/www/discovery.inc.php
PHP | 647 lines | 258 code | 73 blank | 316 comment | 84 complexity | 255530454f12113d590edec49b215426 MD5 | raw file
- <?php
- /*
- * SimpleID
- *
- * Copyright (C) Kelvin Mo 2007-9
- *
- * This program is free software; you can redistribute it and/or
- * modify it under the terms of the GNU General Public
- * License as published by the Free Software Foundation; either
- * version 2 of the License, or (at your option) any later version.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
- * General Public License for more details.
- *
- * You should have received a copy of the GNU General Public
- * License along with this program; if not, write to the Free
- * Software Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
- *
- * $Id$
- */
- /**
- * Support for XRDS based discovery.
- *
- * The functions for this file supports HTTP-based identifiers. For XRIs, the
- * resolution service xri.net is used to resolve to HTTP-based URLs.
- *
- * @package simpleid
- * @since 0.7
- * @filesource
- */
-
- include_once "http.inc.php";
- /**
- * The namespace identifier for an XRDS document.
- */
- define('XRDS_NS', 'xri://$xrds');
- /**
- * The namespace identifier for XRDS version 2.
- */
- define('XRD2_NS', 'xri://$xrd*($v*2.0)');
- /**
- * The namespace identifier for XRDS Simple.
- */
- define('XRDS_SIMPLE_NS', 'http://xrds-simple.net/core/1.0');
- /**
- * The type identifier for XRDS Simple.
- */
- define('XRDS_SIMPLE_TYPE', 'xri://$xrds*simple');
- /**
- * The namespace identifier for OpenID services.
- */
- define('XRD_OPENID_NS', 'http://openid.net/xmlns/1.0');
- /**
- * Obtains the services for particular identifier.
- *
- * This function attempts to discover and obtain the XRDS document associated
- * with the identifier, parses the XRDS document and returns an array of
- * services.
- *
- * If an XRDS document is not found, and $openid is set to true, this function
- * will also attempt to discover OpenID services by looking for link elements
- * with rel of openid.server or openid2.provider in the discovered HTML document.
- *
- * @param string $identifier the identifier
- * @param bool $openid if true, performs additional discovery of OpenID services
- * by looking for link elements within the discovered document
- * @return array an array of discovered services, or an empty array if no services
- * are found
- */
- function discovery_xrds_discover($identifier, $openid = FALSE) {
- $identifier = discovery_xrds_normalize($identifier);
- $url = discovery_xrds_url($identifier);
-
- $xrds = discovery_xrds_get($url);
- if ($xrds) {
- return discovery_xrds_parse($xrds);
- } else {
- if ($openid) return discovery_html_get_services($url);
- return array();
- }
- }
- /**
- * Given an array of discovered services, obtains information on services of
- * a particular type.
- *
- * @param array $services the discovered services
- * @param string $type the URI of the type of service to obtain
- * @return array an array of matching services, or an empty array of no services
- * match
- */
- function discovery_xrds_services_by_type($services, $type) {
- $matches = array();
-
- foreach ($services as $service) {
- foreach ($service['type'] as $service_type) {
- if ($service_type == $type) $matches[] = $service;
- }
- }
- return $matches;
- }
- /**
- * Given an array of discovered services, obtains information on the service of
- * a specified ID.
- *
- * @param array $services the discovered services
- * @param string $id the XML ID of the service in the XRDS document
- * @return array the matching service, or NULL of no services
- * are found
- */
- function discovery_xrds_service_by_id($services, $id) {
- foreach ($services as $service) {
- if ($service['#id'] == $id) return $service;
- }
- return NULL;
- }
- /**
- * Obtains a XRDS document at a particular URL. Performs Yadis discovery if
- * the URL does not produce a XRDS document.
- *
- * @param string $url the URL
- * @param bool $check whether to check the content type of the response is
- * application/xrds+xml
- * @param int $retries the number of tries to make
- * @return string the contents of the XRDS document
- */
- function discovery_xrds_get($url, $check = TRUE, $retries = 5) {
- if ($retries == 0) return NULL;
-
- $response = http_make_request($url, array('Accept' => 'application/xrds+xml'));
- if (isset($response['http-error'])) return NULL;
- if (($response['content-type'] == 'application/xrds+xml') || ($check == FALSE)) {
- return $response['data'];
- } elseif (isset($response['headers']['x-xrds-location'])) {
- return discovery_xrds_get($response['headers']['x-xrds-location'], false, $retries - 1);
- } else {
- $location = _discovery_meta_httpequiv('X-XRDS-Location', $response['data']);
- if ($location) {
- return discovery_xrds_get($location, false, $retries - 1);
- }
- return NULL;
- }
- }
- /**
- * Normalises an identifier for discovery.
