<?php
# -- BEGIN LICENSE BLOCK ---------------------------------------
#
# This file is part of Dotclear 2.
#
# Copyright (c) 2003-2013 Olivier Meunier & Association Dotclear
# Licensed under the GPL version 2.0 license.
# See LICENSE file or
# http://www.gnu.org/licenses/old-licenses/gpl-2.0.html
#
# -- END LICENSE BLOCK -----------------------------------------
if (!defined('DC_RC_PATH')) { return; }

/**
@ingroup DC_CORE
@brief Trackbacks/Pingbacks sender and server

Sends and receives trackbacks/pingbacks. Also handles trackbacks/pingbacks auto discovery.
*/
class dcTrackback
{
	public $core;		///< <b>dcCore</b> dcCore instance
	public $table;		///< <b>string</b> done pings table name

	/**
	Object constructor

	@param	core		<b>dcCore</b>		dcCore instance
	*/
	public function __construct($core)
	{
		$this->core =& $core;
		$this->con =& $this->core->con;
		$this->table = $this->core->prefix.'ping';
	}

	/// @name Send
	//@{
	/**
	Get all pings sent for a given post.

	@param	post_id	<b>integer</b>		Post ID
	@return	<b>record</b>
	*/
	public function getPostPings($post_id)
	{
		$strReq = 'SELECT ping_url, ping_dt '.
				'FROM '.$this->table.' '.
				'WHERE post_id = '.(integer) $post_id;

		return $this->con->select($strReq);
	}

	/**
	Sends a ping to given <var>$url</var>.

	@param	url			<b>string</b>		URL to ping
	@param	post_id		<b>integer</b>		Post ID
	@param	post_title	<b>string</b>		Post title
	@param	post_excerpt	<b>string</b>		Post excerpt
	@param	post_url		<b>string</b>		Post URL
	*/
	public function ping($url,$post_id,$post_title,$post_excerpt,$post_url)
	{
		if ($this->core->blog === null) {
			return false;
		}

		$post_id = (integer) $post_id;

		# Check for previously done trackback
		$strReq = 'SELECT post_id, ping_url FROM '.$this->table.' '.
				'WHERE post_id = '.$post_id.' '.
				"AND ping_url = '".$this->con->escape($url)."' ";

		$rs = $this->con->select($strReq);

		if (!$rs->isEmpty()) {
			throw new Exception(sprintf(__('%s has still been pinged'),$url));
		}

		$ping_parts = explode('|',$url);
		# Maybe a webmention
		if (count($ping_parts) == 3) {
			$payload = http_build_query(array(
				'source' => $post_url,
				'target' => $ping_parts[1]
			));

			try {
				$http = self::initHttp($ping_parts[0],$path);
				$http->setMoreHeader('Content-Type: application/x-www-form-urlencoded');
				$http->post($path,$payload,'UTF-8');

				# Read response status
				$status = $http->getStatus();
				$ping_error = '0';
			}
			catch (Exception $e) {
				throw new Exception(__('Unable to ping URL'));
			}

			if (!in_array($status,array('200','201','202'))) {
				$ping_error = $http->getStatus();
				$ping_msg = __('Bad server response code');
			}
		}
		# No, let's walk by the trackback way
		elseif (count($ping_parts) < 2) {
			$data = array(
				'title' => $post_title,
				'excerpt' => $post_excerpt,
				'url' => $post_url,
				'blog_name' => trim(html::escapeHTML(html::clean($this->core->blog->name)))
				//,'__debug' => false
			);

			# Ping
			try {
				$http = self::initHttp($url,$path);
				$http->post($path,$data,'UTF-8');
				$res = $http->getContent();
			}
			catch (Exception $e) {
				throw new Exception(__('Unable to ping URL'));
			}

			$pattern =
			'|<response>.*<error>(.*)</error>(.*)'.
			'(<message>(.*)</message>(.*))?'.
			'</response>|msU';

			if (!preg_match($pattern,$res,$match)) {
				throw new Exception(sprintf(__('%s is not a ping URL'),$url));
			}

			$ping_error = trim($match[1]);
			$ping_msg = (!empty($match[4])) ? $match[4] : '';
		}
		# Damnit ! Let's play pingback
		else {
			try {
				$xmlrpc = new xmlrpcClient($ping_parts[0]);
				$res = $xmlrpc->query('pingback.ping', $post_url, $ping_parts[1]);
				$ping_error = '0';
			}
			catch (xmlrpcException $e) {
				$ping_error = $e->getCode();
				$ping_msg = $e->getMessage();
			}
			catch (Exception $e) {
				throw new Exception(__('Unable to ping URL'));
			}
		}

		if ($ping_error != '0') {
			throw new Exception(sprintf(__('%s, ping error:'),$url).' '.$ping_msg);
		}
		else {
			# Notify ping result in database
			$cur = $this->con->openCursor($this->table);
			$cur->post_id = $post_id;
			$cur->ping_url = $url;
			$cur->ping_dt = date('Y-m-d H:i:s');

			$cur->insert();
		}
	}
	//@}

	/// @name Receive
	//@{
	/**
	Receives a trackback and insert it as a comment of given post.

