Debugger.php

<?php
/**
 * Framework debugging and PHP error-handling class
 *
 * Provides enhanced logging, stack traces, and rendering debug views
 *
 * PHP 5
 *
 * CakePHP(tm) : Rapid Development Framework (http://cakephp.org)
 * Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
 *
 * Licensed under The MIT License
 * Redistributions of files must retain the above copyright notice.
 *
 * @copyright     Copyright 2005-2011, Cake Software Foundation, Inc. (http://cakefoundation.org)
 * @link          http://cakephp.org CakePHP(tm) Project
 * @package       Cake.Utility
 * @since         CakePHP(tm) v 1.2.4560
 * @license       MIT License (http://www.opensource.org/licenses/mit-license.php)
 */

/**
 * Included libraries.
 *
 */
App::uses('CakeLog', 'Log');
App::uses('String', 'Utility');

/**
 * Provide custom logging and error handling.
 *
 * Debugger overrides PHP's default error handling to provide stack traces and enhanced logging
 *
 * @package       Cake.Utility
 * @link          http://book.cakephp.org/2.0/en/development/debugging.html#debugger-class
 */
class Debugger {

/**
 * A list of errors generated by the application.
 *
 * @var array
 */
	public $errors = array();

/**
 * The current output format.
 *
 * @var string
 */
	protected $_outputFormat = 'js';

/**
 * Templates used when generating trace or error strings.  Can be global or indexed by the format
 * value used in $_outputFormat.
 *
 * @var string
 */
	protected $_templates = array(
		'log' => array(
			'trace' => '{:reference} - {:path}, line {:line}',
			'error' => "{:error} ({:code}): {:description} in [{:file}, line {:line}]"
		),
		'js' => array(
			'error' => '',
			'info' => '',
			'trace' => '<pre class="stack-trace">{:trace}</pre>',
			'code' => '',
			'context' => '',
			'links' => array()
		),
		'html' => array(
			'trace' => '<pre class="cake-error trace"><b>Trace</b> <p>{:trace}</p></pre>',
			'context' => '<pre class="cake-error context"><b>Context</b> <p>{:context}</p></pre>'
		),
		'txt' => array(
			'error' => "{:error}: {:code} :: {:description} on line {:line} of {:path}\n{:info}",
			'code' => '',
			'info' => ''
		),
		'base' => array(
			'traceLine' => '{:reference} - {:path}, line {:line}',
			'trace' => "Trace:\n{:trace}\n",
			'context' => "Context:\n{:context}\n",
		),
		'log' => array(),
	);

/**
 * Holds current output data when outputFormat is false.
 *
 * @var string
 */
	protected $_data = array();

/**
 * Constructor.
 *
 */
	public function __construct() {
		$docRef = ini_get('docref_root');

		if (empty($docRef) && function_exists('ini_set')) {
			ini_set('docref_root', 'http://php.net/');
		}
		if (!defined('E_RECOVERABLE_ERROR')) {
			define('E_RECOVERABLE_ERROR', 4096);
		}

		$e = '<pre class="cake-error">';
		$e .= '<a href="javascript:void(0);" onclick="document.getElementById(\'{:id}-trace\')';
		$e .= '.style.display = (document.getElementById(\'{:id}-trace\').style.display == ';
		$e .= '\'none\' ? \'\' : \'none\');"><b>{:error}</b> ({:code})</a>: {:description} ';
		$e .= '[<b>{:path}</b>, line <b>{:line}</b>]';

		$e .= '<div id="{:id}-trace" class="cake-stack-trace" style="display: none;">';
		$e .= '{:links}{:info}</div>';
		$e .= '</pre>';
		$this->_templates['js']['error'] = $e;

		$t = '<div id="{:id}-trace" class="cake-stack-trace" style="display: none;">';
		$t .= '{:context}{:code}{:trace}</div>';
		$this->_templates['js']['info'] = $t;

		$links = array();
		$link = '<a href="javascript:void(0);" onclick="document.getElementById(\'{:id}-code\')';
		$link .= '.style.display = (document.getElementById(\'{:id}-code\').style.display == ';
		$link .= '\'none\' ? \'\' : \'none\')">Code</a>';
		$links['code'] = $link;

