shimmie2/ext/ban_words/main.php

<?php
/*
 * Name: Comment Word Ban
 * Author: Shish <webmaster@shishnet.org>
 * Link: http://code.shishnet.org/shimmie2/
 * License: GPLv2
 * Description: For stopping spam and other comment abuse
 * Documentation:
 *  Allows an administrator to ban certain words
 *  from comments. This can be a very simple but effective way
 *  of stopping spam; just add "viagra", "porn", etc to the
 *  banned words list.
 *  <p>Regex bans are also supported, allowing more complicated
 *  bans like <code>/http:.*\.cn\//</code> to block links to
 *  chinese websites, or <code>/.*?http.*?http.*?http.*?http.*?/</code>
 *  to block comments with four (or more) links in.
 *  <p>Note that for non-regex matches, only whole words are
 *  matched, eg banning "sex" would block the comment "get free
 *  sex call this number", but allow "This is a photo of Bob
 *  from Essex"
 */

class BanWords extends Extension {
	public function onInitExt(InitExtEvent $event) {
		global $config;
		$config->set_default_string('banned_words', "
a href=
anal
blowjob
/buy-.*-online/
casino
cialis
doors.txt
fuck
hot video
kaboodle.com
lesbian
nexium
penis
/pokerst.*/
pornhub
porno
purchase
sex
sex tape
spinnenwerk.de
thx for all
TRAMADOL
ultram
very nice site
viagra
xanax
");
	}

	public function onCommentPosting(CommentPostingEvent $event) {
		global $user;
		if(!$user->can("bypass_comment_checks")) {
			$this->test_text($event->comment, new CommentPostingException("Comment contains banned terms"));
		}
	}

	public function onSourceSet(SourceSetEvent $event) {
		$this->test_text($event->source, new SCoreException("Source contains banned terms"));
	}

	public function onTagSet(TagSetEvent $event) {
		$this->test_text(Tag::implode($event->tags), new SCoreException("Tags contain banned terms"));
	}

	public function onSetupBuilding(SetupBuildingEvent $event) {
		$sb = new SetupBlock("Banned Phrases");
		$sb->add_label("One per line, lines that start with slashes are treated as regex<br/>");
		$sb->add_longtext_option("banned_words");
		$failed = array();
		foreach($this->get_words() as $word) {
			if($word[0] == '/') {
				if(preg_match($word, "") === false) {
					$failed[] = $word;
				}
			}
		}
		if($failed) {
			$sb->add_label("Failed regexes: ".join(", ", $failed));
		}
		$event->panel->add_block($sb);
	}

	/**
	 * Throws if the comment contains banned words.
	 */
	private function test_text(string $comment, Exception $ex): void {
		$comment = strtolower($comment);

		foreach($this->get_words() as $word) {
			if($word[0] == '/') {
				// lines that start with slash are regex
				if(preg_match($word, $comment) === 1) {
					throw $ex;
				}
			}
			else {
				// other words are literal
				if(strpos($comment, $word) !== false) {
					throw $ex;
				}
			}
		}
	}

	private function get_words(): array {
		global $config;
		$words = array();

		$banned = $config->get_string("banned_words");
		foreach(explode("\n", $banned) as $word) {
			$word = trim(strtolower($word));
			if(strlen($word) == 0) {
				// line is blank
				continue;
			}
			$words[] = $word;
		}

		return $words;
	}

	public function get_priority(): int {return 30;}
}