site = $site;
}
public function listen()
{
$runner = new RequestHandlerRunner(
$this->safelyBootAndGetHandler(),
new SapiEmitter,
[ServerRequestFactory::class, 'fromGlobals'],
function (Throwable $e) {
$generator = new ErrorResponseGenerator;
return $generator($e, new ServerRequest, new Response);
}
);
$runner->run();
}
/**
* Try to boot Flarum, and retrieve the app's HTTP request handler.
*
* We catch all exceptions happening during this process and format them to
* prevent exposure of sensitive information.
*
* @return \Psr\Http\Server\RequestHandlerInterface
*/
private function safelyBootAndGetHandler()
{
try {
return $this->site->bootApp()->getRequestHandler();
} catch (Throwable $e) {
// Apply response code first so whatever happens, it's set before anything is printed
http_response_code(500);
try {
$this->cleanBootExceptionLog($e);
} catch (Throwable $e) {
// Ignore errors in logger. The important goal is to log the original error
}
$this->fallbackBootExceptionLog($e);
}
}
/**
* Attempt to log the boot exception in a clean way and stop the script execution.
* This means looking for debug mode and/or our normal error logger.
* There is always a risk for this to fail,
* for example if the container bindings aren't present
* or if there is a filesystem error.
* @param Throwable $error
*/
private function cleanBootExceptionLog(Throwable $error)
{
if (app()->has('flarum.config') && app('flarum.config')->inDebugMode()) {
// If the application booted far enough for the config to be available, we will check for debug mode
// Since the config is loaded very early, it is very likely to be available from the container
$message = $error->getMessage();
$file = $error->getFile();
$line = $error->getLine();
$type = get_class($error);
echo <<
$message
thrown in $file on line $line
$error
ERROR;
exit(1);
} elseif (app()->has(LoggerInterface::class)) {
// If the application booted far enough for the logger to be available, we will log the error there
// Considering most boot errors are related to database or extensions, the logger should already be loaded
// We check for LoggerInterface binding because it's a constructor dependency of LogReporter,
// then instantiate LogReporter through the container for automatic dependency injection
app(LogReporter::class)->report($error);
echo 'Flarum encountered a boot error. Details have been logged to the Flarum log file.';
exit(1);
}
}
/**
* If the clean logging doesn't work, then we have a last opportunity.
* Here we need to be extra careful not to include anything that might be sensitive on the page.
* @param Throwable $error
* @throws Throwable
*/
private function fallbackBootExceptionLog(Throwable $error)
{
echo 'Flarum encountered a boot error. Details have been logged to the system PHP log file.
';
// Throwing the exception ensures it will be visible with PHP display_errors=On
// but invisible if that feature is turned off
// PHP will also automatically choose a valid place to log it based on the system settings
throw $error;
}
}