example.php

<?php
header('Content-Type: text/plain');
session_start();

require 'OAuth.php';
require 'OAuthClient.php';

$path_to_this_page = 'http://yourdomain.com/example.php';

$sp = new OAuthServiceProvider(
	'https://api.login.yahoo.com/oauth/v2/get_request_token',
	'https://api.login.yahoo.com/oauth/v2/request_auth',
	'https://api.login.yahoo.com/oauth/v2/get_token'
);

$consumer = new OAuthConsumer(
	'your api key here (not! api id)',
	'your shared secret here'
);

if( isset($_GET['logout']) ) {
	unset($_SESSION['request_token']);
	unset($_SESSION['access_token']);
	header('Location: ' . $path_to_this_page);
	die;
} else if( isset($_SESSION['access_token']) ) {
	$at = unserialize($_SESSION['access_token']);
	$api = new OAuthClient( $sp, $consumer, $at );
	
} else {
	$api = new OAuthClient( $sp, $consumer );
	
	if( isset($_SESSION['request_token']) && isset($_GET['oauth_verifier']) ) {
		$request_token = unserialize($_SESSION['request_token']);
		$verifier_code  = $_GET['oauth_verifier'];
		
		$access_token = $api->getAccessToken( $request_token, $verifier_code );
		$_SESSION['access_token'] = serialize($access_token);
		header('Location: ' . $path_to_this_page );
	} else {
		$request_token = $api->getRequestToken( $path_to_this_page );
		$_SESSION['request_token'] = serialize($request_token);
		
		$request_uri = $api->getAuthorizeUrl( $request_token );
		header('Location: ' . $request_uri );
	}
	die;
}

echo 'Authorized!';


// perform requests

// Fetch GUID of authenticated user
$guid_resp = $api->call('http://social.yahooapis.com/v1/me/guid', array());
$guid_sxml = new SimpleXMLElement($guid_resp);
$guid =	(string) $guid_sxml->value;

// Fetch profile of said user
$profile_json = $api->call('http://social.yahooapis.com/v1/user/' . $guid . '/profile', array('format'=>'json'));
$profile = json_decode($profile_json);

echo 'Your name is: ' . $profile->profile->givenName . ' ' . $profile->profile->familyName . "\n\n";

print_r( $profile );

OAuthClient.php

<?php
 
/**
 * A General purpose client for OAuth APIs
 *
 * @requires OAuth-php (http://oauth.googlecode.com/svn/code/php/) *
 * @copyright OAuth.net (C) 2009
 */
 
/**
 * The exception thrown when something bad happens in CampusNotesAPI
 */
class OAuthClientException extends Exception {}
 
/**
 * A class to identify different service providers
 * @author Morten Fangel <fangel@sevengoslings.net>
 */
class OAuthServiceProvider {
	private $request_token_uri;
	private $authorization_uri;
	private $access_token_uri;
	
	/**
	 * @param string $rt URI of the 'request token' endpoint
	 * @param string $a  URI of the 'authorize request token' endpoint
	 * @param string $at URI of the 'access token' endpoint
	 */
	public function __construct($rt, $a, $at) {
		$this->request_token_uri = $rt;
		$this->authorization_uri = $a;
		$this->access_token_uri  = $at;
	}
	
	public function request_token_uri() { return $this->request_token_uri; }
	public function authorization_uri() { return $this->authorization_uri; }
	public function access_token_uri()  { return $this->access_token_uri; }
}

/**
 * CampusNotesAPI is the main class. It contains methods
 * for getting the relevant tokens, and for querying the
 * API
 * @author Morten Fangel <fangel@sevengoslings.net>
 */
class OAuthClient {
	private $service_provider;
	private $oauth_consumer;
	private $oauth_token;
	private $hmac_signature_method;
  
	/**
	 * Create a new YahooAPI instance
	 * @param OAuthConsumer $c Your consumer info
	 * @param OAuthToken $t Your AccessToken (null if none)
	 */
	public function __construct( OAuthServiceProvider $sp, OAuthConsumer $c, OAuthToken $t = null ) {
		$this->service_provider = $sp;
		$this->oauth_consumer = $c;
		$this->oauth_token = $t;
		$this->hmac_signature_method = $hmac_method = new OAuthSignatureMethod_HMAC_SHA1();
 