- *
- * If the identifier begins with xri://, acct: or mailto:, this is stripped out. If the identifier
- * does not begin with a valid URI scheme, http:// is assumed and added to the
- * identifier.
- *
- * @param string $identifier the identifier to normalise
- * @return string the normalised identifier
- */
- function discovery_xrds_normalize($identifier) {
- $normalized = $identifier;
-
- if (discovery_is_xri($identifier)) {
- if (stristr($identifier, 'xri://') !== false) $normalized = substr($identifier, 6);
- } elseif (discovery_is_email($identifier)) {
- if (stristr($identifier, 'acct:') !== false) $normalized = substr($identifier, 5);
- if (stristr($identifier, 'mailto:') !== false) $normalized = substr($identifier, 7);
- } else {
- if (stristr($identifier, '://') === false) $normalized = 'http://'. $identifier;
- if (substr_count($normalized, '/') < 3) $normalized .= '/';
- }
-
- return $normalized;
- }
- /**
- * Obtains a URL for an identifier. If the identifier is a XRI, the XRI resolution
- * service is used to convert the identifier to a URL.
- *
- * @param string $identifier the identifier
- * @return string the URL
- */
- function discovery_xrds_url($identifier) {
- if (discovery_is_xri($identifier)) {
- return 'http://xri.net/' . $identifier;
- } elseif (discovery_is_email($identifier)) {
- //list($user, $host) = explode('@', $identifier, 2);
- //$host_meta = 'http://' . $host . '/.well-known/host-meta';
- } else {
- return $identifier;
- }
- }
- /**
- * Determines whether an identifier is an XRI.
- *
- * XRI identifiers either start with xri:// or with @, =, +, $ or !.
- *
- * @param string $identifier the parameter to test
- * @return bool true if the identifier is an XRI
- */
- function discovery_is_xri($identifier) {
- $firstchar = substr($identifier, 0, 1);
- if ($firstchar == "@" || $firstchar == "=" || $firstchar == "+" || $firstchar == "\$" || $firstchar == "!") return true;
- if (stristr($identifier, 'xri://') !== FALSE) return true;
- return false;
- }
- /**
- * Determines whether an identifier is an e-mail address.
- *
- * An identifier is an e-mail address if it:
- *
- * - has a single @ character
- * - does not have a slash character
- *
- * @param string $identifier the parameter to test
- * @return bool true if the identifier is an e-mail address
- */
- function discovery_is_email($identifier) {
- // If it begins with acct: or mailto:, strip it out
- if (stristr($identifier, 'acct:') !== false) $identifier = substr($identifier, 5);
- if (stristr($identifier, 'mailto:') !== false) $identifier = substr($identifier, 7);
-
- // If it contains a slash, it is not an e-mail address
- if (strpos($identifier, "/") !== false) return false;
-
- $at = strpos($identifier, "@");
-
- // If it does not contain a @, it is not an e-mail address
- if ($at === false) return false;
-
- // If it contains more than one @, it is not an e-mail
- if (strrpos($identifier, "@") != $at) return false;
-
- return true;
- }
- /**
- * Callback function to sort service and URI elements based on priorities
- * specified in the XRDS document.
- *
- * The XRDS specification allows multiple instances of certain elements, such
- * as Service and URI. The specification allows an attribute called priority
- * so that the document creator can specify the order the elements should be used.
- *
- * @param array $a
- * @param array $b
- * @return int
- */
- function discovery_xrds_priority_sort($a, $b) {
- if (!isset($a['#priority']) && !isset($b['#priority'])) return 0;
-
- // if #priority is missing, #priority is assumed to be infinity
- if (!isset($a['#priority'])) return 1;
- if (!isset($b['#priority'])) return -1;
-
- if ($a['#priority'] == $b['#priority']) return 0;
- return ($a['#priority'] < $b['#priority']) ? -1 : 1;
- }
- /**
- * Parses an XRDS document to return services available.
- *
- * @param string $xrds the XRDS document
- * @return array the parsed structure
- *
- * @see XRDSParser
- */
- function discovery_xrds_parse($xrds) {
- $parser = new XRDSParser();
- $parser->parse($xrds);
- $parser->free();
- $services = $parser->services();
- uasort($services, 'discovery_xrds_priority_sort');
- return $services;
- }
- /**
- * Obtains the OpenID services for particular identifier by scanning for link
- * elements in the returned document.
- *
- * Note that this function does not use the YADIS protocol to scan for services.
- * To use the YADIS protocol, use {@link discovery_get_services()}.
