<?php
/**
* This class provides a simple interface for OpenID (1.1 and 2.0) authentication.
* Supports Yadis discovery.
* The authentication process is stateless/dumb.
*
* Usage:
* Sign-on with OpenID is a two step process:
* Step one is authentication with the provider:
* <code>
* $openid = new LightOpenID;
* $openid->identity = 'ID supplied by user';
* header('Location: ' . $openid->authUrl());
* </code>
* The provider then sends various parameters via GET, one of them is openid_mode.
* Step two is verification:
* <code>
* if ($this->data['openid_mode']) {
* $openid = new LightOpenID;
* echo $openid->validate() ? 'Logged in.' : 'Failed';
* }
* </code>
*
* Optionally, you can set $returnUrl and $realm (or $trustRoot, which is an alias).
* The default values for those are:
* $openid->realm = (!empty($_SERVER['HTTPS']) ? 'https' : 'http') . '://' . $_SERVER['HTTP_HOST'];
* $openid->returnUrl = $openid->realm . $_SERVER['REQUEST_URI']; # without the query part, if present
* If you don't know their meaning, refer to any openid tutorial, or specification. Or just guess.
*
* AX and SREG extensions are supported.
* To use them, specify $openid->required and/or $openid->optional before calling $openid->authUrl().
* These are arrays, with values being AX schema paths (the 'path' part of the URL).
* For example:
* $openid->required = array('namePerson/friendly', 'contact/email');
* $openid->optional = array('namePerson/first');
* If the server supports only SREG or OpenID 1.1, these are automaticaly
* mapped to SREG names, so that user doesn't have to know anything about the server.
*
* To get the values, use $openid->getAttributes().
*
*
* The library requires PHP >= 5.1.2 with curl or http/https stream wrappers enabled..
* @author Mewp
* @copyright Copyright (c) 2010, Mewp
* @license http://www.opensource.org/licenses/mit-license.php MIT
*/
class LightOpenID
{
public $returnUrl
, $required = array()
, $optional = array()
, $verify_perr = null
, $capath = null;
private $identity, $claimed_id;
protected $server, $version, $trustRoot, $aliases, $identifier_select = false
, $ax = false, $sreg = false, $data;
static protected $ax_to_sreg = array(
'namePerson/friendly' => 'nickname',
'contact/email' => 'email',
'namePerson' => 'fullname',
'birthDate' => 'dob',
'person/gender' => 'gender',
'contact/postalCode/home' => 'postcode',
'contact/country/home' => 'country',
'pref/language' => 'language',
'pref/timezone' => 'timezone',
);
function __construct()
{
$this->trustRoot = (!empty($_SERVER['HTTPS']) ? 'https' : 'http') . '://' . $_SERVER['HTTP_HOST'];
$uri = $_SERVER['REQUEST_URI'];
$uri = strpos($uri, '?') ? substr($uri, 0, strpos($uri, '?')) : $uri;
$this->returnUrl = $this->trustRoot . $uri;
$this->data = $_POST + $_GET; # OPs may send data as POST or GET.
}
function __set($name, $value)
{
switch ($name) {
case 'identity':
if (strlen($value = trim((String) $value))) {
if (preg_match('#^xri:/*#i', $value, $m)) {
$value = substr($value, strlen($m[0]));
} elseif (!preg_match('/^(?:[=@+\$!\(]|https?:)/i', $value)) {
$value = "http://$value";
}
if (preg_match('#^https?://[^/]+$#i', $value, $m)) {
$value .= '/';
}
}
$this->$name = $this->claimed_id = $value;
break;
case 'trustRoot':
case 'realm':
$this->trustRoot = trim($value);
}
}
function __get($name)
{
switch ($name) {
case 'identity':
# We return claimed_id instead of identity,
# because the developer should see the claimed identifier,
# i.e. what he set as identity, not the op-local identifier (which is what we verify)
return $this->claimed_id;
case 'trustRoot':
case 'realm':
return $this->trustRoot;
}
}
/**
* Checks if the server specified in the url exists.
