フィードをパースするクラス

FeedParser

<?php

/**
 * Copyright (c) 2012 okumin, http://okumin.com/
 * 
 * Permission is hereby granted, free of charge, to any person obtaining
 * a copy of this software and associated documentation files (the
 * "Software"), to deal in the Software without restriction, including
 * without limitation the rights to use, copy, modify, merge, publish,
 * distribute, sublicense, and/or sell copies of the Software, and to
 * permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 * 
 * The above copyright notice and this permission notice shall be
 * included in all copies or substantial portions of the Software.
 * 
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
 * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE
 * LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION
 * OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION
 * WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
 */

class FeedParser
{
	const RSS1 = 0; // RSS1.0
	const RSS2 = 1; // RSS2.0
	const ATOM = 2; // Atom

	// フィードをパースして記事を配列で返す
	// 引数$feedにはフィードの文字列をそのまま指定
	// 引数$errorReportingがFALSEの場合、simplexml_load_stringによるWarningエラーは出力されない
	public static function parseFeed($feed, $errorReporting = FALSE){
		if(!$errorReporting){
			libxml_use_internal_errors(TRUE); // Warningエラーを抑制
		}
		$xml = simplexml_load_string($feed, 'SimpleXMLElement', LIBXML_NOCDATA);
		if(!$errorReporting){
			$warnings = libxml_get_errors();
			libxml_use_internal_errors(FALSE);
		}
		if($xml === FALSE || $errorReporting && count($warnings)){
			throw new FeedParserException('parseFeed: 入力されたフィードのデータからオブジェクトを作成できませんでした。フィードのフォーマットが不正な可能性があります。');
		}
		
		$format = self::checkFeedFormat($xml);
		if($format === self::RSS1){
			return self::parseRss1($xml);
		}elseif($format === self::RSS2){
			return self::parseRss2($xml);
		}elseif($format === self::ATOM){
			return self::parseAtom($xml);
		}
	}
	
	private static function checkFeedFormat($xml){
		if($xml->getName() === 'RDF'){
			return self::RSS1;
		}elseif($xml->getName() === 'rss'){
			return self::RSS2;
		}elseif($xml->getName() === 'feed'){
			return self::ATOM;
		}else{
			throw new FeedParserException('checkFeedFormat: 対応していないフォーマットのフィードが入力されました。扱えるフォーマットはRSS1.0、RSS2.0、Atomです。');
		}
	}
	
	private static function parseRss1($xml){
		$result = array();
		foreach($xml->item as $value){
			if(!isset($value->title, $value->link, $value->children('dc', TRUE)->date)){
				continue;
			}
			$result[] = array(
				'title' => (string) $value->title,
				'link' => (string) $value->link,
				'datetime' => (string) $value->children('dc', TRUE)->date,
			);
		}
		return $result;
	}
	
	private static function parseRss2($xml){
		$result = array();
		foreach($xml->channel->item as $value){
			if(isset($value->pubDate)){
				$datetime = $value->pubDate;
			}elseif(isset($value->children('dc', TRUE)->date)){
				$datetime = $value->children('dc', TRUE)->date;
			}else{
				$datetime = NULL;
			}
			if(!isset($value->title, $value->link, $datetime)){
				continue;
			}
			$result[] = array(
				'title' => (string) $value->title,
				'link' => (string) $value->link,
				'datetime' => (string) $datetime,
			);
		}
		return $result;
	}
	
	private static function parseAtom($xml){
		$result = array();
		foreach($xml as $value){
			if($value->getName() !== 'entry'){
				continue;
			}
			if(isset($value->issued)){
				$datetime = $value->issued;
			}elseif($value->published){
				$datetime = $value->published;
			}else{
				$datetime = NULL;
			}
			if(!isset($value->title, $value->link->attributes()->href, $datetime)){
				continue;
			}
			$result[] = array(
				'title' => (string) $value->title,
				'link' => (string) $value->link->attributes()->href,
				'datetime' => (string) $datetime,
			);
		}
		return $result;
	}
}

class FeedParserException extends Exception{}