Refactor exception handling into dedicated class

Signed-off-by: Florian Pritz <bluewind@xinu.at>

1 files changed, 154 insertions, 0 deletions

diff --git a/application/libraries/ExceptionHandler.php b/application/libraries/ExceptionHandler.php
new file mode 100644
index 000000000..7dc954f2b
--- /dev/null
+++ b/application/libraries/ExceptionHandler.php
@@ -0,0 +1,154 @@
+<?php
+/*
+ * Copyright 2015 Florian "Bluewind" Pritz <bluewind@server-speed.net>
+ *
+ * Licensed under AGPLv3
+ * (see COPYING for full license text)
+ *
+ */
+
+namespace libraries;
+
+class ExceptionHandler {
+	static function setup()
+	{
+		set_error_handler(array("\libraries\ExceptionHandler", "error_handler"));
+		set_exception_handler(array("\libraries\ExceptionHandler", 'exception_handler'));
+		register_shutdown_function(array("\libraries\ExceptionHandler", "check_for_fatal"));
+		assert_options(ASSERT_ACTIVE, true);
+		assert_options(ASSERT_CALLBACK, array("\libraries\ExceptionHandler", '_assert_failure'));
+	}
+
+	static function error_handler($errno, $errstr, $errfile, $errline)
+	{
+		if (!(error_reporting() & $errno)) {
+			// This error code is not included in error_reporting
+			return;
+		}
+		throw new \ErrorException($errstr, 0, $errno, $errfile, $errline);
+	}
+
+	// Source: https://gist.github.com/abtris/1437966
+	static private function getExceptionTraceAsString($exception) {
+		$rtn = "";
+		$count = 0;
+		foreach ($exception->getTrace() as $frame) {
+			$args = "";
+			if (isset($frame['args'])) {
+				$args = array();
+				foreach ($frame['args'] as $arg) {
+					if (is_string($arg)) {
+						$args[] = "'" . $arg . "'";
+					} elseif (is_array($arg)) {
+						$args[] = "Array";
+					} elseif (is_null($arg)) {
+						$args[] = 'NULL';
+					} elseif (is_bool($arg)) {
+						$args[] = ($arg) ? "true" : "false";
+					} elseif (is_object($arg)) {
+						$args[] = get_class($arg);
+					} elseif (is_resource($arg)) {
+						$args[] = get_resource_type($arg);
+					} else {
+						$args[] = $arg;
+					}
+				}
+				$args = join(", ", $args);
+			}
+			$rtn .= sprintf( "#%s %s(%s): %s(%s)\n",
+				$count,
+				isset($frame['file']) ? $frame['file'] : 'unknown file',
+				isset($frame['line']) ? $frame['line'] : 'unknown line',
+				(isset($frame['class']))  ? $frame['class'].$frame['type'].$frame['function'] : $frame['function'],
+				$args );
+			$count++;
+		}
+		return $rtn;
+	}
+
+	static public function log_exception($ex)
+	{
+		$exceptions = array($ex);
+		while ($ex->getPrevious() !== null) {
+			$ex = $ex->getPrevious();
+			$exceptions[] = $ex;
+		}
+
+		foreach ($exceptions as $key => $e) {
+			$message = sprintf("Exception %d/%d '%s' with message '%s' in %s:%d\n", $key+1, count($exceptions), get_class($e), $e->getMessage(), $e->getFile(), $e->getLine());
+			if (method_exists($e, "get_error_id")) {
+				$message .= 'Error ID: '.$e->get_error_id()."\n";
+			}
+			if (method_exists($e, "get_data") && $e->get_data() !== NULL) {
+				$message .= 'Data: '.var_export($e->get_data(), true)."\n";
+			}
+			$message .= "Backtrace:\n".self::getExceptionTraceAsString($e)."\n";
+			error_log($message);
+		}
+	}
+
+	// The actual exception handler
+	static public function exception_handler($ex)
+	{
+		self::log_exception($ex);
+
+		$display_errors = in_array(strtolower(ini_get('display_errors')), array('1', 'on', 'true', 'stdout'));
+		if (php_sapi_name() === 'cli' OR defined('STDIN')) {
+			$display_errors = true;
+		}
+
+		$GLOBALS["is_error_page"] = true;
+		$heading = "Internal Server Error";
+		$message = "<p>An unhandled error occured.</p>\n";
+
+		if ($display_errors) {
+			$exceptions = array($ex);
+			while ($ex->getPrevious() !== null) {
+				$ex = $ex->getPrevious();
+				$exceptions[] = $ex;
+			}
+
+			foreach ($exceptions as $key => $e) {
+				$backtrace = self::getExceptionTraceAsString($e);
+				$message .= '<div>';
+				$message .= '<b>Exception '.($key+1).' of '.count($exceptions).'</b><br>';
+				$message .= '<b>Fatal error</b>:  Uncaught exception '.htmlspecialchars(get_class($e)).'<br>';
+				$message .= '<b>Message</b>: '.htmlspecialchars($e->getMessage()).'<br>';
+				if (method_exists($e, "get_error_id")) {
+					$message .= '<b>Error ID</b>: '.htmlspecialchars($e->get_error_id()).'<br>';
+				}
+				if (method_exists($e, "get_data") && $e->get_data() !== NULL) {
+					$message .= '<b>Data</b>: <pre>'.htmlspecialchars(var_export($e->get_data(), true)).'</pre><br>';
+				}
+				$message .= '<b>Backtrace:</b><br>';
+				$message .= '<pre>'.htmlspecialchars(str_replace(FCPATH, "./", $backtrace)).'</pre>';
+				$message .= 'thrown in <b>'.htmlspecialchars($e->getFile()).'</b> on line <b>'.htmlspecialchars($e->getLine()).'</b><br>';
+				$message .= '</div>';
+			}
+		} else {
+			$message .="<p>More information can be found in the php error log or by enabling display_errors.</p>";
+		}
+
+		$message = "$message";
+		include FCPATH.APPPATH."/errors/error_general.php";
+	}
+
+	/**
+	 * Checks for a fatal error, work around for set_error_handler not working on fatal errors.
+	 */
+	static public function check_for_fatal()
+	{
+		$error = error_get_last();
+		if ($error["type"] == E_ERROR) {
+			self::exception_handler(new \ErrorException(
+				$error["message"], 0, $error["type"], $error["file"], $error["line"]));
+		}
+	}
+
+	static public function assert_failure($file, $line, $expr, $message = "")
+	{
+		self::exception_handler(new Exception("assert($expr): Assertion failed in $file at line $line".($message != "" ? " with message: '$message'" : "")));
+		exit(1);
+	}
+
+}