*
* @param $url url to check
* @return true, if the server exists; false otherwise
*/
function hostExists($url)
{
if (strpos($url, '/') === false) {
$server = $url;
} else {
$server = @parse_url($url, PHP_URL_HOST);
}
if (!$server) {
return false;
}
return !!gethostbynamel($server);
}
protected function request_curl($url, $method='GET', $params=array())
{
$params = http_build_query($params, '', '&');
$curl = curl_init($url . ($method == 'GET' && $params ? '?' . $params : ''));
curl_setopt($curl, CURLOPT_FOLLOWLOCATION, true);
curl_setopt($curl, CURLOPT_HEADER, false);
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, false);
curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);
curl_setopt($curl, CURLOPT_HTTPHEADER, array('Accept: application/xrds+xml, */*'));
if($this->verify_perr !== null) {
curl_setopt($curl, CURLOPT_SSL_VERIFYPEER, $this->verify_peer);
if($this->capath) {
curl_setopt($curl, CURLOPT_CAPATH, $this->capath);
}
}
if ($method == 'POST') {
curl_setopt($curl, CURLOPT_POST, true);
curl_setopt($curl, CURLOPT_POSTFIELDS, $params);
} elseif ($method == 'HEAD') {
curl_setopt($curl, CURLOPT_HEADER, true);
curl_setopt($curl, CURLOPT_NOBODY, true);
} else {
curl_setopt($curl, CURLOPT_HTTPGET, true);
}
$response = curl_exec($curl);
if($method == 'HEAD') {
$headers = array();
foreach(explode("\n", $response) as $header) {
$pos = strpos($header,':');
$name = strtolower(trim(substr($header, 0, $pos)));
$headers[$name] = trim(substr($header, $pos+1));
}
# Updating claimed_id in case of redirections.
$effective_url = curl_getinfo($curl, CURLINFO_EFFECTIVE_URL);
if($effective_url != $url) {
$this->identity = $this->claimed_id = $effective_url;
}
return $headers;
}
if (curl_errno($curl)) {
throw new ErrorException(curl_error($curl), curl_errno($curl));
}
return $response;
}
protected function request_streams($url, $method='GET', $params=array())
{
if(!$this->hostExists($url)) {
throw new ErrorException('Invalid request.');
}
$params = http_build_query($params, '', '&');
switch($method) {
case 'GET':
$opts = array(
'http' => array(
'method' => 'GET',
'header' => 'Accept: application/xrds+xml, */*',
'ignore_errors' => true,
)
);
$url = $url . ($params ? '?' . $params : '');
break;
case 'POST':
$opts = array(
'http' => array(
'method' => 'POST',
'header' => 'Content-type: application/x-www-form-urlencoded',
'content' => $params,
'ignore_errors' => true,
)
);
break;
case 'HEAD':
# We want to send a HEAD request,
# but since get_headers doesn't accept $context parameter,
# we have to change the defaults.
$default = stream_context_get_options(stream_context_get_default());
stream_context_get_default(
array('http' => array(
'method' => 'HEAD',
'header' => 'Accept: application/xrds+xml, */*',
'ignore_errors' => true,
))
);
$url = $url . ($params ? '?' . $params : '');
$headers_tmp = get_headers ($url);
if(!$headers_tmp) {
return array();
}
# Parsing headers.
$headers = array();
foreach($headers_tmp as $header) {
$pos = strpos($header,':');
$name = strtolower(trim(substr($header, 0, $pos)));
$headers[$name] = trim(substr($header, $pos+1));
# Following possible redirections. The point is just to have
# claimed_id change with them, because get_headers() will
# follow redirections automatically.
# We ignore redirections with relative paths.
# If any known provider uses them, file a bug report.
if($name == 'location') {
if(strpos($headers[$name], 'http') === 0) {
$this->identity = $this->claimed_id = $headers[$name];
} elseif($headers[$name][0] == '/') {
$parsed_url = parse_url($this->claimed_id);
$this->identity =
$this->claimed_id = $parsed_url['scheme'] . '://'
. $parsed_url['host']
. $headers[$name];
}
}
}
# And restore them.
stream_context_get_default($default);
return $headers;
}
if($this->verify_peer) {
$opts += array('ssl' => array(
'verify_peer' => true,
'capath' => $this->capath,
));
}
$context = stream_context_create ($opts);
return file_get_contents($url, false, $context);
}
protected function request($url, $method='GET', $params=array())
{
if(function_exists('curl_init') && !ini_get('safe_mode')) {
return $this->request_curl($url, $method, $params);
}
return $this->request_streams($url, $method, $params);
}
protected function build_url($url, $parts)
{
if (isset($url['query'], $parts['query'])) {
$parts['query'] = $url['query'] . '&' . $parts['query'];
}
$url = $parts + $url;
$url = $url['scheme'] . '://'
. (empty($url['username'])?''