	}
 
	/**
	 * Fetches a new RequestToken for you to use..
	 * @throws OAuthClientException
	 * @return OAuthToken
	 */
	public function getRequestToken( $callback = 'oob' ) {
		$req = OAuthRequest::from_consumer_and_token(
			$this->oauth_consumer,
			null,
			'GET',
			$this->service_provider->request_token_uri()
		);
		$req->set_parameter('oauth_callback', $callback);

		$token_str = $this->_performRequest($req);
		parse_str($token_str, $token_arr);
 
		if( isset($token_arr['oauth_token'], $token_arr['oauth_token_secret']) ) {
			return new OAuthToken($token_arr['oauth_token'], $token_arr['oauth_token_secret']);
		} else {
			return null;
		}
	}
 
	/**
	 * Returns the URL you can direct the user to for authorization
	 * @param OAuthToken $request_token
	 * @param string $callback_url
	 * @return string
	 */
	public function getAuthorizeUrl( OAuthToken $request_token ) {
		$url = $this->service_provider->authorization_uri() . '?oauth_token=' . $request_token->key;
		return $url;
	}
 
	/**
	 * Exchanges a RequestToken for a AccessToken
	 * @param OAuthToken $request_token
	 * @return OAuthToken
	 * @throws OAuthClientException
	 */
	public function getAccessToken( OAuthToken $request_token, $verifier ) {
		$req = OAuthRequest::from_consumer_and_token(
			$this->oauth_consumer,
			$request_token,
			'GET',
			$this->service_provider->access_token_uri()
		);
		$req->set_parameter('oauth_verifier', $verifier);
 
		$token_str = $this->_performRequest($req, $request_token);
		parse_str($token_str, $token_arr);
 
		if( isset($token_arr['oauth_token'], $token_arr['oauth_token_secret']) ) {
			return new OAuthToken($token_arr['oauth_token'], $token_arr['oauth_token_secret']);
		} else {
			return null;
		}
	}

	/**
	 * Call a URI at the SP signed..
	 * @param string $uri
	 * @param array $params
	 * @return string
	 * @throws OAuthClientException;
	 */
	public function call( $uri, $params ) {
		if( !$this->oauth_token ) return array();
 
		$req = OAuthRequest::from_consumer_and_token(
			$this->oauth_consumer,
			$this->oauth_token,
			'GET',
			$uri,
			$params
		);
 
		return $this->_performRequest($req);
	} 

	/**
	 * Performs a OAuthRequest, returning the response
	 * You can give a token to force signatures with this
	 * token. If none given, the token used when creating
	 * this instance of CampusNotesAPI is used
	 * @param OAuthRequest $req
	 * @param OAuthToken $token 
	 * @return string
	 * @throws CNApiException
	 */
	private function _performRequest( OAuthRequest $req, OAuthToken $token = null ) {
		$token = ($token) ? $token : $this->oauth_token;
		$req->sign_request($this->hmac_signature_method, $this->oauth_consumer, $token);

		$curl = curl_init();
 
		$params = $req->get_parameters();
 
		foreach( array_keys($params) AS $i )
			if( substr($i, 0, 6) == 'oauth_' ) 
				unset($params[$i]);
 
 
		$url = $req->get_normalized_http_url();
		if( $req->get_normalized_http_method() == 'POST' ) {
			curl_setopt($curl, CURLOPT_POST, true);
			curl_setopt($curl, CURLOPT_POSTFIELDS, http_build_query($params) );
		} else {
			if( count($params) )
				$url .= '?' . http_build_query($params);
		}
 
		curl_setopt($curl, CURLOPT_URL, $url);
		curl_setopt($curl, CURLOPT_RETURNTRANSFER, true);		
		curl_setopt($curl, CURLOPT_HTTPHEADER, array(
			$req->to_header()
		));
 
		$rtn = curl_exec($curl);
 
		if( !$rtn ) {
			throw new OAuthClientException( curl_error($curl) );
		} else if( curl_getinfo($curl, CURLINFO_HTTP_CODE) != 200 ) {
			throw new OAuthClientException( $rtn );
		} else {
			return $rtn;
		}
	}
}
 
?>