	@param	post_id		<b>integer</b>		Post ID
	*/
	public function receiveTrackback($post_id)
	{
		header('Content-Type: text/xml; charset=UTF-8');
		if (empty($_POST)) {
			http::head(405,'Method Not Allowed');
			echo
			'<?xml version="1.0" encoding="utf-8"?>'."\n".
			"<response>\n".
			"  <error>1</error>\n".
			"  <message>POST request needed</message>\n".
			"</response>";
			return;
		}

		$post_id = (integer) $post_id;

		$title = !empty($_POST['title']) ? $_POST['title'] : '';
		$excerpt = !empty($_POST['excerpt']) ? $_POST['excerpt'] : '';
		$url = !empty($_POST['url']) ? $_POST['url'] : '';
		$blog_name = !empty($_POST['blog_name']) ? $_POST['blog_name'] : '';
		$charset = '';
		$comment = '';

		$err = false;
		$msg = '';

		if ($this->core->blog === null) {
			$err = true;
			$msg = 'No blog.';
		}
		elseif ($url == '') {
			$err = true;
			$msg = 'URL parameter is required.';
		}
		elseif ($blog_name == '') {
			$err = true;
			$msg = 'Blog name is required.';
		}

		if (!$err) {
			$post = $this->core->blog->getPosts(array('post_id'=>$post_id,'post_type'=>''));

			if ($post->isEmpty()) {
				$err = true;
				$msg = 'No such post.';
			}
			elseif (!$post->trackbacksActive()) {
				$err = true;
				$msg = 'Trackbacks are not allowed for this post or weblog.';
			}

			$url = trim(html::clean($url));
			if ($this->pingAlreadyDone($post->post_id,$url)) {
				$err = true;
				$msg = 'The trackback has already been registered';
			}
		}

		if (!$err) {
			$charset = self::getCharsetFromRequest();

			if (!$charset) {
				$charset = self::detectCharset($title.' '.$excerpt.' '.$blog_name);
			}

			if (strtolower($charset) != 'utf-8') {
				$title = iconv($charset,'UTF-8',$title);
				$excerpt = iconv($charset,'UTF-8',$excerpt);
				$blog_name = iconv($charset,'UTF-8',$blog_name);
			}

			$title = trim(html::clean($title));
			$title = html::decodeEntities($title);
			$title = html::escapeHTML($title);
			$title = text::cutString($title,60);

			$excerpt = trim(html::clean($excerpt));
			$excerpt = html::decodeEntities($excerpt);
			$excerpt = preg_replace('/\s+/ms',' ',$excerpt);
			$excerpt = text::cutString($excerpt,252);
			$excerpt = html::escapeHTML($excerpt).'...';

			$blog_name = trim(html::clean($blog_name));
			$blog_name = html::decodeEntities($blog_name);
			$blog_name = html::escapeHTML($blog_name);
			$blog_name = text::cutString($blog_name,60);

			try {
				$this->addBacklink($post_id,$url,$blog_name,$title,$excerpt,$comment);
			}
			catch (Exception $e) {
				$err = 1;
				$msg = 'Something went wrong : '.$e->getMessage();
			}
		}

		$resp =
		'<?xml version="1.0" encoding="utf-8"?>'."\n".
		"<response>\n".
		'  <error>'.(integer) $err."</error>\n";

		if ($msg) {
			$resp .= '  <message>'.$msg."</message>\n";
		}

		if (!empty($_POST['__debug'])) {
			$resp .=
			"  <debug>\n".
			'    <title>'.$title."</title>\n".
			'    <excerpt>'.$excerpt."</excerpt>\n".
			'    <url>'.$url."</url>\n".
			'    <blog_name>'.$blog_name."</blog_name>\n".
			'    <charset>'.$charset."</charset>\n".
			'    <comment>'.$comment."</comment>\n".
			"  </debug>\n";
		}

		echo	$resp."</response>";
	}

	/**
	Receives a pingback and insert it as a comment of given post.

