals are 23m, 12m, and 4h, the used
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// interval is "less than 30m"). If there is no commonality, the feed is checked in 1 hour.
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$offsets = [];
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$dates = $this->gatherDates();
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if (sizeof($dates) > 3) {
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for ($a = 0; $a < 3; $a++) {
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$diff = $dates[$a] - $dates[$a+1];
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$offsets[] = $this->normalizeDateDiff($diff);
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}
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if ($offsets[0]==$offsets[1] || $offsets[0]==$offsets[2]) {
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return $now->modify("+".$offsets[0]);
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} elseif ($offsets[1]==$offsets[2]) {
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return $now->modify("+".$offsets[1]);
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} else {
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return $now->modify("+ 1 hour");
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}
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} else {
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return $now->modify("+ 1 hour");
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}
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}
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}
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public static function nextFetchOnError($errCount): \DateTimeImmutable {
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if ($errCount < 3) {
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$offset = "5 minutes";
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} elseif ($errCount < 15) {
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$offset = "3 hours";
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} else {
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$offset = "1 day";
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}
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return Date::normalize("now + ".$offset);
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}
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protected function normalizeDateDiff(int $diff): string {
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if ($diff < (30 * 60)) { // less than 30 minutes
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$offset = "15 minutes";
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} elseif ($diff < (60 * 60)) { // less than an hour
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$offset = "30 minutes";
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} elseif ($diff < (3 * 60 * 60)) { // less than three hours
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$offset = "1 hour";
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} elseif ($diff >= (36 * 60 * 60)) { // more than 36 hours
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$offset = "1 day";
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} else {
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$offset = "3 hours";
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}
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return $offset;
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}
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protected function computeLastModified() {
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if (!$this->modified) {
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return $this->lastModified; // @codeCoverageIgnore
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}
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$dates = $this->gatherDates();
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if (sizeof($dates)) {
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return Date::normalize($dates[0]);
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} else {
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return null; // @codeCoverageIgnore
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}
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}
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protected function gatherDates(): array {
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$dates = [];
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foreach ($this->data->items as $item) {
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if ($item->updatedDate) {
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$dates[] = $item->updatedDate->getTimestamp();
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}
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if ($item->publishedDate) {
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$dates[] = $item->publishedDate->getTimestamp();
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}
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}
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$dates = array_unique($dates, \SORT_NUMERIC);
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rsort($dates);
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return $dates;
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}
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protected function scrape(): bool {
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$scraper = new Scraper(self::configure());
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foreach (array_merge($this->newItems, $this->changedItems) as $item) {
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$scraper->setUrl($item->url);
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$scraper->execute();
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if ($scraper->hasRelevantContent()) {
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$item->content = $scraper->getFilteredContent();
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}
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}
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return true;
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}
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}
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