public function discover($url)
{
if (empty($url)) {
throw new Exception('No identity supplied.');
}
$result = ['url' => null, 'version' => null, 'identity' => $url, 'identifier_select' => false, 'ax' => false, 'sreg' => false];
// Use xri.net proxy to resolve i-name identities
if (!preg_match('#^https?:#', $url)) {
$url = 'https://xri.net/' . $url;
}
/* We save the original url in case of Yadis discovery failure.
It can happen when we'll be lead to an XRDS document
which does not have any OpenID2 services.*/
$originalUrl = $url;
// A flag to disable yadis discovery in case of failure in headers.
$yadis = true;
// We'll jump a maximum of 5 times, to avoid endless redirections.
for ($i = 0; $i < 5; $i++) {
if ($yadis) {
$headers = $this->sendRequest($url, 'HEAD');
$next = false;
if (isset($headers['x-xrds-location'])) {
$url = $this->buildUrl($url, trim($headers['x-xrds-location']));
$next = true;
}
if (isset($headers['content-type']) && (strpos($headers['content-type'], 'application/xrds+xml') !== false || strpos($headers['content-type'], 'text/xml') !== false)) {
/* Apparently, some providers return XRDS documents as text/html.
While it is against the spec, allowing this here shouldn't break
compatibility with anything.
---
Found an XRDS document, now let's find the server, and optionally delegate.*/
$content = $this->sendRequest($url, 'GET');
preg_match_all('#<Service.*?>(.*?)</Service>#s', $content, $m);
foreach ($m[1] as $content) {
$content = ' ' . $content;
// The space is added, so that strpos doesn't return 0.
// OpenID 2
$ns = preg_quote('http://specs.openid.net/auth/2.0/');
if (preg_match('#<Type>\\s*' . $ns . '(server|signon)\\s*</Type>#s', $content, $type)) {
if ($type[1] == 'server') {
$result['identifier_select'] = true;
}
preg_match('#<URI.*?>(.*)</URI>#', $content, $server);
preg_match('#<(Local|Canonical)ID>(.*)</\\1ID>#', $content, $delegate);
if (empty($server)) {
throw new Exception('No servers found!');
}
// Does the server advertise support for either AX or SREG?
$result['ax'] = (bool) strpos($content, '<Type>http://openid.net/srv/ax/1.0</Type>');
$result['sreg'] = strpos($content, '<Type>http://openid.net/sreg/1.0</Type>') || strpos($content, '<Type>http://openid.net/extensions/sreg/1.1</Type>');
$server = $server[1];
if (isset($delegate[2])) {
$result['identity'] = trim($delegate[2]);
}
$result['url'] = $server;
$result['version'] = 2;
return $result;
}
// OpenID 1.1
$ns = preg_quote('http://openid.net/signon/1.1');
if (preg_match('#<Type>\\s*' . $ns . '\\s*</Type>#s', $content)) {
preg_match('#<URI.*?>(.*)</URI>#', $content, $server);
preg_match('#<.*?Delegate>(.*)</.*?Delegate>#', $content, $delegate);
if (empty($server)) {
throw new Exception('No servers found!');
}
// AX can be used only with OpenID 2.0, so checking only SREG
$result['sreg'] = strpos($content, '<Type>http://openid.net/sreg/1.0</Type>') || strpos($content, '<Type>http://openid.net/extensions/sreg/1.1</Type>');
$server = $server[1];
if (isset($delegate[1])) {
$result['identity'] = $delegate[1];
}
$result['url'] = $server;
$result['version'] = 1;
return $result;
}
}
$next = true;
$yadis = false;
$url = $originalUrl;
$content = null;
break;
}
if ($next) {
continue;
}
// There are no relevant information in headers, so we search the body.
$content = $this->sendRequest($url, 'GET');
$location = $this->extractHtmlTagValue($content, 'meta', 'http-equiv', 'X-XRDS-Location', 'content');
if ($location) {
$url = $this->buildUrl($url, $location);
continue;
}
}
if (!isset($content)) {
$content = $this->sendRequest($url, 'GET');
}
// At this point, the YADIS Discovery has failed, so we'll switch to openid2 HTML discovery, then fallback to openid 1.1 discovery.
$server = $this->extractHtmlTagValue($content, 'link', 'rel', 'openid2.provider', 'href');
if (!$server) {
// The same with openid 1.1
$server = $this->extractHtmlTagValue($content, 'link', 'rel', 'openid.server', 'href');
$delegate = $this->extractHtmlTagValue($content, 'link', 'rel', 'openid.delegate', 'href');
$version = 1;
} else {
$delegate = $this->extractHtmlTagValue($content, 'link', 'rel', 'openid2.local_id', 'href');
$version = 2;
}
if ($server) {
// We found an OpenID2 OP Endpoint
if ($delegate) {
// We have also found an OP-Local ID.
$result['identity'] = $delegate;
}
$result['url'] = $server;
$result['version'] = $version;
return $result;
}
throw new Exception('No servers found!');
}
throw new Exception('Endless redirection!');
}