:(empty($url['password'])? "{$url['username']}@"
:"{$url['username']}:{$url['password']}@"))
. $url['host']
. (empty($url['port'])?'':":{$url['port']}")
. (empty($url['path'])?'':$url['path'])
. (empty($url['query'])?'':"?{$url['query']}")
. (empty($url['fragment'])?'':":{$url['fragment']}");
return $url;
}
/**
* Helper function used to scan for <meta>/<link> tags and extract information
* from them
*/
protected function htmlTag($content, $tag, $attrName, $attrValue, $valueName)
{
preg_match_all("#<{$tag}[^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*$valueName=['\"](.+?)['\"][^>]*/?>#i", $content, $matches1);
preg_match_all("#<{$tag}[^>]*$valueName=['\"](.+?)['\"][^>]*$attrName=['\"].*?$attrValue.*?['\"][^>]*/?>#i", $content, $matches2);
$result = array_merge($matches1[1], $matches2[1]);
return empty($result)?false:$result[0];
}
/**
* Performs Yadis and HTML discovery. Normally not used.
* @param $url Identity URL.
* @return String OP Endpoint (i.e. OpenID provider address).
* @throws ErrorException
*/
function discover($url)
{
if (!$url) throw new ErrorException('No identity supplied.');
# 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 = $this->request($url, 'HEAD');
$next = false;
if (isset($headers['x-xrds-location'])) {
$url = $this->build_url(parse_url($url), parse_url(trim($headers['x-xrds-location'])));
$next = true;
}
if (isset($headers['content-type'])
&& strpos($headers['content-type'], 'application/xrds+xml') !== false
) {
# Found an XRDS document, now let's find the server, and optionally delegate.
$content = $this->request($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') $this->identifier_select = true;
preg_match('#<URI.*?>(.*)</URI>#', $content, $server);
preg_match('#<(Local|Canonical)ID>(.*)</\1ID>#', $content, $delegate);
if (empty($server)) {
return false;
}
# Does the server advertise support for either AX or SREG?
$this->ax = (bool) strpos($content, '<Type>http://openid.net/srv/ax/1.0</Type>');
$this->sreg = strpos($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])) $this->identity = trim($delegate[2]);
$this->version = 2;
$this->server = $server;
return $server;
}
# 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)) {
return false;
}
# AX can be used only with OpenID 2.0, so checking only SREG
$this->sreg = strpos($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])) $this->identity = $delegate[1];
$this->version = 1;
$this->server = $server;
return $server;
}
}
$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 = $this->request($url, 'GET');
if ($location = $this->htmlTag($content, 'meta', 'http-equiv', 'X-XRDS-Location', 'content')) {
$url = $this->build_url(parse_url($url), parse_url($location));
continue;
}
}
if (!$content) $content = $this->request($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 = $this->htmlTag($content, 'link', 'rel', 'openid2.provider', 'href');
$delegate = $this->htmlTag($content, 'link', 'rel', 'openid2.local_id', 'href');
$this->version = 2;
if (!$server) {
# The same with openid 1.1
$server = $this->htmlTag($content, 'link', 'rel', 'openid.server', 'href');
$delegate = $this->htmlTag($content, 'link', 'rel', 'openid.delegate', 'href');
$this->version = 1;
}
if ($server) {
# We found an OpenID2 OP Endpoint
if ($delegate) {
# We have also found an OP-Local ID.
$this->identity = $delegate;
}
$this->server = $server;
return $server;
}
throw new ErrorException('No servers found!');
}
throw new ErrorException('Endless redirection!');
}
protected function sregParams()
{
$params = array();