- *
- * @param string $url the URL
- * @return array an array of discovered services, or an empty array if no services
- * are found
- */
- function discovery_html_get_services($url) {
- $services = array();
-
- $response = http_make_request($url);
- $html = $response['data'];
-
- $uri = _discovery_link_rel('openid2.provider', $html);
- $delegate = _discovery_link_rel('openid2.local_id', $html);
-
- if ($uri) {
- $service = array(
- 'type' => 'http://specs.openid.net/auth/2.0/signon',
- 'uri' => $uri
- );
- if ($delegate) $service['localid'] = $delegate;
- $services[] = $service;
- }
- $uri = _discovery_link_rel('openid.server', $html);
- $delegate = _discovery_link_rel('openid.delegate', $html);
-
- if ($uri) {
- $service = array(
- 'type' => 'http://openid.net/signon/1.0',
- 'uri' => $uri
- );
- if ($delegate) $service['localid'] = $delegate;
- $services[] = $service;
- }
-
- return $services;
- }
- /**
- * Searches through an HTML document to obtain the value of a meta
- * element with a specified http-equiv attribute.
- *
- * @param string $equiv the http-equiv attribute for which to search
- * @param string $html the HTML document to search
- * @return mixed the value of the meta element, or FALSE if the element is not
- * found
- */
- function _discovery_meta_httpequiv($equiv, $html) {
- $html = preg_replace('/<!(?:--(?:[^-]*|-[^-]+)*--\s*)>/', '', $html); // Strip html comments
-
- $equiv = preg_quote($equiv);
- preg_match('|<meta\s+http-equiv=["\']'. $equiv .'["\'](.*)/?>|iUs', $html, $matches);
- if (isset($matches[1])) {
- preg_match('|content=["\']([^"]+)["\']|iUs', $matches[1], $content);
- if (isset($content[1])) {
- return $content[1];
- }
- }
- return FALSE;
- }
- /**
- * Searches through an HTML document to obtain the value of a link
- * element with a specified rel attribute.
- *
- * @param string $rel the rel attribute for which to search
- * @param string $html the HTML document to search
- * @return mixed the href of the link element, or FALSE if the element is not
- * found
- */
- function _discovery_link_rel($rel, $html) {
- $html = preg_replace('/<!(?:--(?:[^-]*|-[^-]+)*--\s*)>/s', '', $html); // Strip html comments
-
- $rel = preg_quote($rel);
- preg_match('|<link\s+rel=["\'](.*)'. $rel .'(.*)["\'](.*)/?>|iUs', $html, $matches);
- if (isset($matches[3])) {
- preg_match('|href=["\']([^"]+)["\']|iU', $matches[3], $href);
- return trim($href[1]);
- }
- return FALSE;
- }
- /**
- * A simple XRDS parser.
- *
- * This parser uses the classic expat functions available in PHP to parse the
- * XRDS Simple XML document.
- *
- * The result is an array of discovered services.
- *
- * @link http://xrds-simple.net/
- */
- class XRDSParser {
- /**
- * XML parser
- * @var resource
- * @access private
- */
- var $parser;
-
- /**
- * Discovered services
- * @var array
- * @access private
- */
- var $services = array();
-
- /**
- * State: are we parsing a service element?
- * @var bool
- * @access private
- */
- var $in_service = FALSE;
-
- /**
- * CDATA buffer
- * @var string
- * @access private
- */
- var $_buffer;
- /**
- * Attributes buffer
- * @var array
- * @access private
- */
- var $_attribs = array();
-
- /**
- * priority attribute buffer
- * @var string
- * @access private
- */
- var $priority = NULL;
-
- /**
- * Currently parsed service buffer
- * @var array
- * @access private
- */
- var $service = array();
-
- /**
- * Creates an instance of the XRDS parser.
- *
- * This constructor also initialises the underlying XML parser.
- */
- function XRDSParser() {
- $this->parser = xml_parser_create_ns();
- xml_parser_set_option($this->parser, XML_OPTION_CASE_FOLDING,0);
- xml_set_object($this->parser, $this);
- xml_set_element_handler($this->parser, 'element_start', 'element_end');
- xml_set_character_data_handler($this->parser, 'cdata');
- }
-
- /**
- * Frees memory associated with the underlying XML parser.
- *
- * Note that only the memory associated with the underlying XML parser is
- * freed. Memory associated with the class itself is not freed.
- *
- * @access public
- */
- function free() {
- xml_parser_free($this->parser);
- }
-
- /**
- * Parses an XRDS document.
- *
- * Once the parsing is complete, use {@link XRDSParser::services()} to obtain
- * the services extracted from the document.
- *
- * @param string $xml the XML document to parse
- * @access public
- */
- function parse($xml) {
- xml_parse($this->parser, $xml);
- }
-
- /**
- * Gets an array of discovered services.
