silverstripe-framework/Logging/DetailedErrorFormatter.php

<?php

namespace SilverStripe\Logging;

use SilverStripe\Dev\Debug;
use Monolog\Formatter\FormatterInterface;
use Exception;

/**
 * Monolog-compatible error handler that will output a detailed error message to the screen.
 */
class DetailedErrorFormatter implements FormatterInterface
{
	public function format(array $record)
	{
		if(isset($record['context']['exception'])) {
			/** @var Exception $exception */
			$exception = $record['context']['exception'];
			$context = array(
				'code' => $exception->getCode(),
				'message' => 'Uncaught ' . get_class($exception) . ': ' . $exception->getMessage(),
				'file' => $exception->getFile(),
				'line' => $exception->getLine(),
				'trace' => $exception->getTrace(),
			);
		} else {
			$context = $record['context'];
			foreach(array('code','message','file','line') as $key) {
				if(!isset($context[$key])) {
					$context[$key] = isset($record[$key]) ? $record[$key] : null;
				}
			}

			$trace = debug_backtrace();

			// Filter out monolog plumbing from the trace
			// If the context file & line isn't found in the trace, then the trace is most likely
			// call to the fatal error handler and is not useful, so exclude it entirely
			$i = $this->findInTrace($trace, $context['file'], $context['line']);
			if($i !== null) {
				$context['trace'] = array_slice($trace, $i);
			} else {
				$context['trace'] = null;
			}
		}

		return $this->output(
			$context['code'],
			$context['message'],
			$context['file'],
			$context['line'],
			$context['trace']
		);
	}

	public function formatBatch(array $records) {
		return implode("\n", array_map(array($this, 'format'), $records));
	}

	/**
	 * Find a call on the given file & line in the trace
	 * @param array $trace The result of debug_backtrace()
	 * @param string $file The filename to look for
	 * @param string $line The line number to look for
	 * @return int|null The matching row number, if found, or null if not found
	 */
	protected function findInTrace(array $trace, $file, $line) {
		foreach($trace as $i => $call) {
			if(isset($call['file']) && isset($call['line']) && $call['file'] == $file && $call['line'] == $line) {
				return $i;
			}
		}
		return null;
	}

	/**
	 * Render a developer facing error page, showing the stack trace and details
	 * of the code where the error occured.
	 *
	 * @param int $errno
	 * @param string $errstr
	 * @param string $errfile
	 * @param int $errline
	 * @param array $errcontext
	 * @return string
	 */
	protected function output($errno, $errstr, $errfile, $errline, $errcontext) {
		$reporter = Debug::create_debug_view();

		// Coupling alert: This relies on knowledge of how the director gets its URL, it could be improved.
		$httpRequest = null;
		if(isset($_SERVER['REQUEST_URI'])) {
			$httpRequest = $_SERVER['REQUEST_URI'];
		} elseif(isset($_REQUEST['url'])) {
			$httpRequest = $_REQUEST['url'];
		}
		if(isset($_SERVER['REQUEST_METHOD'])) {
			$httpRequest = $_SERVER['REQUEST_METHOD'] . ' ' . $httpRequest;
		}

		$output = $reporter->renderHeader();
		$output .= $reporter->renderError($httpRequest, $errno, $errstr, $errfile, $errline);

		if(file_exists($errfile)) {
			$lines = file($errfile);

			// Make the array 1-based
			array_unshift($lines, "");
			unset($lines[0]);

			$offset = $errline-10;
			$lines = array_slice($lines, $offset, 16, true);
			$output .= $reporter->renderSourceFragment($lines, $errline);
		}
		$output .= $reporter->renderTrace($errcontext);
		$output .= $reporter->renderFooter();

		return $output;
	}
}