mirror of
https://code.mensbeam.com/MensBeam/Arsse.git
synced 2024-12-22 13:12:41 +00:00
437 lines
20 KiB
PHP
437 lines
20 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
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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
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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::$conf->fetchUserAgentString ?? sprintf(
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'Arsse/%s (%s %s; %s; https://thearsse.com/)',
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Arsse::VERSION, // Arsse version
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php_uname('s'), // OS
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php_uname('r'), // OS version
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php_uname('m') // platform architecture
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);
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$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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} catch (\GuzzleHttp\Exception\GuzzleException $e) {
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throw new Feed\Exception($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
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libxml_use_internal_errors(false);
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} catch (PicoFeedException $e) {
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// work around a PicoFeed memory leak
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libxml_use_internal_errors(false);
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throw new Feed\Exception($this->resource->getUrl(), $e);
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} catch (\GuzzleHttp\Exception\GuzzleException $e) {
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// work around a PicoFeed memory leak
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libxml_use_internal_errors(false);
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throw new Feed\Exception($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 (!$this->modified) {
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if ($this->lastModified) {
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$diff = $now->getTimestamp() - $this->lastModified->getTimestamp();
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$offset = $this->normalizeDateDiff($diff);
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} else {
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// if no timestamp is available, fall back to three hours
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$offset = "3 hours";
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}
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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 $offset;
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}
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protected function computeLastModified(): ?\DateTimeImmutable {
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if (!$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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