error.php

<?php

/* Eregansu: Fatal errors
 *
 * Copyright 2009-2011 Mo McRoberts.
 *
 *  Licensed under the Apache License, Version 2.0 (the "License");
 *  you may not use this file except in compliance with the License.
 *  You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 *  Unless required by applicable law or agreed to in writing, software
 *  distributed under the License is distributed on an "AS IS" BASIS,
 *  WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 *  See the License for the specific language governing permissions and
 *  limitations under the License.
 */

/**
 * @year 2009-2011
 * @include uses('error');
 * @since Available in Eregansu 1.0 and later. 
 */

if(!defined('TEMPLATES_PATH')) define('TEMPLATES_PATH', 'templates');

class TerminalErrorException extends Exception implements IRequestProcessor
{
	public $processed = false;

	public function process(Request $req)
	{
		if($this->processed)
		{
			return false;
		}
		$this->processed = true;
		return true;
	}
}

class Error extends TerminalErrorException
{
	const BAD_REQUEST = 400;
	const AUTHORIZATION_REQUIRED = 401;
	const PAYMENT_REQUIRED = 402;
	const FORBIDDEN = 403;
	const OBJECT_NOT_FOUND = 404;
	const ROUTE_NOT_MATCHED = '404.1';
	const NO_OBJECT = '404.2';
	const METHOD_NOT_ALLOWED = 405;
	const TYPE_NOT_SUPPORTED = 406;
	const PROXY_AUTHENTICATION_REQUIRED = 407;
	const REQUEST_TIMEOUT = 408;
	const CONFLICT = 409;
	const GONE = 410;
	const LENGTH_REQUIRED = 411;
	const PRECONDITION_FAILED = 412;
	const REQUEST_TOO_LARGE = 413;
	const URI_TOO_LONG = 414;
	const UNSUPPORTED_MEDIA_TYPE = 415;
	const RANGE_NOT_SATISFIABLE = 416;
	const EXPECTATION_FAILED = 417;
	
	const INTERNAL = 500;
	const NOT_IMPLEMENTED = 501;
	const METHOD_NOT_IMPLEMENTED = '501.1';
	const BAD_GATEWAY = 502;
	const SERVICE_UNAVAILABLE = 503;
	const ROUTE_NOT_PROCESSOR = '503.1';
	const GATEWAY_TIMEOUT = 504;
	const HTTP_VERSION_NOT_SUPPORTED = 505;
	const VARIANT_ALSO_NEGOTIATES = 506;
	const INSUFFICIENT_STORAGE = 507;
	const BANDWIDTH_LIMIT_EXCEEDED = 508;
	const NOT_EXTENDED = 509;
	
	public static $throw = false;

	protected $backtrace = null;
	
	protected static $titles = array(
		self::BAD_REQUEST => 'Bad request',
		self::AUTHORIZATION_REQUIRED => 'Authorization required',
		self::PAYMENT_REQUIRED => 'Payment required',
		self::FORBIDDEN => 'Forbidden',
		self::OBJECT_NOT_FOUND => 'Object not found',
		self::ROUTE_NOT_MATCHED => 'Route not matched',
		self::NO_OBJECT => 'No object specified',
		self::METHOD_NOT_ALLOWED => 'Method not allowed',
		self::TYPE_NOT_SUPPORTED => 'Type not supported',
		self::PROXY_AUTHENTICATION_REQUIRED => 'Proxy authentication required',
		self::REQUEST_TIMEOUT => 'Request timed out',
		self::CONFLICT => 'Conflict',
		self::GONE => 'Gone',
		self::LENGTH_REQUIRED => 'Length required',
		self::PRECONDITION_FAILED => 'Precondition failed',
		self::REQUEST_TOO_LARGE => 'Request too large',
		self::URI_TOO_LONG => 'URI too long',
		self::UNSUPPORTED_MEDIA_TYPE => 'Unsupported media type',
		self::RANGE_NOT_SATISFIABLE => 'Range not satisfiable',
		self::EXPECTATION_FAILED => 'Expectation failed',
		
		self::INTERNAL => 'Internal error',
		self::NOT_IMPLEMENTED => 'Not implemented',
		self::METHOD_NOT_IMPLEMENTED => 'Method not implemented',
		self::BAD_GATEWAY => 'Bad gateway',
		self::SERVICE_UNAVAILABLE => 'Service unavailable',
		self::GATEWAY_TIMEOUT => 'Gateway timed out',
		self::HTTP_VERSION_NOT_SUPPORTED => 'HTTP version not supported',
		self::VARIANT_ALSO_NEGOTIATES => 'Variant also negotiates',
		self::INSUFFICIENT_STORAGE => 'Insufficient storage',
		self::BANDWIDTH_LIMIT_EXCEEDED => 'Bandwidth limit exceeded',
		self::NOT_EXTENDED => 'Not extended',
	);
	
