<?php
/* rss-bridge library.
Foundation functions for rss-bridge project.
See https://github.com/sebsauvage/rss-bridge
Licence: Public domain.
*/
ini_set('user_agent', 'Mozilla/5.0 (X11; Linux x86_64; rv:20.0) Gecko/20100101 Firefox/20.0');
date_default_timezone_set('UTC');
error_reporting(0);
ini_set('display_errors','1'); error_reporting(E_ALL); // For debugging only.
define('CACHEDIR','cache/'); // Directory containing cache files. Do not forget trailing slash.
define('CHARSET', 'UTF-8');
define('SimpleDomLib', 'vendor/simplehtmldom/simple_html_dom.php');
ob_start();
// Create cache directory if it does not exist.
if (!is_dir(CACHEDIR)) { mkdir(CACHEDIR,0705); chmod(CACHEDIR,0705); }
// Import DOM library.
if (!file_exists(SimpleDomLib))
{
header('HTTP/1.1 500 Internal Server Error');
header('Content-Type: text/plain');
die('"PHP Simple HTML DOM Parser" is missing. Get it from http://simplehtmldom.sourceforge.net and place the script "simple_html_dom.php" in the same folder to allow me to work.');
}
require_once(SimpleDomLib);
/**
* Abstract RSSBridge class on which all bridges are build upon.
* It provides utility methods (cache, ATOM feed building...)
*/
abstract class RssBridgeAbstractClass {
/**
* $items is an array of dictionnaries. Each subclass must fill this array when collectData() is called.
* eg. $items = array( array('uri'=>'http://foo.bar', 'title'=>'My beautiful foobar', 'content'='Hello, <b>world !</b>','timestamp'=>'1375864834'),
* array('uri'=>'http://toto.com', 'title'=>'Welcome to toto', 'content'='What is this website about ?','timestamp'=>'1375868313')
* )
* Keys in dictionnaries:
* uri (string;mandatory) = The URI the item points to.
* title (string;mandatory) = Title of item
* content (string;optionnal) = item content (usually HTML code)
* timestamp (string;optionnal) = item date. Must be in EPOCH format.
* Other keys can be added, but will be ignored.
* $items will be used to build the ATOM feed, json and other outputs.
*/
public $items;
private $contentType; // MIME type returned to browser.
/**
* Sets the content-type returns to browser.
*
* @param string Content-type returns to browser - Example: $this->setContentType('text/html; charset=UTF-8')
* @return this
*/
private function setContentType($value){
$this->contentType = $value;
header('Content-Type: '.$value);
return $this;
}
/**
* collectData() will be called to ask the bridge to go collect data on the net.
* All derived classes must implement this method.
* This method must fill $this->items with collected items.
* @param mixed $request : The incoming request (=$_GET). This can be used or ignored by the bridge.
*/
abstract protected function collectData($request);
/**
* Returns a HTTP error to user, with a message.
* Example: $this->returnError(404, 'no results.');
* @param integer $code
* @param string $message
*/
protected function returnError($code, $message){
$errors = array(
400 => 'Bad Request',
404 => 'Not Found',
501 => 'Not Implemented',
);
header('HTTP/1.1 ' . $code . ( isset($errors[$code]) ? ' ' . $errors[$code] : ''));
header('Content-Type: text/plain;charset=' . CHARSET);
die('ERROR : ' . $message);
}
/**
* Builds an ATOM feed from $this->items and return it to browser.