# We always use SREG 1.1, even if the server is advertising only support for 1.0.
# That's because it's fully backwards compatibile with 1.0, and some providers
# advertise 1.0 even if they accept only 1.1. One such provider is myopenid.com
$params['openid.ns.sreg'] = 'http://openid.net/extensions/sreg/1.1';
if ($this->required) {
$params['openid.sreg.required'] = array();
foreach ($this->required as $required) {
if (!isset(self::$ax_to_sreg[$required])) continue;
$params['openid.sreg.required'][] = self::$ax_to_sreg[$required];
}
$params['openid.sreg.required'] = implode(',', $params['openid.sreg.required']);
}
if ($this->optional) {
$params['openid.sreg.optional'] = array();
foreach ($this->optional as $optional) {
if (!isset(self::$ax_to_sreg[$optional])) continue;
$params['openid.sreg.optional'][] = self::$ax_to_sreg[$optional];
}
$params['openid.sreg.optional'] = implode(',', $params['openid.sreg.optional']);
}
return $params;
}
protected function axParams()
{
$params = array();
if ($this->required || $this->optional) {
$params['openid.ns.ax'] = 'http://openid.net/srv/ax/1.0';
$params['openid.ax.mode'] = 'fetch_request';
$this->aliases = array();
$counts = array();
$required = array();
$optional = array();
foreach (array('required','optional') as $type) {
foreach ($this->$type as $alias => $field) {
if (is_int($alias)) $alias = strtr($field, '/', '_');
$this->aliases[$alias] = 'http://axschema.org/' . $field;
if (empty($counts[$alias])) $counts[$alias] = 0;
$counts[$alias] += 1;
${$type}[] = $alias;
}
}
foreach ($this->aliases as $alias => $ns) {
$params['openid.ax.type.' . $alias] = $ns;
}
foreach ($counts as $alias => $count) {
if ($count == 1) continue;
$params['openid.ax.count.' . $alias] = $count;
}
# Don't send empty ax.requied and ax.if_available.
# Google and possibly other providers refuse to support ax when one of these is empty.
if($required) {
$params['openid.ax.required'] = implode(',', $required);
}
if($optional) {
$params['openid.ax.if_available'] = implode(',', $optional);
}
}
return $params;
}
protected function authUrl_v1()
{
$returnUrl = $this->returnUrl;
# If we have an openid.delegate that is different from our claimed id,
# we need to somehow preserve the claimed id between requests.
# The simplest way is to just send it along with the return_to url.
if($this->identity != $this->claimed_id) {
$returnUrl .= (strpos($returnUrl, '?') ? '&' : '?') . 'openid.claimed_id=' . $this->claimed_id;
}
$params = array(
'openid.return_to' => $returnUrl,
'openid.mode' => 'checkid_setup',
'openid.identity' => $this->identity,
'openid.trust_root' => $this->trustRoot,
) + $this->sregParams();
return $this->build_url(parse_url($this->server)
, array('query' => http_build_query($params, '', '&')));
}
protected function authUrl_v2($identifier_select)
{
$params = array(
'openid.ns' => 'http://specs.openid.net/auth/2.0',
'openid.mode' => 'checkid_setup',
'openid.return_to' => $this->returnUrl,
'openid.realm' => $this->trustRoot,
);
if ($this->ax) {
$params += $this->axParams();
}
if ($this->sreg) {
$params += $this->sregParams();
}
if (!$this->ax && !$this->sreg) {
# If OP doesn't advertise either SREG, nor AX, let's send them both
# in worst case we don't get anything in return.
$params += $this->axParams() + $this->sregParams();
}
if ($identifier_select) {
$params['openid.identity'] = $params['openid.claimed_id']
= 'http://specs.openid.net/auth/2.0/identifier_select';
} else {
$params['openid.identity'] = $this->identity;
$params['openid.claimed_id'] = $this->claimed_id;
}
return $this->build_url(parse_url($this->server)
, array('query' => http_build_query($params, '', '&')));
}
/**
* Returns authentication url. Usually, you want to redirect your user to it.
* @return String The authentication url.
* @param String $select_identifier Whether to request OP to select identity for an user in OpenID 2. Does not affect OpenID 1.
* @throws ErrorException
*/
function authUrl($identifier_select = null)
{
if (!$this->server) $this->discover($this->identity);
if ($this->version == 2) {
if ($identifier_select === null) {
return $this->authUrl_v2($this->identifier_select);
}
return $this->authUrl_v2($identifier_select);
}
return $this->authUrl_v1();
}
/**
* Performs OpenID verification with the OP.
* @return Bool Whether the verification was successful.
