<? php namespace Sayakb\Akismet;

/**
 * Akismet anti-comment spam service
 *
 * The class in this package allows use of the {@link http://akismet.com Akismet} anti-comment spam service in any PHP5 application. 
 *
 * This service performs a number of checks on submitted data and returns whether or not the data is likely to be spam. 
 *
 * Please note that in order to use this class, you must have a vaild {@link http://wordpress.com/api-keys/ WordPress API key}.   They are free for non/small-profit types and getting one will only take a couple of minutes. 
 *
 * For commercial use, please {@link http://akismet.com/commercial/ visit the Akismet commercial licensing page}. 
 *
 * Please be aware that this class is PHP5 only.   Attempts to run it under PHP4 will most likely fail. 
 *
 * See the Akismet class documentation page linked to below for usage information. 
 *
 * @package		akismet
 * @author		Ken Moini, {@link http://www.kenmoini.com http://www.kenmoini.com}
 * @author		Sayak Banerjee, {@link http://sayakbanerjee.com http://sayakbanerjee.com}
 * @version		0.5
 * @copyright	Ken Moini, {@link http://www.kenmoini.com http://www.kenmoini.com}
 * @copyright	Sayak Banerjee, {@link http://sayakbanerjee.com http://sayakbanerjee.com}
 * @license		http://www.opensource.org/licenses/bsd-license.php BSD License
 */

/**
 * The Akismet PHP5 Class
 *
 * This class takes the functionality from the Akismet WordPress plugin written by {@link http://photomatt.net/ Matt Mullenweg} and allows it to be integrated into any PHP5 application or website. 
 *
 * The original plugin is {@link http://akismet.com/download/ available on the Akismet website}. 
 *
 * <code>
 * $akismet = new Akismet('http://www.example.com/blog/', 'aoeu1aoue');
 * $akismet->setCommentAuthor($name);
 * $akismet->setCommentAuthorEmail($email);
 * $akismet->setCommentAuthorURL($url);
 * $akismet->setCommentContent($comment);
 * $akismet->setPermalink('http://www.example.com/blog/alex/someurl/');
 *
 * if($akismet->isCommentSpam())
 *   // store the comment but mark it as spam (in case of a mis-diagnosis)
 * else
 *   // store the comment normally
 * </code>
 *
 * Optionally you may wish to check if your WordPress API key is valid as in the example below. 
 *
 * <code>
 * $akismet = new Akismet('http://www.example.com/blog/', 'aoeu1aoue');
 *
 * if($akismet->isKeyValid()) {
 *   // api key is okay
 * } else {
 *   // api key is invalid
 * }
 * </code>
 *
 * @package	akismet
 * @name	Akismet
 * @version	0.5
 * @author	Alex Potsides
 * @link	http://www.achingbrain.net/
 */
class Akismet {
	private $version = '0.5';
	private $wordPressAPIKey;
	private $blogURL;
	private $comment;
	private $apiPort;
	private $akismetServer;
	private $akismetVersion;
	private $requestFactory;

	// This prevents some potentially sensitive information from being sent accross the wire. 
	private $ignore = array('HTTP_COOKIE',
							'HTTP_X_FORWARDED_FOR',
							'HTTP_X_FORWARDED_HOST',
							'HTTP_MAX_FORWARDS',
							'HTTP_X_FORWARDED_SERVER',
							'REDIRECT_STATUS',
							'SERVER_PORT',
							'PATH',
							'DOCUMENT_ROOT',
							'SERVER_ADMIN',
							'QUERY_STRING',
							'PHP_SELF' );

	/**
	 * @param	string	$blogURL			The URL of your blog. 
	 * @param	string	$wordPressAPIKey	WordPress API key. 
	 */
	public function __construct($blogURL, $wordPressAPIKey) {
		$this->blogURL = $blogURL;
		$this->wordPressAPIKey = $wordPressAPIKey;