	@param	from_url		<b>string</b>		Source URL
	@param	to_url			<b>string</b>		Target URL
	*/
	public function receivePingback($from_url,$to_url)
	{
		try {
			$posts = $this->getTargetPost($to_url);

			if ($this->pingAlreadyDone($posts->post_id,$from_url)) {
				throw new Exception(__('Don\'t repeat yourself, please.'), 48);
			}

			$remote_content = $this->getRemoteContent($from_url);

			# We want a title...
			if (!preg_match('!<title>([^<].*?)</title>!mis',$remote_content,$m)) {
				throw new Exception(__('Where\'s your title?'), 0);
			}
			$title = trim(html::clean($m[1]));
			$title = html::decodeEntities($title);
			$title = html::escapeHTML($title);
			$title = text::cutString($title,60);

			preg_match('!<body[^>]*?>(.*)?</body>!msi',$remote_content,$m);
			$source = $m[1];
			$source = preg_replace('![\r\n\s]+!ms',' ',$source);
			$source = preg_replace( "/<\/*(h\d|p|th|td|li|dt|dd|pre|caption|input|textarea|button)[^>]*>/","\n\n",$source );
			$source = strip_tags($source,'<a>');
			$source = explode("\n\n",$source);

			$excerpt = '';
			foreach ($source as $line) {
				if (strpos($line, $to_url) !== false) {
					if (preg_match("!<a[^>]+?".$to_url."[^>]*>([^>]+?)</a>!",$line,$m)) {
						$excerpt = strip_tags($line);
						break;
					}
				}
			}
			if ($excerpt) {
				$excerpt = '(&#8230;) '.text::cutString(html::escapeHTML($excerpt),200).' (&#8230;)';
			}
			else {
				$excerpt = '(&#8230;)';
			}

			$this->addBacklink($posts->post_id,$from_url,'',$title,$excerpt,$comment);
		}
		catch (Exception $e) {
			throw new Exception(__('Sorry, an internal problem has occured.'),0);
		}

		return __('Thanks, mate. It was a pleasure.');
	}

	/**
	Receives a webmention and insert it as a comment of given post.

	NB: plugin Fair Trackback check source content to find url.

	@return	<b>null</b>	Null on success, else throw an exception
	*/
	public function receiveWebmention()
	{
		$err = $post_id = false;
		header('Content-Type: text/html; charset=UTF-8');

		try {
			# Check if post and target are valid URL
			if (empty($_POST['source']) || empty($_POST['target'])) {
				throw new Exception('Source or target is not valid',0);
			}

			$from_url = urldecode($_POST['source']);
			$to_url = urldecode($_POST['target']);

			self::checkURLs($from_url,$to_url);

			# Try to find post
			$posts = $this->getTargetPost($to_url);
			$post_id = $posts->post_id;

			# Check if it's an updated mention
			if ($this->pingAlreadyDone($post_id,$from_url)) {
				$this->delBacklink($post_id,$from_url);
			}

			# Create a comment for received webmention
			$remote_content = $this->getRemoteContent($from_url);

			# We want a title...
			if (!preg_match('!<title>([^<].*?)</title>!mis',$remote_content,$m)) {
				throw new Exception(__('Where\'s your title?'), 0);
			}
			$title = trim(html::clean($m[1]));
			$title = html::decodeEntities($title);
			$title = html::escapeHTML($title);
			$title = text::cutString($title,60);

			preg_match('!<body[^>]*?>(.*)?</body>!msi',$remote_content,$m);
			$source = $m[1];
			$source = preg_replace('![\r\n\s]+!ms',' ',$source);
			$source = preg_replace( "/<\/*(h\d|p|th|td|li|dt|dd|pre|caption|input|textarea|button)[^>]*>/","\n\n",$source );
			$source = strip_tags($source,'<a>');
			$source = explode("\n\n",$source);

			$excerpt = '';
			foreach ($source as $line) {
				if (strpos($line, $to_url) !== false) {
					if (preg_match("!<a[^>]+?".$to_url."[^>]*>([^>]+?)</a>!",$line,$m)) {
						$excerpt = strip_tags($line);
						break;
					}
				}
			}
			if ($excerpt) {
				$excerpt = '(&#8230;) '.text::cutString(html::escapeHTML($excerpt),200).' (&#8230;)';
			}
			else {
				$excerpt = '(&#8230;)';
			}

			$this->addBacklink($post_id,$from_url,'',$title,$excerpt,$comment);

			# All done, thanks
			$code = $this->core->blog->settings->system->trackbacks_pub ? 200 : 202;
			http::head($code);
			return;
		}
		catch (Exception $e) {
			$err = $e->getMessage();
		}

		http::head(400);
		echo $err ?: 'Something went wrong.';
		return;
	}

	/**
	Check if a post previously received a ping a from an URL.

