Friendica Communications Platform (please note that this is a clone of the repository at github, issues are handled there) https://friendi.ca
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<?php
namespace Friendica\Util;
use Friendica\Core\Config;
use Friendica\DI;
/**
* @brief Proxy utilities class
*/
class Proxy
{
/**
* Default time to keep images in proxy storage
*/
const DEFAULT_TIME = 86400; // 1 Day
/**
* Sizes constants
*/
const SIZE_MICRO = 'micro';
const SIZE_THUMB = 'thumb';
const SIZE_SMALL = 'small';
const SIZE_MEDIUM = 'medium';
const SIZE_LARGE = 'large';
/**
* Accepted extensions
*
* @var array
* @todo Make this configurable?
*/
private static $extensions = [
'jpg',
'jpeg',
'gif',
'png',
];
/**
* @brief Private constructor
*/
private function __construct () {
// No instances from utilities classes
}
/**
* @brief Transform a remote URL into a local one.
*
* This function only performs the URL replacement on http URL and if the
* provided URL isn't local, "the isn't deactivated" (sic) and if the config
* system.proxy_disabled is set to false.
*
* @param string $url The URL to proxyfy
* @param bool $writemode Returns a local path the remote URL should be saved to
* @param string $size One of the ProxyUtils::SIZE_* constants
*
* @return string The proxyfied URL or relative path
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
public static function proxifyUrl($url, $writemode = false, $size = '')
{
// Get application instance
$a = DI::app();
// Trim URL first
$url = trim($url);
// Is no http in front of it?
/// @TODO To weak test for being a valid URL
if (substr($url, 0, 4) !== 'http') {
return $url;
}
// Only continue if it isn't a local image and the isn't deactivated
if (self::isLocalImage($url)) {
$url = str_replace(Strings::normaliseLink(DI::baseUrl()) . '/', DI::baseUrl() . '/', $url);
return $url;
}
// Is the proxy disabled?
if (Config::get('system', 'proxy_disabled')) {
return $url;
}
// Image URL may have encoded ampersands for display which aren't desirable for proxy
$url = html_entity_decode($url, ENT_NOQUOTES, 'utf-8');
// Creating a sub directory to reduce the amount of files in the cache directory
$basepath = $a->getBasePath() . '/proxy';
$shortpath = hash('md5', $url);
$longpath = substr($shortpath, 0, 2);
if (is_dir($basepath) && $writemode && !is_dir($basepath . '/' . $longpath)) {
mkdir($basepath . '/' . $longpath);
chmod($basepath . '/' . $longpath, 0777);
}
$longpath .= '/' . strtr(base64_encode($url), '+/', '-_');
// Extract the URL extension
$extension = pathinfo(parse_url($url, PHP_URL_PATH), PATHINFO_EXTENSION);
if (in_array($extension, self::$extensions)) {
$shortpath .= '.' . $extension;
$longpath .= '.' . $extension;
}
$proxypath = DI::baseUrl() . '/proxy/' . $longpath;
if ($size != '') {
$size = ':' . $size;
}
// Too long files aren't supported by Apache
// Writemode in combination with long files shouldn't be possible
if ((strlen($proxypath) > 250) && $writemode) {
return $shortpath;
} elseif (strlen($proxypath) > 250) {
return DI::baseUrl() . '/proxy/' . $shortpath . '?url=' . urlencode($url);
} elseif ($writemode) {
return $longpath;
} else {
return $proxypath . $size;
}
}
/**
* @brief "Proxifies" HTML code's image tags
*
* "Proxifies", means replaces image URLs in given HTML code with those from
* proxy storage directory.
*
* @param string $html Un-proxified HTML code
*
* @return string Proxified HTML code
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
public static function proxifyHtml($html)
{
$html = str_replace(Strings::normaliseLink(DI::baseUrl()) . '/', DI::baseUrl() . '/', $html);
return preg_replace_callback('/(<img [^>]*src *= *["\'])([^"\']+)(["\'][^>]*>)/siU', 'self::replaceUrl', $html);
}
/**
* @brief Checks if the URL is a local URL.
*
* @param string $url
* @return boolean
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
private static function isLocalImage($url)
{
if (substr($url, 0, 1) == '/') {
return true;
}
if (strtolower(substr($url, 0, 5)) == 'data:') {
return true;
}
// links normalised - bug #431
$baseurl = Strings::normaliseLink(DI::baseUrl());
$url = Strings::normaliseLink($url);
return (substr($url, 0, strlen($baseurl)) == $baseurl);
}
/**
* @brief Return the array of query string parameters from a URL
*
* @param string $url URL to parse
* @return array Associative array of query string parameters
*/
private static function parseQuery($url)
{
$query = parse_url($url, PHP_URL_QUERY);
$query = html_entity_decode($query);
parse_str($query, $arr);
return $arr;
}
/**
* @brief Call-back method to replace the UR
*
* @param array $matches Matches from preg_replace_callback()
* @return string Proxified HTML image tag
* @throws \Friendica\Network\HTTPException\InternalServerErrorException
*/
private static function replaceUrl(array $matches)
{
// if the picture seems to be from another picture cache then take the original source
$queryvar = self::parseQuery($matches[2]);
if (!empty($queryvar['url']) && substr($queryvar['url'], 0, 4) == 'http') {
$matches[2] = urldecode($queryvar['url']);
}
// Following line changed per bug #431
if (self::isLocalImage($matches[2])) {
return $matches[1] . $matches[2] . $matches[3];
}
// Return proxified HTML
return $matches[1] . self::proxifyUrl(htmlspecialchars_decode($matches[2])) . $matches[3];
}
}