		// Set some default values
		$this->apiPort = 80;
		$this->akismetServer = 'rest.akismet.com';
		$this->akismetVersion = '1.1';
		$this->requestFactory = new SocketWriteReadFactory();

		// Start to populate the comment data
		$this->comment['blog'] = $blogURL;

		if(isset($_SERVER['HTTP_USER_AGENT'])) {
			$this->comment['user_agent'] = $_SERVER['HTTP_USER_AGENT'];
		}

		if(isset($_SERVER['HTTP_REFERER'])) {
			$this->comment['referrer'] = $_SERVER['HTTP_REFERER'];
		}

		/*
		 * This is necessary if the server PHP5 is running on has been set up to run PHP4 and
		 * PHP5 concurently and is actually running through a separate proxy al a these instructions:
		 * http://www.schlitt.info/applications/blog/archives/83_How_to_run_PHP4_and_PHP_5_parallel.html
		 * and http://wiki.coggeshall.org/37.html
		 * Otherwise the user_ip appears as the IP address of the PHP4 server passing the requests to the
		 * PHP5 one...
		 */
		if(isset($_SERVER['REMOTE_ADDR']) && $_SERVER['REMOTE_ADDR'] ! = getenv('SERVER_ADDR')) {
			$this->comment['user_ip'] = $_SERVER['REMOTE_ADDR'];
		} else {
			$this->comment['user_ip'] = getenv('HTTP_X_FORWARDED_FOR');
		}
	}

	/**
	 * Makes a request to the Akismet service to see if the API key passed to the constructor is valid. 
	 *
	 * Use this method if you suspect your API key is invalid. 
	 *
	 * @return bool	True is if the key is valid, false if not. 
	 */
	public function isKeyValid() {
		// Check to see if the key is valid
		$response = $this->sendRequest('key=' .  $this->wordPressAPIKey . '& blog=' .  $this->blogURL, $this->akismetServer, '/' .  $this->akismetVersion . ' /verify-key');
		return $response[1] == 'valid';
	}

	// makes a request to the Akismet service
	private function sendRequest($request, $host, $path) {
		$http_request  = "POST " .  $path . "  HTTP/1.0\r\n";
		$http_request .= "Host: " .  $host . " \r\n";
		$http_request .= "Content-Type: application/x-www-form-urlencoded; charset=utf-8\r\n";
		$http_request .= "Content-Length: " .  strlen($request) . " \r\n";
		$http_request .= "User-Agent: Akismet PHP5 Class " .  $this->version . "  | Akismet/1.11\r\n";
		$http_request .= "\r\n";
		$http_request .= $request;

		$requestSender = $this->requestFactory->createRequestSender();
		$response = $requestSender->send($host, $this->apiPort, $http_request);

		return explode("\r\n\r\n", $response, 2);
	}

	// Formats the data for transmission
	private function getQueryString() {
		foreach($_SERVER as $key => $value) {
			if(!in_array($key, $this->ignore)) {
				if($key == 'REMOTE_ADDR') {
					$this->comment[$key] = $this->comment['user_ip'];
				} else {
					$this->comment[$key] = $value;
				}
			}
		}

		$query_string = '';

		foreach($this->comment as $key => $data) {
			if(!is_array($data)) {
				$query_string .= $key . ' =' .  urlencode(stripslashes($data)) . '&'; 
			}
		}

		return $query_string;
	}

	/**
	 * Tests for spam. 
	 *
	 * Uses the web service provided by {@link http://www.akismet.com Akismet} to see whether or not the submitted comment is spam.   Returns a boolean value. 
	 *
	 * @return	bool	True if the comment is spam, false if not
	 * @throws	Will throw an exception if the API key passed to the constructor is invalid. 
	 */
	public function isCommentSpam() {
		$response = $this->sendRequest($this->getQueryString(), $this->wordPressAPIKey . ' .rest.akismet.com', '/' .  $this->akismetVersion . ' /comment-check');

		if($response[1] == 'invalid' && ! $this->isKeyValid()) {
			throw new exception('The Wordpress API key passed to the Akismet constructor is invalid.   Please obtain a valid one from http://wordpress.com/api-keys/');
		}

		return ($response[1] == 'true');
	}

	/**
	 * Submit spam that is incorrectly tagged as ham. 
	 *
	 * Using this function will make you a good citizen as it helps Akismet to learn from its mistakes.   This will improve the service for everybody. 
	 */
	public function submitSpam() {
		$this->sendRequest($this->getQueryString(), $this->wordPressAPIKey . '.' .  $this->akismetServer, '/' .  $this->akismetVersion . ' /submit-spam');
	}