	/* %1$s is the requested object (with trailing space)
	 * %2$s is the request method
	 * %3$s is the request content type
	 */
	protected static $descriptions = array(
		self::BAD_REQUEST => 'Your request could not be processed because it was malformed.',
		self::AUTHORIZATION_REQUIRED => 'The requested object is not available without authentication.',
		self::PAYMENT_REQUIRED => 'Payment is required to access the requested object.',
		self::FORBIDDEN => 'Access to the object %1$swas denied.',
		self::OBJECT_NOT_FOUND => 'The requested object %1$scould not be found.',
		self::NO_OBJECT => 'Your request could not be processed because an object is required, but none was specified.',
		self::METHOD_NOT_ALLOWED => 'Your request could not be processed because the method %2$s is not supported by this object.',
		self::TYPE_NOT_SUPPORTED => 'Your request could not be processed because the requested type is not supported by the object %1$s',
		
		self::UNSUPPORTED_MEDIA_TYPE => 'Your request could not be processed because the submitted type %3$s is not supported by this object',
	);
	
	public $status = self::INTERNAL;
	public $detail = null;
	public $object = null;
	public $headers = array();

	public static function backtrace($skip = 1, $backtrace = null)
	{
		if($backtrace === null)
		{
			$backtrace = debug_backtrace();
		}
		$list = array();
		foreach($backtrace as $bt)
		{
			if(isset($bt['function']))
			{
				$func = $bt['function'];
				if(isset($bt['class']))
				{
					$func = $bt['class'] . $bt['type'] . $func . '()';
				}
			}
			else
			{
				$func = '(None)';
			}
			if(isset($bt['file']))
			{
				$location = $bt['file'] . ':' . $bt['line'];
			}
			if(isset($bt['object']))
			{
				$ctx = get_class($bt['object']);
			}
			else
			{
				$ctx = '';
			}
			$list[] = array($func, $ctx, $location);
		}
		if($skip)
		{
			return array_slice($list, $skip);
		}
		return $list;
	}

	public function __construct($aStatus = null, $object = null, $detail = null)
	{
		$this->backtrace = debug_backtrace();
		if($aStatus && !is_object($aStatus))
		{
			$this->status = $aStatus;
			$this->code = $this->status;
			$this->message = $this->statusTitle($this->status);
		}
		$this->object = $object;
		$this->detail = $detail;
	}
	
	public function process(Request $req)
	{	
		if(!parent::process($req))
		{
			return;
		}
		$title = $this->statusTitle($this->status);
		$desc = $this->statusDescription($this->status, $req);
		error_log($this->status . ' [' . $title . '] ' . $req->method . ' ' . $req->uri . ' ' . $this->detail);
		@header('HTTP/1.0 ' . floor($this->status) . ' ' . $title);
		foreach($this->headers as $name => $value)
		{
			if(is_numeric($name))
			{
				@header($value);
			}
			else
			{
				@header($name . ': ' . $value);
			}
		}
		$this->message = $title;
		$this->code = $this->status;
		if(!isset($req->types) || (!isset($req->types['text/html']) && !isset($req->types['*'])))
		{
			@header('Content-type: text/plain');			
			echo $title . " (" . $this->status . ")\n\n";
			/* On the command-line, we don't have to worry quite so much about who
			 * we the detailed information to.
			 */
			if($req instanceof CLIRequest)
			{
				if($this->detail)
				{
					echo $this->detail . "\n";
				}
				else
				{
					echo $desc . "\n";
				}
			}
			else
			{
				echo $desc . "\n\n";
				if(defined('EREGANSU_DEBUG') && EREGANSU_DEBUG)
				{
					echo $this->detail . "\n";
				}
			}
			if(self::$throw) throw $this;
			if($req) $req->abort();
			exit(1);
		}
		if(isset($req->data['errorSkin']) && isset($req->siteRoot) && file_exists($req->siteRoot . 'templates/' . $req->data['errorSkin'] . '/error.php'))
		{
			$this->errorTemplate($req, $req->data['errorSkin'], $title, $desc);
		}
		else if(defined('DEFAULT_ERROR_SKIN') && isset($req->siteRoot))
		{
			$path = $req->siteRoot . TEMPLATES_PATH . '/' . DEFAULT_ERROR_SKIN . '/error.php';
			if(file_exists($path))
			{
				$this->errorTemplate($req, DEFAULT_ERROR_SKIN, $title, $desc);
			}
		}
		if($req)
		{
			@$req->header('Content-type', 'text/html;charset=UTF-8');
		}
		echo '<!DOCTYPE html>' . "\n";
		echo '<html>' . "\n";
		echo "\t" . '<head>' . "\n";
		echo "\t\t" . '<meta charset="UTF-8">' . "\n";
		echo "\t\t" . '<title>' . _e($title) . '</title>' . "\n";
		echo "\t" . '</head>' . "\n";
		echo "\t" . '<body>' . "\n";
		echo "\t\t" . '<h1>' . _e($title) . '</h1>' . "\n";
		echo "\t\t" . '<p>' . _e($desc)  . '</p>' . "\n";
		echo $this->debugInfo();
		echo "\t" . '</body>' . "\n";
		echo '</html>' . "\n";
		if($req) $req->abort();		
		exit(1);
	}
	