		$link = '<a href="javascript:void(0);" onclick="document.getElementById(\'{:id}-context\')';
		$link .= '.style.display = (document.getElementById(\'{:id}-context\').style.display == ';
		$link .= '\'none\' ? \'\' : \'none\')">Context</a>';
		$links['context'] = $link;

		$this->_templates['js']['links'] = $links;

		$this->_templates['js']['context'] = '<pre id="{:id}-context" class="cake-context" ';
		$this->_templates['js']['context'] .= 'style="display: none;">{:context}</pre>';

		$this->_templates['js']['code'] = '<pre id="{:id}-code" class="cake-code-dump" ';
		$this->_templates['js']['code'] .= 'style="display: none;">{:code}</pre>';

		$e = '<pre class="cake-error"><b>{:error}</b> ({:code}) : {:description} ';
		$e .= '[<b>{:path}</b>, line <b>{:line}]</b></pre>';
		$this->_templates['html']['error'] = $e;

		$this->_templates['html']['context'] = '<pre class="cake-context"><b>Context</b> ';
		$this->_templates['html']['context'] .= '<p>{:context}</p></pre>';
	}

/**
 * Returns a reference to the Debugger singleton object instance.
 *
 * @param string $class
 * @return object
 */
	public static function &getInstance($class = null) {
		static $instance = array();
		if (!empty($class)) {
			if (!$instance || strtolower($class) != strtolower(get_class($instance[0]))) {
				$instance[0] = new $class();
			}
		}
		if (!$instance) {
			$instance[0] = new Debugger();
		}
		return $instance[0];
	}

/**
 * Recursively formats and outputs the contents of the supplied variable.
 *
 *
 * @param mixed $var the variable to dump
 * @return void
 * @see Debugger::exportVar()
 * @link http://book.cakephp.org/2.0/en/development/debugging.html#Debugger::dump
 */
	public static function dump($var) {
		pr(self::exportVar($var));
	}

/**
 * Creates an entry in the log file.  The log entry will contain a stack trace from where it was called.
 * as well as export the variable using exportVar. By default the log is written to the debug log.
 *
 * @param mixed $var Variable or content to log
 * @param integer $level type of log to use. Defaults to LOG_DEBUG
 * @return void
 * @link http://book.cakephp.org/2.0/en/development/debugging.html#Debugger::log
 */
	public static function log($var, $level = LOG_DEBUG) {
		$source = self::trace(array('start' => 1)) . "\n";
		CakeLog::write($level, "\n" . $source . self::exportVar($var));
	}

/**
 * Overrides PHP's default error handling.
 *
 * @param integer $code Code of error
 * @param string $description Error description
 * @param string $file File on which error occurred
 * @param integer $line Line that triggered the error
 * @param array $context Context
 * @return boolean true if error was handled
 * @deprecated This function is supersceeded by Debugger::outputError()
 */
	public static function showError($code, $description, $file = null, $line = null, $context = null) {
		$_this = Debugger::getInstance();

		if (empty($file)) {
			$file = '[internal]';
		}
		if (empty($line)) {
			$line = '??';
		}
		$path = self::trimPath($file);

		$info = compact('code', 'description', 'file', 'line');
		if (!in_array($info, $_this->errors)) {
			$_this->errors[] = $info;
		} else {
			return;
		}

		switch ($code) {
			case E_PARSE:
			case E_ERROR:
			case E_CORE_ERROR:
			case E_COMPILE_ERROR:
			case E_USER_ERROR:
				$error = 'Fatal Error';
				$level = LOG_ERROR;
			break;
			case E_WARNING:
			case E_USER_WARNING:
			case E_COMPILE_WARNING:
			case E_RECOVERABLE_ERROR:
				$error = 'Warning';
				$level = LOG_WARNING;
			break;
			case E_NOTICE:
			case E_USER_NOTICE:
				$error = 'Notice';
				$level = LOG_NOTICE;
			break;
			default:
				return;
			break;
		}

