[FilterBridge] Initial implementation of basic title permit and block

See the comment https://github.com/RSS-Bridge/rss-bridge/issues/402#issuecomment-305982306

Split off from https://github.com/RSS-Bridge/rss-bridge/pull/535

bridges/FilterBridge.php

@@ -0,0 +1,77 @@
+<?php
+
+class FilterBridge extends FeedExpander {
+
+	const MAINTAINER = 'Frenzie';
+	const NAME = 'Filter';
+	const CACHE_TIMEOUT = 3600; // 1h
+	const DESCRIPTION = 'Filters a feed of your choice';
+
+	const PARAMETERS = array(array(
+		'url' => array(
+			'name' => 'Feed URL',
+			'required' => true,
+		),
+		'filter' => array(
+			'name' => 'Filter item title (regular expression)',
+			'required' => false,
+		),
+		'filter_type' => array(
+			'name' => 'Filter type',
+			'type' => 'list',
+			'required' => false,
+			'values' => array(
+				'Permit' => 'permit',
+				'Block' => 'block',
+			),
+			'defaultValue' => 'permit',
+		),
+	));
+
+	protected function parseItem($newItem){
+		$item = parent::parseItem($newItem);
+
+		switch(true){
+		case $this->getFilterType() === 'permit':
+			if (preg_match($this->getFilter(), $item['title'])) {
+				return $item;
+			}
+			break;
+		case $this->getFilterType() === 'block':
+			if (!preg_match($this->getFilter(), $item['title'])) {
+				return $item;
+			}
+			break;
+		}
+		return null;
+	}
+
+	protected function getFilter(){
+		return '/' . $this->getInput('filter') . '/';
+	}
+
+	protected function getFilterType(){
+		return $this->getInput('filter_type');
+	}
+
+	public function getURI(){
+		$url = $this->getInput('url');
+
+		if(empty($url)){
+			$url = parent::getURI();
+		}
+		return $url;
+	}
+
+	public function collectData(){
+		if($this->getInput('url') && substr($this->getInput('url'), 0, strlen('http')) !== 'http'){
+			// just in case someone find a way to access local files by playing with the url
+			returnClientError('The url parameter must either refer to http or https protocol.');
+		}
+		try{
+			$this->collectExpandableDatas($this->getURI());
+		}catch (HttpException $e){
+			$this->collectExpandableDatas($this->getURI());
+		}
+	}
+}