	protected function errorTemplate(Request $request, $skin, $title, $desc)
	{
		error_reporting(0);
		$templates_iri = $request->root . 'templates/';
		$skin_iri = $template_root . $skin . '/';
		$templates_path = $request->siteRoot . TEMPLATES_PATH . '/';
		$skin_path = $templates_Path . $skin . '/';
		$detail = $this->detail;
		$debug = $this->debugInfo();
		require($request->siteRoot . TEMPLATES_PATH . '/' . $skin . '/error.php');
		$request->abort();
		exit(1);
	}
	
	protected function debugInfo()
	{
		ob_start();
		if(defined('EREGANSU_DEBUG') && EREGANSU_DEBUG)
		{
			if(strlen($this->detail))
			{
				echo '<pre>' . _e($this->detail) . '</pre>';
			}
			echo "\t\t" . '<hr />' . "\n";
			echo "\t\t" . '<h2>Backtrace:</h2>' . "\n";
			echo "\t\t" . '<table>' . "\n";
			echo "\t\t\t" . '<thead>' . "\n";
			echo "\t\t\t\t" . '<tr>' . "\n";
			echo "\t\t\t\t\t" . '<th scope="col">Function</th>' . "\n";
			echo "\t\t\t\t\t" . '<th scope="col">Context</th>' . "\n";
			echo "\t\t\t\t\t" . '<th scope="col">Called at</th>' . "\n";
			echo "\t\t\t\t" . '</tr>' . "\n";
			echo "\t\t\t" . '</thead>' . "\n";
			echo "\t\t\t" . '<tbody>' . "\n";
			foreach($this->backtrace as $bt)
			{
				if(isset($bt['function']))
				{
					$func = $bt['function'];
					if(isset($bt['class']))
					{
						$func = $bt['class'] . $bt['type'] . $func . '()';
					}
				}
				else
				{
					$func = '(None)';
				}
				if(isset($bt['file']))
				{
					$location = $bt['file'] . ':' . $bt['line'];
				}
				if(isset($bt['object']))
				{
					$ctx = get_class($bt['object']);
				}
				else
				{
					$ctx = '';
				}
				echo "\t\t\t\t<tr>\n";
				echo "\t\t\t\t\t<td>" . _e($func) . '</td>' . "\n";
				echo "\t\t\t\t\t<td>" . _e($ctx) . '</td>' . "\n";
				echo "\t\t\t\t\t<td>" . _e($location) . '</td>' . "\n";
				echo "\t\t\t\t</tr>\n";
			}
			echo "\t\t\t" . '</tbody>' . "\n";
			echo "\t\t" . '</table>' . "\n";
			echo "\t\t" . '<hr />' . "\n";
			echo "\t\t" . '<p>Error generated at ' . strftime('%Y-%m-%d %H:%M:%S') . ' UTC</p>';
		}
		return ob_get_clean();			
	}
	
	protected function statusTitle($code)
	{
		if(isset(self::$titles[$code])) return self::$titles[$code];
		$code = floor($code);
		if(isset(self::$titles[$code])) return self::$titles[$code];
		return 'Error';		
	}
	
	protected function statusDescription($code, Request $req)
	{
		$method = $req->method;
		if(isset($req->postData['__method'])) $method = $req->postData['__method'];
		if($this->object)
		{
			$object = $this->object;
		}
		else
		{
			$object = $req->uri;
		}
		if(strlen($object))
		{
			$object = $object . ' ';
		}
		if(isset(self::$descriptions[$code])) return sprintf(self::$descriptions[$code], $object, $method, $req->contentType);
		$code = floor($code);
		if(isset(self::$descriptions[$code])) return sprintf(self::$descriptions[$code], $object, $method, $req->contentType);
		if(strlen($object))
		{
			return 'An error occurred while attempting to process a ' . $method . ' request on ' . $object;
		}
		return 'An error occurred while attempting to process a ' . $method . ' request';
	}
}