		$data = compact(
			'level', 'error', 'code', 'description', 'file', 'path', 'line', 'context'
		);
		echo $_this->outputError($data);

		if ($error == 'Fatal Error') {
			exit();
		}
		return true;
	}

/**
 * Outputs a stack trace based on the supplied options.
 *
 * ### Options
 *
 * - `depth` - The number of stack frames to return. Defaults to 999
 * - `format` - The format you want the return.  Defaults to the currently selected format.  If
 *    format is 'array' or 'points' the return will be an array.
 * - `args` - Should arguments for functions be shown?  If true, the arguments for each method call
 *   will be displayed.
 * - `start` - The stack frame to start generating a trace from.  Defaults to 0
 *
 * @param array $options Format for outputting stack trace
 * @return mixed Formatted stack trace
 * @link http://book.cakephp.org/2.0/en/development/debugging.html#Debugger::trace
 */
	public static function trace($options = array()) {
		$_this = Debugger::getInstance();
		$defaults = array(
			'depth'   => 999,
			'format'  => $_this->_outputFormat,
			'args'    => false,
			'start'   => 0,
			'scope'   => null,
			'exclude' => null
		);
		$options += $defaults;

		$backtrace = debug_backtrace();
		$count = count($backtrace);
		$back = array();

		$_trace = array(
			'line'     => '??',
			'file'     => '[internal]',
			'class'    => null,
			'function' => '[main]'
		);

		for ($i = $options['start']; $i < $count && $i < $options['depth']; $i++) {
			$trace = array_merge(array('file' => '[internal]', 'line' => '??'), $backtrace[$i]);

			if (isset($backtrace[$i + 1])) {
				$next = array_merge($_trace, $backtrace[$i + 1]);
				$reference = $next['function'];

				if (!empty($next['class'])) {
					$reference = $next['class'] . '::' . $reference . '(';
					if ($options['args'] && isset($next['args'])) {
						$args = array();
						foreach ($next['args'] as $arg) {
							$args[] = Debugger::exportVar($arg);
						}
						$reference .= join(', ', $args);
					}
					$reference .= ')';
				}
			} else {
				$reference = '[main]';
			}
			if (in_array($reference, array('call_user_func_array', 'trigger_error'))) {
				continue;
			}
			if ($options['format'] == 'points' && $trace['file'] != '[internal]') {
				$back[] = array('file' => $trace['file'], 'line' => $trace['line']);
			} elseif ($options['format'] == 'array') {
				$back[] = $trace;
			} else {
				if (isset($_this->_templates[$options['format']]['traceLine'])) {
					$tpl = $_this->_templates[$options['format']]['traceLine'];
				} else {
					$tpl = $_this->_templates['base']['traceLine'];
				}
				$trace['path'] = self::trimPath($trace['file']);
				$trace['reference'] = $reference;
				unset($trace['object'], $trace['args']);
				$back[] = String::insert($tpl, $trace, array('before' => '{:', 'after' => '}'));
			}
		}

		if ($options['format'] == 'array' || $options['format'] == 'points') {
			return $back;
		}
		return implode("\n", $back);
	}

/**
 * Shortens file paths by replacing the application base path with 'APP', and the CakePHP core
 * path with 'CORE'.
 *
 * @param string $path Path to shorten
 * @return string Normalized path
 */
	public static function trimPath($path) {
		if (!defined('CAKE_CORE_INCLUDE_PATH') || !defined('APP')) {
			return $path;
		}

		if (strpos($path, APP) === 0) {
			return str_replace(APP, 'APP' . DS, $path);
		} elseif (strpos($path, CAKE_CORE_INCLUDE_PATH) === 0) {
			return str_replace(CAKE_CORE_INCLUDE_PATH, 'CORE', $path);
		} elseif (strpos($path, ROOT) === 0) {
			return str_replace(ROOT, 'ROOT', $path);
		}

		if (strpos($path, CAKE) === 0) {
			return str_replace($corePath, 'CORE' . DS, $path);
		}
		return $path;
	}