	@param	post_id	<b>integer</b>		Post ID
	@param	from_url	<b>string</b>		Source URL
	@return	<b>boolean</b>
	*/
	private function pingAlreadyDone($post_id,$from_url)
	{
		$params = array(
			'post_id' => $post_id,
			'comment_site' => $from_url,
			'comment_trackback' => 1,
		);

		$rs = $this->core->blog->getComments($params,true);
		if ($rs && !$rs->isEmpty()) {
			return ($rs->f(0));
		}

		return false;
	}

	/**
	Create a comment marked as trackback for a given post.

	@param	post_id	<b>integer</b>		Post ID
	@param	url		<b>string</b>		Discovered URL
	@param	blog name	<b>string</b>		Source blog name
	@param	title	<b>string</b>		Comment title
	@param	excerpt	<b>string</b>		Source excerpt
	@param	comment	<b>string</b>		Comment content
	*/
	private function addBacklink($post_id,$url,$blog_name,$title,$excerpt,&$comment)
	{
		if (empty($blog_name)) {
			// Let use title as text link for this backlink
			$blog_name = ($title ?: 'Anonymous blog');
		}

		$comment =
		"<!-- TB -->\n".
		'<p><strong>'.($title ?: $blog_name)."</strong></p>\n".
		'<p>'.$excerpt.'</p>';

		$cur = $this->core->con->openCursor($this->core->prefix.'comment');
		$cur->comment_author = (string) $blog_name;
		$cur->comment_site = (string) $url;
		$cur->comment_content = (string) $comment;
		$cur->post_id = $post_id;
		$cur->comment_trackback = 1;
		$cur->comment_status = $this->core->blog->settings->system->trackbacks_pub ? 1 : -1;
		$cur->comment_ip = http::realIP();

		# --BEHAVIOR-- publicBeforeTrackbackCreate
		$this->core->callBehavior('publicBeforeTrackbackCreate',$cur);
		if ($cur->post_id) {
			$comment_id = $this->core->blog->addComment($cur);

			# --BEHAVIOR-- publicAfterTrackbackCreate
			$this->core->callBehavior('publicAfterTrackbackCreate',$cur,$comment_id);
		}
	}

	/**
	Delete previously received comment made from an URL for a given post.

	@param	post_id	<b>integer</b>		Post ID
	@param	url		<b>string</b>		Source URL
	*/
	private function delBacklink($post_id,$url)
	{
		$this->con->execute(
			'DELETE FROM '.$this->core->prefix.'comment '.
			'WHERE post_id = '.((integer) $post_id).' '.
			"AND comment_site = '".$this->core->con->escape((string) $url)."' ".
			'AND comment_trackback = 1 '
		);
	}

	/**
	Find Charset from HTTP headers.

	@param	header	<b>string</b>		Source header
	@return	<b>string</b>
	*/
	private static function getCharsetFromRequest($header = '')
	{
		if (!$header && isset($_SERVER['CONTENT_TYPE'])) {
			$header = $_SERVER['CONTENT_TYPE'];
		}

		if ($header) {
			if (preg_match('|charset=([a-zA-Z0-9-]+)|',$header,$m)) {
				return $m[1];
			}
		}

		return null;
	}

	/**
	Detect encoding.

	@param	content		<b>string</b>		Source URL
	@return	<b>string</b>
	*/
	private static function detectCharset($content)
	{
		return mb_detect_encoding($content,
				'UTF-8,ISO-8859-1,ISO-8859-2,ISO-8859-3,'.
				'ISO-8859-4,ISO-8859-5,ISO-8859-6,ISO-8859-7,ISO-8859-8,'.
				'ISO-8859-9,ISO-8859-10,ISO-8859-13,ISO-8859-14,ISO-8859-15');
	}

	/**
	Retreive local post from a given URL

	@param	to_url		<b>string</b>		Target URL
	@return	<b>string</b>
	*/
	private function getTargetPost($to_url)
	{
		$reg = '!^'.preg_quote($this->core->blog->url).'(.*)!';
		$type = $args = $next = '';