- *
- * @return array an array of discovered services, or an empty array
- * @access public
- * @see XRDSParser::parse()
- */
- function services() {
- return $this->services;
- }
-
- /**
- * XML parser callback
- *
- * @access private
- */
- function element_start(&$parser, $qualified, $attribs) {
- list($ns, $name) = $this->parse_namespace($qualified);
- // Strictly speaking, XML namespace URIs are semi-case sensitive
- // (i.e. the scheme and host are not case sensitive, but other elements
- // are). However, the XRDS-Simple specifications defines a
- // namespace URI for XRD (xri://$XRD*($v*2.0) rather than xri://$xrd*($v*2.0))
- // with an unusual case.
- if ((strtolower($ns) == strtolower(XRD2_NS)) && ($name == 'Service')) {
- $this->in_service = TRUE;
- $this->service = array();
-
- if (in_array('priority', $attribs)) {
- $this->service['#priority'] = $attribs['priority'];
- }
- if (in_array('id', $attribs)) {
- $this->service['#id'] = $attribs['id'];
- }
- }
-
- if ((strtolower($ns) == strtolower(XRD2_NS)) && ($this->in_service)) {
- switch ($name) {
- case 'Type':
- case 'LocalID':
- case 'URI':
- if (in_array('priority', $attribs)) {
- $this->priority = $attribs['priority'];
- } else {
- $this->priority = NULL;
- }
- }
- }
-
- $this->_buffer = '';
- $this->_attribs = $attribs;
- }
- /**
- * XML parser callback
- *
- * @access private
- */
- function element_end(&$parser, $qualified) {
- list($ns, $name) = $this->parse_namespace($qualified);
-
- if ((strtolower($ns) == strtolower(XRD2_NS)) && ($this->in_service)) {
- switch ($name) {
- case 'Service':
- foreach (array('type', 'localid', 'uri') as $key) {
- if (!isset($this->service[$key])) continue;
- $this->service[$key] = $this->flatten_uris($this->service[$key]);
- }
-
- $this->services[] = $this->service;
- $this->in_service = FALSE;
- break;
- case 'Type':
- case 'LocalID':
- case 'URI':
- $key = strtolower($name);
- if (!isset($this->service[$key])) {
- $this->service[$key] = array();
- }
- if ($this->priority != NULL) {
- $this->service[$key][] = array('#uri' => trim($this->_buffer), '#priority' => $this->priority);
- } else {
- $this->service[$key][] = array('#uri' => trim($this->_buffer));
- }
- $this->priority = NULL;
- break;
- }
- }
-
- if ((strtolower($ns) == strtolower(XRD_OPENID_NS)) && ($this->in_service)) {
- switch ($name) {
- case 'Delegate':
- $this->service['delegate'] = trim($this->_buffer);
- }
- }
- $this->_attribs = array();
- }
- /**
- * XML parser callback
- *
- * @access private
- */
- function cdata(&$parser, $data) {
- $this->_buffer .= $data;
- }
-
- /**
- * Parses a namespace-qualified element name.
- *
- * @param string $qualified the qualified name
- * @return array an array with two elements - the first element contains
- * the namespace qualifier (or an empty string), the second element contains
- * the element name
- * @access protected
- */
- function parse_namespace($qualified) {
- $pos = strrpos($qualified, ':');
- if ($pos !== FALSE) return array(substr($qualified, 0, $pos), substr($qualified, $pos + 1, strlen($qualified)));
- return array('', $qualified);
- }
-
- /**
- * Flattens the service array.
- *
- * In an XRDS document, child elements of the service element often contains
- * a list of URIs, with the priority specified in the priority attribute.
- *
- * When the document is parsed in this class, the URI and the priority are first
- * extracted into the #uri and the #priority keys respectively. This function
- * takes this array, sorts the elements using the #priority keys (if $sort is
- * true), then collapses the array using the value associated with the #uri key.
- *
- * @param array $array the service array, with URIs and priorities
- * @param bool $sort whether to sort the service array using the #priority
- * keys
- * @return array the services array with URIs sorted by priority
- * @access protected
- */
- function flatten_uris($array, $sort = TRUE) {
- $result = array();
-
- if ($sort) uasort($array, 'discovery_xrds_priority_sort');
-
- for ($i = 0; $i < count($array); $i++) {
- $result[] = $array[$i]['#uri'];
- }
-
- return $result;
- }
- }
- if (!function_exists('rfc3986_urlencode')) {
- /**
- * Encodes a URL using RFC 3986.
- *
- * PHP's rawurlencode function encodes a URL using RFC 1738. RFC 1738 has been
- * updated by RFC 3986, which change the list of characters which needs to be
- * encoded.
- *
- * Strictly correct encoding is required for various purposes, such as OAuth
- * signature base strings.
- *
- * @param string $s the URL to encode
- * @return string the encoded URL
- */
- function rfc3986_urlencode($s) {
- return str_replace('%7E', '~', rawurlencode($s));
- }
- }
- ?>