gistfile1.php

<?php

/**
 * A Client for Campus Notes' (http://getcampusnotes.com) API
 *
 * @requires OAuth-php (http://oauth.googlecode.com/svn/code/php/) *
 * @copyright Campus Notes (C) 2009
 */

/**
 * The exception thrown when something bad happens in CampusNotesAPI
 */
class CNApiException extends Exception {}

/**
 * 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 CampusNotesAPI {
	private $oauth_consumer;
	private $oauth_token;
	private $hmac_signature_method;
	
	const REQUEST_URL = 'http://127.0.0.1/~fangel/campusnotes/api/request_token';
	const AUTH_URL = 'http://127.0.0.1/~fangel/campusnotes/api/authorize';
	const ACCESS_URL = 'http://127.0.0.1/~fangel/campusnotes/api/access_token';
	const API_URL = 'http://127.0.0.1/~fangel/campusnotes/api/json';
	
	/**
	 * Create a new CampusNotesAPI instance
	 * @param OAuthConsumer $c Your consumer info
	 * @param OAuthToken $t Your AccessToken (null if none)
	 */
	public function __construct( OAuthConsumer $c, OAuthToken $t = null ) {
		$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 CNApiException
	 * @return OAuthToken
	 */
	public function getRequestToken( $callback = 'oob' ) {
		$req = OAuthRequest::from_consumer_and_token(
			$this->oauth_consumer,
			null,
			'GET',
			self::REQUEST_URL
		);
		$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 = self::AUTH_URL . '?oauth_token=' . $request_token->key;
		return $url;
	}
	
	/**
	 * Exchanges a RequestToken for a AccessToken
	 * @param OAuthToken $request_token
	 * @return OAuthToken
	 * @throws CNApiException
	 */
	public function getAccessToken( OAuthToken $request_token, $verifier ) {
		$req = OAuthRequest::from_consumer_and_token(
			$this->oauth_consumer,
			$request_token,
			'GET',
			self::ACCESS_URL
		);
		$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 method at CampusNotes
	 * @param string $method
	 * @param array $params
	 * @return array
	 * @throws CNApiException;
	 */
	public function call( $method, $params ) {
		if( !$this->oauth_token ) return array();
		$params['method'] = $method;
		
		$req = OAuthRequest::from_consumer_and_token(
			$this->oauth_consumer,
			$this->oauth_token,
			'GET',
			self::API_URL,
			$params
		);
		
		$json_str = $this->_performRequest($req);
		$json = json_decode($json_str);
		
		if( isset($json->error) ) {
			throw new CNApiException( $json->msg );
		} else {
			return $json;
		}
	}
	
	/**
	 * 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( !$rtn ) {
			throw new CNApiException( curl_error($curl) );
		} else if( curl_getinfo($curl, CURLINFO_HTTP_CODE) != 200 ) {
			throw new CNApiException( $rtn );
		} else {
			return $rtn;
		}
	}
}

?>