/**
 * Grabs an excerpt from a file and highlights a given line of code.
 *
 * Usage:
 *
 * `Debugger::excerpt('/path/to/file', 100, 4);`
 *
 * The above would return an array of 8 items. The 4th item would be the provided line,
 * and would be wrapped in `<span class="code-highlight"></span>`.  All of the lines
 * are processed with highlight_string() as well, so they have basic PHP syntax highlighting
 * applied.
 *
 * @param string $file Absolute path to a PHP file
 * @param integer $line Line number to highlight
 * @param integer $context Number of lines of context to extract above and below $line
 * @return array Set of lines highlighted
 * @see http://php.net/highlight_string
 * @link http://book.cakephp.org/2.0/en/development/debugging.html#Debugger::excerpt
 */
	public static function excerpt($file, $line, $context = 2) {
		$lines = array();
		if (!file_exists($file)) {
			return array();
		}
		$data = @explode("\n", file_get_contents($file));

		if (empty($data) || !isset($data[$line])) {
			return;
		}
		for ($i = $line - ($context + 1); $i < $line + $context; $i++) {
			if (!isset($data[$i])) {
				continue;
			}
			$string = str_replace(array("\r\n", "\n"), "", highlight_string($data[$i], true));
			if ($i == $line) {
				$lines[] = '<span class="code-highlight">' . $string . '</span>';
			} else {
				$lines[] = $string;
			}
		}
		return $lines;
	}

/**
 * Converts a variable to a string for debug output.
 *
 * *Note:* The following keys will have their contents 
 * replaced with `*****`:
 *
 *  - password
 *  - login
 *  - host
 *  - database
 *  - port
 *  - prefix
 *  - schema
 *
 * This is done to protect database credentials, which could be accidentally
 * shown in an error message if CakePHP is deployed in development mode.
 *
 * @param string $var Variable to convert
 * @param integer $depth The depth to output to. Defaults to 3.
 * @return string Variable as a formatted string
 * @link http://book.cakephp.org/2.0/en/development/debugging.html#Debugger::exportVar
 */
	public static function exportVar($var, $depth = 3) {
		return self::_export($var, $depth, 0);
	}

/**
 * Protected export function used to keep track of indentation and recursion.
 *
 * @param mixed $var The variable to dump.
 * @param integer $depth The remaining depth.
 * @param integer $indent The current indentation level.
 * @return string The dumped variable.
 */
	protected static function _export($var, $depth, $indent) {
		switch (self::getType($var)) {
			case 'boolean':
				return ($var) ? 'true' : 'false';
			break;
			case 'integer':
				return '(int) ' . $var;
			case 'float':
				return '(float) ' . $var;
			break;
			case 'string':
				if (trim($var) == '') {
					return "''";
				}
				return "'" . h($var) . "'";
			break;
			case 'array':
				return self::_array($var, $depth - 1, $indent + 1);
			break;
			case 'resource':
				return strtolower(gettype($var));
			break;
			case 'null':
				return 'null';
			default:
				return self::_object($var, $depth - 1, $indent + 1);
			break;
		}
	}

/**
 * Export an array type object.  Filters out keys used in datasource configuration.
 *
 * @param array $var The array to export.
 * @param integer $depth The current depth, used for recursion tracking.
 * @param integer $indent The current indentation level.
 * @return string Exported array.
 */
	protected static function _array(array $var, $depth, $indent) {
		$var = array_merge($var,  array_intersect_key(array(
			'password' => '*****',
			'login'  => '*****',
			'host' => '*****',
			'database' => '*****',
			'port' => '*****',
			'prefix' => '*****',
			'schema' => '*****'
		), $var));

		$out = "array(";
		$n = $break = $end = null;
		if (!empty($var)) {
			$n = "\n";
			$break = "\n" . str_repeat("\t", $indent);
			$end = "\n" . str_repeat("\t", $indent - 1);
		}
		$vars = array();

		if ($depth >= 0) {
			foreach ($var as $key => $val) {
				$vars[] = $break . self::exportVar($key) .
					' => ' .
					self::_export($val, $depth - 1, $indent);
			}
		}
		return $out . implode(',', $vars) . $end . ')';
	}

/**
 * Handles object to string conversion.
 *
 * @param string $var Object to convert
 * @param integer $depth The current depth, used for tracking recursion.
 * @param integer $indent The current indentation level.
 * @return string
 * @see Debugger::exportVar()
 */
	protected static function _object($var, $depth, $indent) {
		$out = '';
		$props = array();

