/**
* Get the base domain (without protocol and any subdomain) of an URL.
*
* Gets a max of 3 domain parts (x.y.tld)
*
* @param string URL
* @return string the base domain (may become empty, if found invalid)
*/
function get_base_domain($url)
{
global $evo_charset;
//echo '<p>'.$url;
// Chop away the http part and the path:
$domain = preg_replace('~^([a-z]+://)?([^:/#]+)(.*)$~i', '\\2', $url);
if (empty($domain) || preg_match('~^(\\d+\\.)+\\d+$~', $domain)) {
// Empty or All numeric = IP address, don't try to cut it any further
return $domain;
}
//echo '<br>'.$domain;
// Get the base domain up to 3 levels (x.y.tld):
// NOTE: "_" is not really valid, but for Windows it is..
// NOTE: \w includes "_"
// convert URL to IDN:
$domain = idna_encode($domain);
$domain_pattern = '~ ( \\w (\\w|-|_)* \\. ){0,2} \\w (\\w|-|_)* $~ix';
if (!preg_match($domain_pattern, $domain, $match)) {
return '';
}
$base_domain = convert_charset(idna_decode($match[0]), $evo_charset, 'UTF-8');
// Remove any www. prefix:
$base_domain = preg_replace('~^www\\.~i', '', $base_domain);
//echo '<br>'.$base_domain.'</p>';
return $base_domain;
}
/**
* Check the content of a given URL (referer), if the requested URI (with different hostname variations)
* is present.
*
* @todo Use DB cache to avoid checking the same page again and again! (Plugin DB table)
*
* @param string
* @param string URI to append to matching pattern for hostnames
* @return boolean
*/
function is_referer_linking_us($referer, $uri)
{
global $misc_inc_path, $lib_subdir, $ReqHost;
if (empty($referer)) {
return false;
}
// Load page content (max. 500kb), using fsockopen:
$url_parsed = @parse_url($referer);
if (!$url_parsed) {
return false;
}
if (empty($url_parsed['scheme'])) {
$url_parsed = parse_url('http://' . $referer);
}
$host = $url_parsed['host'];
$port = empty($url_parsed['port']) ? 80 : $url_parsed['port'];
$path = empty($url_parsed['path']) ? '/' : $url_parsed['path'];
if (!empty($url_parsed['query'])) {
$path .= '?' . $url_parsed['query'];
}
$fp = @fsockopen($host, $port, $errno, $errstr, 30);
if (!$fp) {
// could not access referring page
$this->debug_log('is_referer_linking_us(): could not access «' . $referer . '» (host: ' . $host . '): ' . $errstr . ' (#' . $errno . ')');
return false;
}
// Set timeout for data:
if (function_exists('stream_set_timeout')) {
stream_set_timeout($fp, 20);
} else {
socket_set_timeout($fp, 20);
}
// PHP 4
// Send request:
$out = "GET {$path} HTTP/1.0\r\n";
$out .= "Host: {$host}:{$port}\r\n";
$out .= "Connection: Close\r\n\r\n";
fwrite($fp, $out);
// Skip headers:
$i = 0;
$source_charset = 'iso-8859-1';
// default
while (($s = fgets($fp, 4096)) !== false) {
$i++;
if ($s == "\r\n" || $i > 100) {
break;
}
if (preg_match('~^Content-Type:.*?charset=([\\w-]+)~i', $s, $match)) {
$source_charset = $match[1];
}
}
// Get the refering page's content
$content_ref_page = '';
$bytes_read = 0;
while (($s = fgets($fp, 4096)) !== false) {
$content_ref_page .= $s;
$bytes_read += strlen($s);
if ($bytes_read > 512000) {
// do not pull more than 500kb of data!
break;
}
}
fclose($fp);
if (!strlen($content_ref_page)) {
$this->debug_log('is_referer_linking_us(): empty $content_ref_page (' . bytesreadable($bytes_read) . ' read)');
return false;
}
$have_idn_name = false;
// Build the search pattern:
// We match for basically for 'href="[SERVER][URI]', where [SERVER] is a list of possible hosts (especially IDNA)
$search_pattern = '~\\shref=["\']?https?://(';
$possible_hosts = array($_SERVER['HTTP_HOST']);
if ($_SERVER['SERVER_NAME'] != $_SERVER['HTTP_HOST']) {
$possible_hosts[] = $_SERVER['SERVER_NAME'];
}
$search_pattern_hosts = array();
foreach ($possible_hosts as $l_host) {
if (preg_match('~^([^.]+\\.)(.*?)([^.]+\\.[^.]+)$~', $l_host, $match)) {
// we have subdomains in this hostname
if (stristr($match[1], 'www')) {
// search also for hostname without 'www.'
$search_pattern_hosts[] = $match[2] . $match[3];
}
}
$search_pattern_hosts[] = $l_host;
}
$search_pattern_hosts = array_unique($search_pattern_hosts);
foreach ($search_pattern_hosts as $l_host) {
// add IDN, because this could be linked:
$l_idn_host = idna_decode($l_host);
// the decoded puny-code ("xn--..") name (utf8)
if ($l_idn_host != $l_host) {
$have_idn_name = true;
$search_pattern_hosts[] = $l_idn_host;
}
}
// add hosts to pattern, preg_quoted
for ($i = 0, $n = count($search_pattern_hosts); $i < $n; $i++) {
$search_pattern_hosts[$i] = preg_quote($search_pattern_hosts[$i], '~');
}
$search_pattern .= implode('|', $search_pattern_hosts) . ')';
if (empty($uri)) {
// host(s) should end with "/", "'", '"', "?" or whitespace
$search_pattern .= '[/"\'\\s?]';
} else {
$search_pattern .= preg_quote($uri, '~');
// URI should end with "'", '"' or whitespace
$search_pattern .= '["\'\\s]';
}
$search_pattern .= '~i';
if ($have_idn_name) {
// Convert charset to UTF-8, because the decoded domain name is UTF-8, too:
if (can_convert_charsets('utf-8', $source_charset)) {
$content_ref_page = convert_charset($content_ref_page, 'utf-8', $source_charset);
} else {
$this->debug_log('is_referer_linking_us(): warning: cannot convert charset of referring page');
}
}
if (preg_match($search_pattern, $content_ref_page)) {
$this->debug_log('is_referer_linking_us(): found current URL in page (' . bytesreadable($bytes_read) . ' read)');
return true;
} else {
if (strpos($referer, $ReqHost) === 0 && !empty($uri)) {
// Referer is the same host.. just search for $uri
if (strpos($content_ref_page, $uri) !== false) {
$this->debug_log('is_referer_linking_us(): found current URI in page (' . bytesreadable($bytes_read) . ' read)');
return true;
}
}
$this->debug_log('is_referer_linking_us(): ' . sprintf('did not find «%s» in «%s» (%s bytes read).', $search_pattern, $referer, bytesreadable($bytes_read)));
return false;
}
}