* @throws ErrorException
*/
function validate()
{
$this->claimed_id = isset($this->data['openid_claimed_id'])?$this->data['openid_claimed_id']:$this->data['openid_identity'];
$params = array(
'openid.assoc_handle' => $this->data['openid_assoc_handle'],
'openid.signed' => $this->data['openid_signed'],
'openid.sig' => $this->data['openid_sig'],
);
if (isset($this->data['openid_ns'])) {
# We're dealing with an OpenID 2.0 server, so let's set an ns
# Even though we should know location of the endpoint,
# we still need to verify it by discovery, so $server is not set here
$params['openid.ns'] = 'http://specs.openid.net/auth/2.0';
} elseif(isset($this->data['openid_claimed_id'])) {
# If it's an OpenID 1 provider, and we've got claimed_id,
# we have to append it to the returnUrl, like authUrl_v1 does.
$this->returnUrl .= (strpos($this->returnUrl, '?') ? '&' : '?')
. 'openid.claimed_id=' . $this->claimed_id;
}
if ($this->data['openid_return_to'] != $this->returnUrl) {
# The return_to url must match the url of current request.
# I'm assuing that noone will set the returnUrl to something that doesn't make sense.
return false;
}
$server = $this->discover($this->claimed_id);
foreach (explode(',', $this->data['openid_signed']) as $item) {
# Checking whether magic_quotes_gpc is turned on, because
# the function may fail if it is. For example, when fetching
# AX namePerson, it might containg an apostrophe, which will be escaped.
# In such case, validation would fail, since we'd send different data than OP
# wants to verify. stripslashes() should solve that problem, but we can't
# use it when magic_quotes is off.
$value = $this->data['openid_' . str_replace('.','_',$item)];
$params['openid.' . $item] = get_magic_quotes_gpc() ? stripslashes($value) : $value;
}
$params['openid.mode'] = 'check_authentication';
$response = $this->request($server, 'POST', $params);
return preg_match('/is_valid\s*:\s*true/i', $response);
}
protected function getAxAttributes()
{
$alias = null;
if (isset($this->data['openid_ns_ax'])
&& $this->data['openid_ns_ax'] != 'http://openid.net/srv/ax/1.0'
) { # It's the most likely case, so we'll check it before
$alias = 'ax';
} else {
# 'ax' prefix is either undefined, or points to another extension,
# so we search for another prefix
foreach ($this->data as $key => $val) {
if (substr($key, 0, strlen('openid_ns_')) == 'openid_ns_'
&& $val == 'http://openid.net/srv/ax/1.0'
) {
$alias = substr($key, strlen('openid_ns_'));
break;
}
}
}
if (!$alias) {
# An alias for AX schema has not been found,
# so there is no AX data in the OP's response
return array();
}
$attributes = array();
foreach ($this->data as $key => $value) {
$keyMatch = 'openid_' . $alias . '_value_';
if (substr($key, 0, strlen($keyMatch)) != $keyMatch) {
continue;
}
$key = substr($key, strlen($keyMatch));
if (!isset($this->data['openid_' . $alias . '_type_' . $key])) {
# OP is breaking the spec by returning a field without
# associated ns. This shouldn't happen, but it's better
# to check, than cause an E_NOTICE.
continue;
}
$key = substr($this->data['openid_' . $alias . '_type_' . $key],
strlen('http://axschema.org/'));
$attributes[$key] = $value;
}
return $attributes;
}
protected function getSregAttributes()
{
$attributes = array();
$sreg_to_ax = array_flip(self::$ax_to_sreg);
foreach ($this->data as $key => $value) {
$keyMatch = 'openid_sreg_';
if (substr($key, 0, strlen($keyMatch)) != $keyMatch) {
continue;
}
$key = substr($key, strlen($keyMatch));
if (!isset($sreg_to_ax[$key])) {
# The field name isn't part of the SREG spec, so we ignore it.
continue;
}
$attributes[$sreg_to_ax[$key]] = $value;
}
return $attributes;
}
/**
* Gets AX/SREG attributes provided by OP. should be used only after successful validaton.
* Note that it does not guarantee that any of the required/optional parameters will be present,
* or that there will be no other attributes besides those specified.
* In other words. OP may provide whatever information it wants to.
* * SREG names will be mapped to AX names.
* * @return Array Array of attributes with keys being the AX schema names, e.g. 'contact/email'
* @see http://www.axschema.org/types/
*/
function getAttributes()
{
if (isset($this->data['openid_ns'])
&& $this->data['openid_ns'] == 'http://specs.openid.net/auth/2.0'
) { # OpenID 2.0
# We search for both AX and SREG attributes, with AX taking precedence.
return $this->getAxAttributes() + $this->getSregAttributes();
}
return $this->getSregAttributes();
}
}