		# Are you dumb?
		if (!preg_match($reg,$to_url,$m)) {
			throw new Exception(__('Any chance you ping one of my contents? No? Really?'),0);
		}

		# Does the targeted URL look like a registered post type?
		$url_part = $m[1];
		$p_type = '';
		$post_types = $this->core->getPostTypes();
		foreach ($post_types as $k => $v) {
			$reg = '!^'.preg_quote(str_replace('%s','',$v['public_url'])).'(.*)!';
			if (preg_match($reg,$url_part,$n)) {
				$p_type = $k;
				$post_url = $n[1];
				break;
			}
		}

		if (empty($p_type)) {
			throw new Exception(__('Sorry but you can not ping this type of content.'),33);
		}

		# Time to see if we've got a winner...
		$params = array(
			'post_type' => $p_type,
			'post_url' => $post_url,
		);
		$posts = $this->core->blog->getPosts($params);

		# Missed!
		if ($posts->isEmpty()) {
			throw new Exception(__('Oops. Kinda "not found" stuff. Please check the target URL twice.'),33);
		}

		# Nice try. But, sorry, no.
		if (!$posts->trackbacksActive()) {
			throw new Exception(__('Sorry, dude. This entry does not accept pingback at the moment.'),33);
		}

		return $posts;
	}

	/**
	Returns content of a distant page

	@param	from_url		<b>string</b>		Target URL
	@return	<b>string</b>
	*/
	private function getRemoteContent($from_url)
	{
		$http = self::initHttp($from_url,$from_path);

		# First round : just to be sure the ping comes from an acceptable resource type.
		$http->setHeadersOnly(true);
		$http->get($from_path);
		$c_type = explode(';',$http->getHeader('content-type'));

		# Bad luck. Bye, bye...
		if (!in_array($c_type[0],array('text/html','application/xhtml+xml'))) {
			throw new Exception(__('Your source URL does not look like a supported content type. Sorry. Bye, bye!'),0);
		}

		# Second round : let's go fetch and parse the remote content
		$http->setHeadersOnly(false);
		$http->get($from_path);
		$remote_content = $http->getContent();

		# Convert content charset
		$charset = self::getCharsetFromRequest($http->getHeader('content-type'));
		if (!$charset) {
			$charset = self::detectCharset($remote_content);
		}
		if (strtolower($charset) != 'utf-8') {
			$remote_content = iconv($charset,'UTF-8',$remote_content);
		}

		return $remote_content;
	}
	//@}

	/// @name Discover
	//@{
	/**
	Returns an array containing all discovered trackbacks URLs in
	<var>$text</var>.

	@param	text		<b>string</b>		Input text
	@return	<b>array</b>
	*/
	public function discover($text)
	{
		$res = array();

		foreach ($this->getTextLinks($text) as $link)
		{
			if (($url = $this->getPingURL($link)) !== null) {
				$res[] = $url;
			}
		}

		return $res;
	}

	/**
	Find links into a text.

	@param	text		<b>string</b>		Text to scan
	@return	<b>array</b>
	*/
	private function getTextLinks($text)
	{
		$res = array();

		# href attribute on "a" tags
		if (preg_match_all('/<a ([^>]+)>/ms',$text,$match,PREG_SET_ORDER)) {
			for ($i = 0; $i<count($match); $i++)
			{
				if (preg_match('/href="((https?:\/)?\/[^"]+)"/ms',$match[$i][1],$matches)) {
					$res[$matches[1]] = 1;
				}
			}
		}
		unset($match);

		# cite attributes on "blockquote" and "q" tags
		if (preg_match_all('/<(blockquote|q) ([^>]+)>/ms',$text,$match,PREG_SET_ORDER)) {
			for ($i = 0; $i<count($match); $i++)
			{
				if (preg_match('/cite="((https?:\/)?\/[^"]+)"/ms',$match[$i][2],$matches)) {
					$res[$matches[1]] = 1;
				}
			}
		}

		return array_keys($res);
	}

	/**
	Check remote header/content to find api trace.