*/
private function returnATOM(){
$this->setContentType('application/atom+xml; charset=' . CHARSET);
$https = ( isset($_SERVER['HTTPS']) && $_SERVER['HTTPS'] == 'on' ? 's' : '' );
$httpHost = isset($_SERVER['HTTP_HOST']) ? $_SERVER['HTTP_HOST'] : '';
$httpInfo = isset($_SERVER['PATH_INFO']) ? $_SERVER['PATH_INFO'] : '';
echo '<?xml version="1.0" encoding="UTF-8"?><feed xmlns="http://www.w3.org/2005/Atom" xmlns:thr="http://purl.org/syndication/thread/1.0" xml:lang="en-US">'."\n";
echo '<title type="text">'.htmlspecialchars($this->bridgeName).'</title>'."\n";
echo '<id>http' . $https . '://' . $httpHost . $httpInfo . './</id>'."\n";
echo '<updated></updated>'."\n"; // FIXME
echo '<link rel="alternate" type="text/html" href="'.htmlspecialchars($this->bridgeURI).'" />'."\n";
echo '<link rel="self" href="http'.$https.'://' . $httpHost . htmlentities($_SERVER['REQUEST_URI']).'" />'."\n"."\n";
foreach($this->items as $item) {
echo '<entry><author><name>'.htmlspecialchars($this->bridgeName).'</name><uri>'.htmlspecialchars($this->bridgeURI).'</uri></author>'."\n";
echo '<title type="html"><![CDATA['.$item['title'].']]></title>'."\n";
echo '<link rel="alternate" type="text/html" href="'.$item['uri'].'" />'."\n";
echo '<id>'.$item['uri'].'</id>'."\n";
echo '<updated>' . ( isset($item['timestamp']) ? date(DATE_ATOM, $item['timestamp']) : '' ) . '</updated>'."\n";
echo '<content type="html">' . ( isset($item['content']) ? '<![CDATA[' . $item['content'] . ']]>' : '') . '</content>'."\n";
// FIXME: Security: Disable Javascript ?
echo '</entry>'."\n\n";
}
echo '</feed>';
}
private function returnHTML(){
$this->setContentType('text/html; charset=' . CHARSET);
echo '<html><head><title>'.htmlspecialchars($this->bridgeName).'</title>';
echo '<style>body{font-family:"Trebuchet MS",Verdana,Arial,Helvetica,sans-serif;font-size:10pt;background-color:#aaa;}div.rssitem{border:1px solid black;padding:5px;margin:10px;background-color:#fff;}</style></head><body>';
echo '<h1>'.htmlspecialchars($this->bridgeName).'</h1>';
foreach($this->items as $item) {
echo '<div class="rssitem"><h2><a href="'.$item['uri'].'">'.htmlspecialchars(strip_tags($item['title'])).'</a></h2>';
if (isset($item['timestamp'])) { echo '<small>'.date(DATE_ATOM, $item['timestamp']).'</small>'; }
if (isset($item['content'])) { echo '<p>'.$item['content'].'</p>'; }
echo "</div>\n\n";
}
echo '</body></html>';
}
/**
* Builds a JSON string from $this->items and return it to browser.
*/
private function returnJSON(){
$this->setContentType('application/json');
echo json_encode($this->items);
}
/**
* Returns $this->items as raw php data.
*/
private function returnPlaintext(){
$this->setContentType('text/plain;charset=' . CHARSET);
print_r($this->items);
}
/**
* Start processing request and return response to browser.
*/
public function process(){
$this->serveCachedVersion();
// Cache file does not exists or has expired: We re-fetch the results and cache it.
$this->collectData($_REQUEST);
if (empty($this->items)) { $this->returnError(404, 'no results.'); }
$format = isset($_REQUEST['format']) ? $_REQUEST['format'] : 'atom';
switch($format) {
case 'plaintext':
$this->returnPlaintext();
break;
case 'json':
$this->returnJSON();
break;
case 'html':
$this->returnHTML();
break;
default:
$this->returnATOM();
}
$this->storeReponseInCache();
}
private function getCacheName(){
if( !isset($_REQUEST) ){
$this->returnError(501, 'WTF ?');
}
$stringToEncode = $_SERVER['REQUEST_URI'] . http_build_query($_REQUEST);
return CACHEDIR.hash('sha1',$stringToEncode).'.cache';
}
/**
* Returns the cached version of current request URI directly to the browser
* if it exists and if cache has not expired.
* Continues execution no cached version available.
*/
private function serveCachedVersion(){
// See if cache exists for this request
$cachefile = $this->getCacheName(); // Cache path and filename
if (file_exists($cachefile)) { // The cache file exists.
if (time() - ($this->cacheDuration*60) < filemtime($cachefile)) { // Cache file has not expired. Serve it.
$data = json_decode(file_get_contents($cachefile),true);
header('Content-Type: '.$data['Content-Type']); // Send proper MIME Type
header('X-Cached-Version: '.date(DATE_ATOM, filemtime($cachefile)));
echo $data['data'];
exit();
}
}
}
/**
* Stores currently generated page in cache.
* @return this
*/
private function storeReponseInCache(){
$cachefile = $this->getCacheName(); // Cache path and filename
$data = array('data'=>ob_get_contents(), 'Content-Type'=>$this->contentType);
file_put_contents($cachefile,json_encode($data));
ob_end_flush();
return $this;
}
}