		$className = get_class($var);
		$out .= 'object(' . $className . ') {';

		if ($depth > 0) {
			$end = "\n" . str_repeat("\t", $indent - 1);
			$break = "\n" . str_repeat("\t", $indent);
			$objectVars = get_object_vars($var);
			foreach ($objectVars as $key => $value) {
				$value = self::_export($value, $depth - 1, $indent);
				$props[] = "$key => " . $value;
			}
			$out .= $break . implode($break, $props) . $end;
		}
		$out .= '}';
		return $out;
	}

/**
 * Get/Set the output format for Debugger error rendering.
 *
 * @param string $format The format you want errors to be output as.
 *   Leave null to get the current format.
 * @return mixed Returns null when setting.  Returns the current format when getting.
 * @throws CakeException when choosing a format that doesn't exist.
 */
	public static function outputAs($format = null) {
		$self = Debugger::getInstance();
		if ($format === null) {
			return $self->_outputFormat;
		}
		if ($format !== false && !isset($self->_templates[$format])) {
			throw new CakeException(__d('cake_dev', 'Invalid Debugger output format.'));
		}
		$self->_outputFormat = $format;
	}

/**
 * Add an output format or update a format in Debugger.
 *
 * `Debugger::addFormat('custom', $data);`
 *
 * Where $data is an array of strings that use String::insert() variable 
 * replacement.  The template vars should be in a `{:id}` style.  
 * An error formatter can have the following keys:
 *
 * - 'error' - Used for the container for the error message. Gets the following template
 *   variables: `id`, `error`, `code`, `description`, `path`, `line`, `links`, `info`
 * - 'info' - A combination of `code`, `context` and `trace`. Will be set with
 *   the contents of the other template keys.
 * - 'trace' - The container for a stack trace. Gets the following template
 *   variables: `trace`
 * - 'context' - The container element for the context variables. 
 *   Gets the following templates: `id`, `context`
 * - 'links' - An array of HTML links that are used for creating links to other resources.
 *   Typically this is used to create javascript links to open other sections.
 *   Link keys, are: `code`, `context`, `help`.  See the js output format for an 
 *   example.
 * - 'traceLine' - Used for creating lines in the stacktrace. Gets the following
 *   template variables: `reference`, `path`, `line`
 *
 * Alternatively if you want to use a custom callback to do all the formatting, you can use
 * the callback key, and provide a callable:
 *
 * `Debugger::addFormat('custom', array('callback' => array($foo, 'outputError'));`
 *
 * The callback can expect two parameters.  The first is an array of all
 * the error data. The second contains the formatted strings generated using
 * the other template strings.  Keys like `info`, `links`, `code`, `context` and `trace`
 * will be present depending on the other templates in the format type.
 *
 * @param string $format Format to use, including 'js' for JavaScript-enhanced HTML, 'html' for
 *    straight HTML output, or 'txt' for unformatted text.
 * @param array $strings Template strings, or a callback to be used for the output format.
 * @return The resulting format string set.
 */
	public static function addFormat($format, array $strings) {
		$self = Debugger::getInstance();
		if (isset($self->_templates[$format])) {
			if (isset($strings['links'])) {
				$self->_templates[$format]['links'] = array_merge(
					$self->_templates[$format]['links'],
					$strings['links']
				);
				unset($strings['links']);
			}
			$self->_templates[$format] = array_merge($self->_templates[$format], $strings);
		} else {
			$self->_templates[$format] = $strings;
		}
		return $self->_templates[$format];
	}

/**
 * Switches output format, updates format strings. 
 * Can be used to switch the active output format:
 *
 * @param string $format Format to use, including 'js' for JavaScript-enhanced HTML, 'html' for
 *    straight HTML output, or 'txt' for unformatted text.
 * @param array $strings Template strings to be used for the output format.
 * @return string
 * @deprecated Use Debugger::outputAs() and  Debugger::addFormat(). Will be removed 
 *   in 3.0
 */
	public function output($format = null, $strings = array()) {
		$_this = Debugger::getInstance();
		$data = null;

		if (is_null($format)) {
			return Debugger::outputAs();
		}

		if (!empty($strings)) {
			return Debugger::addFormat($format, $strings);
		}

		if ($format === true && !empty($_this->_data)) {
			$data = $_this->_data;
			$_this->_data = array();
			$format = false;
		}
		Debugger::outputAs($format);
		return $data;
	}