	@param	url		<b>string</b>		URL to scan
	@return	<b>string</b>
	*/
	private function getPingURL($url)
	{
		if (strpos($url,'/') === 0) {
			$url = http::getHost().$url;
		}

		try {
			$http = self::initHttp($url,$path);
			$http->get($path);
			$page_content = $http->getContent();
			$pb_url = $http->getHeader('x-pingback');
			$wm_url = $http->getHeader('link');
		}
		catch (Exception $e) {
			return false;
		}

		# Let's check for an elderly trackback data chunk...
		$pattern_rdf =
		'/<rdf:RDF.*?>.*?'.
		'<rdf:Description\s+(.*?)\/>'.
		'.*?<\/rdf:RDF>'.
		'/msi';

		preg_match_all($pattern_rdf,$page_content,$rdf_all,PREG_SET_ORDER);

		$url_path = parse_url($url, PHP_URL_PATH);
		$sanitized_url = str_replace($url_path, html::sanitizeURL($url_path),$url);

		for ($i=0; $i<count($rdf_all); $i++)
		{
			$rdf = $rdf_all[$i][1];
			if (preg_match('/dc:identifier="'.preg_quote($url,'/').'"/msi',$rdf) ||
				preg_match('/dc:identifier="'.preg_quote($sanitized_url,'/').'"/msi',$rdf)) {
				if (preg_match('/trackback:ping="(.*?)"/msi',$rdf,$tb_link)) {
					return $tb_link[1];
				}
			}
		}

		# No trackback ? OK, let see if we've got a X-Pingback header and it's a valid URL, it will be enough
		if ($pb_url && filter_var($pb_url,FILTER_VALIDATE_URL) && preg_match('!^https?:!',$pb_url)) {
			return $pb_url.'|'.$url;
		}

		# No X-Pingback header. A link rel=pingback, maybe ?
		$pattern_pingback = '!<link rel="pingback" href="(.*?)"( /)?>!msi';

		if (preg_match($pattern_pingback,$page_content,$m)) {
			$pb_url = $m[1];
			if (filter_var($pb_url,FILTER_VALIDATE_URL) && preg_match('!^https?:!',$pb_url)) {
				return $pb_url.'|'.$url;
			}
		}

		# Nothing, let's try webmention. Only support x/html content
		if ($wm_url) {
			$type = explode(';',$http->getHeader('content-type'));
			if (!in_array($type[0],array('text/html','application/xhtml+xml'))) {
				$wm_url = false;
			}
		}

		# Check HTTP headers for a Link: <ENDPOINT_URL>; rel="webmention"
		$wm_api = false;
		if ($wm_url) {
			if(preg_match('~<((?:https?://)?[^>]+)>; rel="?(?:https?://webmention.org/?|webmention)"?~',$wm_url,$match)) {
				if (filter_var($match[1],FILTER_VALIDATE_URL) && preg_match('!^https?:!',$match[1])) {
					$wm_api = $match[1];
				}
			}
		}

		# Else check content for <link href="ENDPOINT_URL" rel="webmention" />
		if ($wm_url && !$wm_api) {
			$content = preg_replace('/<!--(.*)-->/Us','',$page_content);
			if (preg_match('/<(?:link|a)[ ]+href="([^"]*)"[ ]+rel="[^" ]* ?webmention ?[^" ]*"[ ]*\/?>/i',$content,$match)
			 || preg_match('/<(?:link|a)[ ]+rel="[^" ]* ?webmention ?[^" ]*"[ ]+href="([^"]*)"[ ]*\/?>/i',$content,$match)) {
				$wm_api = $match[1];
			}
		}

		# We have a winner, let's add some tricks to make diference
		if ($wm_api) {
			return $wm_api.'|'.$url.'|webmention';
		}

		return null;
	}
	//@}

	/**
	HTTP helper.

	@param	url		<b>string</b>		URL
	@param	path		<b>string</b>		Path
	@return	<b>object</b>
	*/
	private static function initHttp($url,&$path)
	{
		$client = netHttp::initClient($url,$path);
		$client->setTimeout(5);
		$client->setUserAgent('Dotclear - http://www.dotclear.org/');
		$client->useGzip(false);
		$client->setPersistReferers(false);

		return $client;
	}

	/**
	URL helper.

	@param	from_url		<b>string</b>		URL a
	@param	to_url		<b>string</b>		URL b
	*/
	public static function checkURLs($from_url,$to_url)
	{
		if (!(filter_var($from_url,FILTER_VALIDATE_URL) && preg_match('!^https?://!',$from_url))) {
			throw new Exception(__('No valid source URL provided? Try again!'), 0);
		}

		if (!(filter_var($to_url,FILTER_VALIDATE_URL) && preg_match('!^https?://!',$to_url))) {
			throw new Exception(__('No valid target URL provided? Try again!'), 0);
		}

		if (html::sanitizeURL(urldecode($from_url)) == html::sanitizeURL(urldecode($to_url))) {
			throw new Exception(__('LOL!'), 0);
		}
	}
}
