rss-bridge/bridges/YouTubeCommunityTabBridge.php

<?php
class YouTubeCommunityTabBridge extends BridgeAbstract {
	const NAME = 'YouTube Community Tab Bridge';
	const URI = 'https://www.youtube.com';
	const DESCRIPTION = 'Returns posts from a channel\'s community tab';
	const MAINTAINER = 'VerifiedJoseph';
	const PARAMETERS = array(
		'By channel ID' => array(
			'channel' => array(
				'name' => 'Channel ID',
				'type' => 'text',
				'required' => true,
				'exampleValue' => 'UCULkRHBdLC5ZcEQBaL0oYHQ'
			)
		),
		'By username' => array(
			'username' => array(
				'name' => 'Username',
				'type' => 'text',
				'required' => true,
				'exampleValue' => 'YouTubeUK'
			),
		)
	);

	const CACHE_TIMEOUT = 3600; // 1 hour

	private $feedUrl = '';
	private $feedName = '';
	private $itemTitle = '';

	private $urlRegex = '/youtube\.com\/(channel|user|c)\/([\w]+)\/community/';
	private $jsonRegex = '/var ytInitialData = (.*);<\/script><link rel="canonical"/';

	public function detectParameters($url) {
		$params = array();

		if(preg_match($this->urlRegex, $url, $matches)) {
			if ($matches[1] === 'channel') {
				$params['context'] = 'By channel ID';
				$params['channel'] = $matches[2];
			}

			if ($matches[1] === 'user') {
				$params['context'] = 'By username';
				$params['username'] = $matches[2];
			}

			return $params;
		}

		return null;
	}

	public function collectData() {

		if (is_null($this->getInput('username')) === false) {
			try {
				$this->feedUrl = $this->buildCommunityUri($this->getInput('username'), 'c');
				$html = getSimpleHTMLDOM($this->feedUrl);

			} catch (Exception $e) {
				$this->feedUrl = $this->buildCommunityUri($this->getInput('username'), 'user');
				$html = getSimpleHTMLDOM($this->feedUrl);
			}
		} else {
			$this->feedUrl = $this->buildCommunityUri($this->getInput('channel'), 'channel');
			$html = getSimpleHTMLDOM($this->feedUrl);
		}

		$json = $this->extractJson($html->find('body', 0)->innertext);

		$this->feedName = $json->header->c4TabbedHeaderRenderer->title;

		if ($this->hasCommunityTab($json) === false) {
			returnServerError('Channel does not have a community tab');
		}

		foreach ($this->getCommunityPosts($json) as $post) {
			$this->itemTitle = '';

			if (!isset($post->backstagePostThreadRenderer)) {
				continue;
			}

			$details = $post->backstagePostThreadRenderer->post->backstagePostRenderer;

			$item = array();
			$item['uri'] = self::URI . '/post/' . $details->postId;
			$item['author'] = $details->authorText->runs[0]->text;
			$item['content'] = '';

			if (isset($details->contentText)) {
				$text = $this->getText($details->contentText->runs);

				$this->itemTitle = $this->ellipsisTitle($text);
				$item['content'] = $text;
			}

			$item['content'] .= $this->getAttachments($details);
			$item['title'] = $this->itemTitle;

			$this->items[] = $item;
		}
	}

	public function getURI() {

		if (!empty($this->feedUri)) {
			return $this->feedUri;
		}

		return parent::getURI();
	}

	public function getName() {

		if (!empty($this->feedName)) {
			return $this->feedName . ' - YouTube Community Tab';
		}

		return parent::getName();
	}

	/**
	 * Build Community URI
	 */
	private function buildCommunityUri($value, $type) {
		return self::URI . '/' . $type . '/' . $value . '/community';
	}

	/**
	 * Extract JSON from page
	 */
	private function extractJson($html) {

		if (!preg_match($this->jsonRegex, $html, $parts)) {
			returnServerError('Failed to extract data from page');
		}

		$data = json_decode($parts[1]);

		if ($data === false) {
			returnServerError('Failed to decode extracted data');
		}

		return $data;
	}

	/**
	 * Check if channel has a community tab
	 */
	private function hasCommunityTab($json) {

		foreach ($json->contents->twoColumnBrowseResultsRenderer->tabs as $tab) {
			if (isset($tab->tabRenderer) && $tab->tabRenderer->title === 'Community') {
				return true;
			}
		}

		return false;
	}

	/**
	 * Get community tab posts
	 */
	private function getCommunityPosts($json) {

		foreach ($json->contents->twoColumnBrowseResultsRenderer->tabs as $tab) {
			if ($tab->tabRenderer->title === 'Community') {
				return $tab->tabRenderer->content->sectionListRenderer->contents[0]->itemSectionRenderer->contents;
			}
		}
	}

	/**
	 * Get text content for a post
	 */
	private function getText($runs) {
		$text = '';

		foreach ($runs as $part) {
			$text .= $this->formatUrls($part->text);
		}

		return nl2br($text);
	}

	/**
	 * Get attachments for posts
	 */
	private function getAttachments($details) {
		$content = '';

		if (isset($details->backstageAttachment)) {
			$attachments = $details->backstageAttachment;

			// Video
			if (isset($attachments->videoRenderer) && isset($attachments->videoRenderer->videoId)) {
				if (empty($this->itemTitle)) {
					$this->itemTitle = $this->feedName . ' posted a video';
				}

				$content = <<<EOD
<iframe width="100%" height="410" src="https://www.youtube.com/embed/{$attachments->videoRenderer->videoId}" 
frameborder="0" allow="encrypted-media;" allowfullscreen></iframe>
EOD;
			}

			// Image
			if (isset($attachments->backstageImageRenderer)) {
				if (empty($this->itemTitle)) {
					$this->itemTitle = $this->feedName . ' posted an image';
				}

				$lastThumb = end($attachments->backstageImageRenderer->image->thumbnails);

				$content = <<<EOD
<p><img src="{$lastThumb->url}"></p>
EOD;
			}

			// Poll
			if (isset($attachments->pollRenderer)) {
				if (empty($this->itemTitle)) {
					$this->itemTitle = $this->feedName . ' posted a poll';
				}

				$pollChoices = '';

				foreach ($attachments->pollRenderer->choices as $choice) {
					$pollChoices .= <<<EOD
<li>{$choice->text->runs[0]->text}</li>
EOD;
				}

				$content = <<<EOD
<hr><p>Poll ({$attachments->pollRenderer->totalVotes->simpleText})<br><ul>{$pollChoices}</ul><p>
EOD;
			}
		}

		return $content;
	}

	/*
		Ellipsis text for title
	*/
	private function ellipsisTitle($text) {
		$length = 100;

		if (strlen($text) > $length) {
			$text = explode('<br>', wordwrap($text, $length, '<br>'));
			return $text[0] . '...';
		}

		return $text;
	}

	private function formatUrls($content) {
		return preg_replace(
			'/(http[s]{0,1}\:\/\/[a-zA-Z0-9.\/\?\&=\-_]{4,})/ims',
			'<a target="_blank" href="$1" target="_blank">$1</a> ',
			$content
		);
	}
}