	/**
	 * Submit ham that is incorrectly tagged as spam. 
	 *
	 * Using this function will make you a good citizen as it helps Akismet to learn from its mistakes.   This will improve the service for everybody. 
	 */
	public function submitHam() {
		$this->sendRequest($this->getQueryString(), $this->wordPressAPIKey . '.' .  $this->akismetServer, '/' .  $this->akismetVersion . ' /submit-ham');
	}

	/**
	 * To override the user IP address when submitting spam/ham later on
	 *
	 * @param string $userip	An IP address.   Optional. 
	 */
	public function setUserIP($userip) {
		$this->comment['user_ip'] = $userip;
	}

	/**
	 * To override the referring page when submitting spam/ham later on
	 *
	 * @param string $referrer	The referring page.   Optional. 
	 */
	public function setReferrer($referrer) {
		$this->comment['referrer'] = $referrer;
	}

	/**
	 * A permanent URL referencing the blog post the comment was submitted to. 
	 *
	 * @param string $permalink	The URL.   Optional. 
	 */
	public function setPermalink($permalink) {
		$this->comment['permalink'] = $permalink;
	}

	/**
	 * The type of comment being submitted. 
	 *
	 * May be blank, comment, trackback, pingback, or a made up value like "registration" or "wiki". 
	 */
	public function setCommentType($commentType) {
		$this->comment['comment_type'] = $commentType;
	}

	/**
	 *	The name that the author submitted with the comment. 
	 */
	public function setCommentAuthor($commentAuthor) {
		$this->comment['comment_author'] = $commentAuthor;
	}

	/**
	 * The email address that the author submitted with the comment. 
	 *
	 * The address is assumed to be valid. 
	 */
	public function setCommentAuthorEmail($authorEmail) {
		$this->comment['comment_author_email'] = $authorEmail;
	}

	/**
	 * The URL that the author submitted with the comment. 
	 */
	public function setCommentAuthorURL($authorURL) {
		$this->comment['comment_author_url'] = $authorURL;
	}

	/**
	 * The comment's body text. 
	 */
	public function setCommentContent($commentBody) {
		$this->comment['comment_content'] = $commentBody;
	}

	/**
	 * Lets you override the user agent used to submit the comment. 
	 * you may wish to do this when submitting ham/spam. 
	 * Defaults to $_SERVER['HTTP_USER_AGENT']
	 */
	public function setCommentUserAgent($userAgent) {
		$this->comment['user_agent'] = $userAgent;
	}

	/**
	 * Defaults to 80
	 */
	public function setAPIPort($apiPort) {
		$this->apiPort = $apiPort;
	}

	/**
	 * Defaults to rest.akismet.com
	 */
	public function setAkismetServer($akismetServer) {
		$this->akismetServer = $akismetServer;
	}

	/**
	 * Defaults to '1.1'
	 *
	 * @param string $akismetVersion
	 */
	public function setAkismetVersion($akismetVersion) {
		$this->akismetVersion = $akismetVersion;
	}

	/**
	 * Used by unit tests to mock transport layer
	 *
	 * @param AkismetRequestFactory $requestFactory
	 */
	public function setRequestFactory($requestFactory) {
		$this->requestFactory = $requestFactory;
	}
}

