<?php
class ErrorHandler
{
/**
* Displays an error message and stops script execution.
* If CONFIG_DEBUG is true, it will also dump a stack trace
* and all globally defined variables.
* (As this might reveal sensitive data you should never enable it in production)
*/
public static function traceError($message)
{
if ((defined('API') && API) || (defined('AJAX') && AJAX) || php_sapi_name() === 'cli') {
error_log('API ERROR: ' . $message);
error_log(self::formatBacktracePlain(debug_backtrace()));
}
if (php_sapi_name() === 'cli') {
// Don't spam HTML when invoked via cli, above error_log should have gone to stdout/stderr
exit(1);
}
Header('HTTP/1.1 500 Internal Server Error');
if (isset($_SERVER['HTTP_ACCEPT']) && strpos($_SERVER['HTTP_ACCEPT'], 'html') === false) {
Header('Content-Type: text/plain; charset=utf-8');
echo 'API ERROR: ', $message, "\n", self::formatBacktracePlain(debug_backtrace());
exit(0);
}
Header('Content-Type: text/html; charset=utf-8');
echo '<!DOCTYPE html><html lang="en"><head><meta charset="utf-8"><style>', "\n",
".arg { color: red; background: white; }\n",
"h1 a { color: inherit; text-decoration: inherit; font-weight: inherit; }\n",
'</style><title>Fatal Error</title></head><body>';
echo '<h1>Flagrant <a href="https://www.youtube.com/watch?v=7rrZ-sA4FQc&t=2m2s" target="_blank">S</a>ystem error</h1>';
echo "<h2>Message</h2><pre>$message</pre>";
if (strpos($message, 'Database') !== false) {
echo '<div><a href="install.php">Try running database setup</a></div>';
}
echo "<br><br>";
if (defined('CONFIG_DEBUG') && CONFIG_DEBUG) {
global $SLX_ERRORS;
if (!empty($SLX_ERRORS)) {
echo '<h2>PHP Errors</h2><pre>';
foreach ($SLX_ERRORS as $error) {
echo htmlspecialchars("{$error['errstr']} ({$error['errfile']}:{$error['errline']}\n");
}
echo '</pre>';
}
echo "<h2>Stack Trace</h2>";
echo '<pre>', self::formatBacktraceHtml(debug_backtrace()), '</pre>';
echo "<h2>Globals</h2><pre>";
echo htmlspecialchars(print_r($GLOBALS, true));
echo '</pre>';
} else {
echo <<<SADFACE
<pre>
________________________¶¶¶¶¶¶¶¶¶¶¶¶¶¶¶¶¶¶¶________
____________________¶¶¶___________________¶¶¶¶_____
________________¶¶¶_________________________¶¶¶¶___
______________¶¶______________________________¶¶¶__
___________¶¶¶_________________________________¶¶¶_
_________¶¶_____________________________________¶¶¶
________¶¶_________¶¶¶¶¶___________¶¶¶¶¶_________¶¶
______¶¶__________¶¶¶¶¶¶__________¶¶¶¶¶¶_________¶¶
_____¶¶___________¶¶¶¶____________¶¶¶¶___________¶¶
____¶¶___________________________________________¶¶
___¶¶___________________________________________¶¶_
__¶¶____________________¶¶¶¶____________________¶¶_
_¶¶_______________¶¶¶¶¶¶¶¶¶¶¶¶¶¶¶______________¶¶__
_¶¶____________¶¶¶¶___________¶¶¶¶¶___________¶¶___
¶¶¶_________¶¶¶__________________¶¶__________¶¶____
¶¶_________¶______________________¶¶________¶¶_____
¶¶¶______¶________________________¶¶_______¶¶______
¶¶¶_____¶_________________________¶¶_____¶¶________
_¶¶¶___________________________________¶¶__________
__¶¶¶________________________________¶¶____________
___¶¶¶____________________________¶¶_______________
____¶¶¶¶______________________¶¶¶__________________
_______¶¶¶¶¶_____________¶¶¶¶¶_____________________
</pre>
SADFACE;
}
echo '</body></html>';
exit(0);
}
public static function formatBacktraceHtml($trace): string
{
$output = '';
foreach ($trace as $idx => $line) {
$args = array();
foreach ($line['args'] as $arg) {
$arg = self::formatArgument($arg);
$args[] = '<span class="arg">' . htmlspecialchars($arg) . '</span>';
}
$frame = str_pad('#' . $idx, 3, ' ', STR_PAD_LEFT);
$function = htmlspecialchars($line['function']);
$args = implode(', ', $args);
$file = preg_replace('~(/[^/]+)$~', '<b>$1</b>', htmlspecialchars($line['file']));
// Add line
$output .= $frame . ' ' . $function . '<b>(</b>'
. $args . '<b>)</b>' . ' @ <i>' . $file . '</i>:' . $line['line'] . "\n";
}
return $output;
}
public static function formatBacktracePlain($trace): string
{
$output = '';
foreach ($trace as $idx => $line) {
$args = array();
foreach ($line['args'] as $arg) {
$args[] = self::formatArgument($arg);
}
$frame = str_pad('#' . $idx, 3, ' ', STR_PAD_LEFT);
$args = implode(', ', $args);
// Add line
$output .= "\n" . $frame . ' ' . $line['function'] . '('
. $args . ')' . ' @ ' . $line['file'] . ':' . $line['line'];
}
return $output;
}
private static function formatArgument($arg, $expandArray = true)
{
if (is_string($arg)) {
$arg = "'$arg'";
} elseif (is_object($arg)) {
$arg = 'instanceof ' . get_class($arg);
} elseif (is_array($arg)) {
if ($expandArray && count($arg) < 20) {
$expanded = '';
foreach ($arg as $key => $value) {
if (!empty($expanded)) {
$expanded .= ', ';
}
$expanded .= $key . ': ' . self::formatArgument($value, false);
if (strlen($expanded) > 200)
break;
}
if (strlen($expanded) <= 200)
return '[' . $expanded . ']';
}
$arg = 'Array(' . count($arg) . ')';
}
return $arg;
}
}
