<?php
/**
 * 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/ 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         Alex Potsides, {@link http://www.achingbrain.net http://www.achingbrain.net}
 * @version        0.5
 * @copyright      Alex Potsides, {@link http://www.achingbrain.net http://www.achingbrain.net}
 * @license        http://www.opensource.org/licenses/bsd-license.php BSD License
 */

/**
 * The Akismet PHP5 Class
 *
 * This class takes the functionality from the Akismet NGCMS 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 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 $APIKey;
	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 $APIKey 		 API key.
	 */
	public function __construct($blogURL, $APIKey) {

		$this->blogURL = $blogURL;
		$this->APIKey = $APIKey;
		// 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->APIKey . '&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->APIKey . '.rest.akismet.com', '/' . $this->akismetVersion . '/comment-check');

		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->APIKey . '.' . $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->APIKey . '.' . $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 NGCMS 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, $this->errorString, 10);
		if ($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();
}

?>
