[debugging] How to display errors on laravel 4?

I'm trying to create an app on Laravel 4 beta but I can't debug it because it doesn't show any error, display_errors is on, error_reporting is E_ALL and debug => true (config/app.php). When I try to do an error on public/index.php it shows a parse error, but when I do it on the router it just shows a blank page (White screen of death). How can I fix this?

Thank you

Inside config folder open app.php

Change

'debug' => false,

to

'debug' => true, 

I had a problem with the white screen after installing a new laravel instance. I couldn't find anything in the logs because (eventually I found out) that the reason for the white screen was that app/storage wasn't writable.

In order to get an error message on the screen I added the following to the public/index.php

try {
    $app->run();
} catch(\Exception $e) {
    echo "<pre>";
    echo $e;
    echo "</pre>";
}

After that it was easy to solve the problem.

Following the good advice by @The Shift Exchange I looked at the error_log and indeed managed to solve to problem. it was simply a permissions issue:

Tue Feb 26 11:22:20 2013] [error] [client 127.0.0.1] PHP Fatal error:  Uncaught exception 'UnexpectedValueException' with message 'The stream or file "/Users/matanya/Sites/indgo/app/start/../storage/logs/log-apache2handler-2013-02-26.txt" could not be opened: failed to open stream: Permission denied' in /Users/matanya/Sites/indgo/vendor/monolog/monolog/src/Monolog/Handler/StreamHandler.php:71\nStack trace:\n#0 /Users/matanya/Sites/indgo/vendor/monolog/monolog/src/Monolog/Handler/RotatingFileHandler.php(77): Monolog\\Handler\\StreamHandler->write(Array)\n#1 /Users/matanya/Sites/indgo/vendor/monolog/monolog/src/Monolog/Handler/AbstractProcessingHandler.php(37): Monolog\\Handler\\RotatingFileHandler->write(Array)\n#2 /Users/matanya/Sites/indgo/vendor/monolog/monolog/src/Monolog/Logger.php(217): Monolog\\Handler\\AbstractProcessingHandler->handle(Array)\n#3 /Users/matanya/Sites/indgo/vendor/monolog/monolog/src/Monolog/Logger.php(281): Monolog\\Logger->addRecord(400, Object(ErrorException), Array)\n#4 [internal function]: Monolog\\Logger->addError(Object(ErrorException))\n#5 /Users/matanya/Sites/in in /Users/matanya/Sites/indgo/vendor/monolog/monolog/src/Monolog/Handler/StreamHandler.php on line 71

Once I used chmod to apply less stringent permissions, all went back to normal.

However, I'm not sure that it answers the OP's question, as he was getting a blank screen rather than a server error.

In the Laravel root folder chmod the storage directory to 777

Go to app/config/app.php

and set 'debug' => true,

Further to @cw24's answer  •  as of Laravel 5.4 you would instead have the following amendment in public/index.php

try {
    $response = $kernel->handle(
        $request = Illuminate\Http\Request::capture()
    );
} catch(\Exception $e) {
    echo "<pre>";
    echo $e;
    echo "</pre>";
}

And in my case, I had forgotten to fire up MySQL.
Which, by the way, is usually mysql.server start in Terminal

Just go to your app/storage/logs there logs of error available. Go to filename of today's date time and you will find latest error in your application.

OR

Open app/config/app.php and change setting

'debug' => false,

To

'debug' => true, 

OR

Go to .env file to your application and change the configuratuion

APP_LOG_LEVEL=debug

https://github.com/loic-sharma/profiler this is good example for alternative to laravel3 debug bar.

Maybe not on Laravel 4 this time, but on L5.2* I had similar issue:

I simply changed the ownership of the storage/logs directory to www-data with:

# chown -R www-data:www-data logs

PS: This is on Ubuntu 15 and with apache.

My logs directory now looks like:

drwxrwxr-x  2 www-data   www-data 4096 jaan  23 09:39 logs/