/**
 * Takes a processed array of data from an error and displays it in the chosen format.
 *
 * @param string $data
 * @return void
 */
	public function outputError($data) {
		$defaults = array(
			'level' => 0,
			'error' => 0,
			'code' => 0,
			'description' => '',
			'file' => '',
			'line' => 0,
			'context' => array(),
			'start' => 2,
		);
		$data += $defaults;

		$files = $this->trace(array('start' => $data['start'], 'format' => 'points'));
		$code = $this->excerpt($files[0]['file'], $files[0]['line'] - 1, 1);
		$trace = $this->trace(array('start' => $data['start'], 'depth' => '20'));
		$insertOpts = array('before' => '{:', 'after' => '}');
		$context = array();
		$links = array();
		$info = '';

		foreach ((array)$data['context'] as $var => $value) {
			$context[] = "\${$var}\t=\t" . $this->exportVar($value, 1);
		}

		switch ($this->_outputFormat) {
			case false:
				$this->_data[] = compact('context', 'trace') + $data;
				return;
			case 'log':
				$this->log(compact('context', 'trace') + $data);
				return;
		}

		$data['trace'] = $trace;
		$data['id'] = 'cakeErr' . uniqid();
		$tpl = array_merge($this->_templates['base'], $this->_templates[$this->_outputFormat]);
		$insert = array('context' => join("\n", $context)) + $data;

		$detect = array('context');

		if (isset($tpl['links'])) {
			foreach ($tpl['links'] as $key => $val) {
				if (in_array($key, $detect) && empty($insert[$key])) {
					continue;
				}
				$links[$key] = String::insert($val, $insert, $insertOpts);
			}
		}

		foreach (array('code', 'context', 'trace') as $key) {
			if (empty($$key) || !isset($tpl[$key])) {
				continue;
			}
			if (is_array($$key)) {
				$$key = join("\n", $$key);
			}
			$info .= String::insert($tpl[$key], compact($key) + $insert, $insertOpts);
		}
		$links = join(' ', $links);
		unset($data['context']);
		if (isset($tpl['callback']) && is_callable($tpl['callback'])) {
			return call_user_func($tpl['callback'], $data, compact('links', 'info'));
		}
		echo String::insert($tpl['error'], compact('links', 'info') + $data, $insertOpts);
	}

/**
 * Get the type of the given variable. Will return the classname
 * for objects.
 *
 * @param mixed $var The variable to get the type of
 * @return string The type of variable.
 */
	public static function getType($var) {
		if (is_object($var)) {
			return get_class($var); 
		}
		if (is_null($var)) {
			return 'null';
		}
		if (is_string($var)) {
			return 'string';
		}
		if (is_array($var)) {
			return 'array';
		}
		if (is_int($var)) {
			return 'integer';
		}
		if (is_bool($var)) {
			return 'boolean';
		}
		if (is_float($var)) {
			return 'float';
		}
		if (is_resource($var)) {
			return 'resource';
		}
		return 'unknown';
	}

/**
 * Verifies that the application's salt and cipher seed value has been changed from the default value.
 *
 * @return void
 */
	public static function checkSecurityKeys() {
		if (Configure::read('Security.salt') == 'DYhG93b0qyJfIxfs2guVoUubWwvniR2G0FgaC9mi') {
			trigger_error(__d('cake_dev', 'Please change the value of \'Security.salt\' in app/Config/core.php to a salt value specific to your application'), E_USER_NOTICE);
		}

		if (Configure::read('Security.cipherSeed') === '76859309657453542496749683645') {
			trigger_error(__d('cake_dev', 'Please change the value of \'Security.cipherSeed\' in app/Config/core.php to a numeric (digits only) seed value specific to your application'), E_USER_NOTICE);
		}
	}

}