/**
 * Used internally by Akismet
 *
 * This class is used by Akismet to do the actual sending and receiving of data.   It opens a connection to a remote host, sends some data and the reads the response and makes it available to the calling program. 
 *
 * The code that makes up this class originates in the Akismet WordPress plugin, which is {@link http://akismet.com/download/ available on the Akismet website}. 
 *
 * N.B. It is not necessary to call this class directly to use the Akismet class. 
 *
 * @package	akismet
 * @name	SocketWriteRead
 * @version	0.5
 * @author	Alex Potsides
 * @link	http://www.achingbrain.net/
 */
class SocketWriteRead implements AkismetRequestSender {
	private $response;
	private $errorNumber;
	private $errorString;

	public function __construct() {
		$this->errorNumber = 0;
		$this->errorString = '';
	}

	/**
	 *  Sends the data to the remote host. 
	 *
	 * @param	string	$host			The host to send/receive data. 
	 * @param	int		$port			The port on the remote host. 
	 * @param	string	$request		The data to send. 
	 * @param	int		$responseLength	The amount of data to read.   Defaults to 1160 bytes. 
	 * @throws	An exception is thrown if a connection cannot be made to the remote host. 
	 * @returns	The server response
	 */
	public function send($host, $port, $request, $responseLength = 1160) {
		$response = '';

		$fs = fsockopen($host, $port, $this->errorNumber, $this->errorString, 3);

		if($this->errorNumber ! = 0) {
			throw new Exception('Error connecting to host: ' .  $host . '  Error number: ' .  $this->errorNumber . '  Error message: ' .  $this->errorString);
		}

		if($fs ! == false) {
			@fwrite($fs, $request);

			while(!feof($fs)) {
				$response .= fgets($fs, $responseLength);
			}

			fclose($fs);
		}

		return $response;
	}

	/**
	 * Returns the server response text
	 *
	 * @return	string
	 */
	public function getResponse() {
		return $this->response;
	}

	/**
	 * Returns the error number
	 *
	 * If there was no error, 0 will be returned. 
	 *
	 * @return int
	 */
	public function getErrorNumner() {
		return $this->errorNumber;
	}

	/**
	 * Returns the error string
	 *
	 * If there was no error, an empty string will be returned. 
	 *
	 * @return string
	 */
	public function getErrorString() {
		return $this->errorString;
	}
}

/**
 * Used internally by the Akismet class and to mock the Akismet anti spam service in
 * the unit tests. 
 *
 * N.B. It is not necessary to call this class directly to use the Akismet class. 
 *
 * @package	akismet
 * @name	SocketWriteReadFactory
 * @version	0.5
 * @author	Alex Potsides
 * @link	http://www.achingbrain.net/
 */
class SocketWriteReadFactory implements AkismetRequestFactory {

	public function createRequestSender() {
		return new SocketWriteRead();
	}
}

/**
 * Used internally by the Akismet class and to mock the Akismet anti spam service in
 * the unit tests. 
 *
 * N.B. It is not necessary to implement this class to use the Akismet class. 
 *
 * @package	akismet
 * @name	AkismetRequestSender
 * @version	0.5
 * @author	Alex Potsides
 * @link	http://www.achingbrain.net/
 */
interface AkismetRequestSender {

	/**
	 *  Sends the data to the remote host. 
	 *
	 * @param	string	$host			The host to send/receive data. 
	 * @param	int		$port			The port on the remote host. 
	 * @param	string	$request		The data to send. 
	 * @param	int		$responseLength	The amount of data to read.   Defaults to 1160 bytes. 
	 * @throws	An exception is thrown if a connection cannot be made to the remote host. 
	 * @returns	The server response
	 */
	public function send($host, $port, $request, $responseLength = 1160);
}

/**
 * Used internally by the Akismet class and to mock the Akismet anti spam service in
 * the unit tests. 
 *
 * N.B. It is not necessary to implement this class to use the Akismet class. 
 *
 * @package	akismet
 * @name	AkismetRequestFactory
 * @version	0.5
 * @author	Alex Potsides
 * @link	http://www.achingbrain.net/
 */
interface AkismetRequestFactory {

	public function createRequestSender();
}
