Bitbucket - Webhook keep returning error 500 - laravel

Question

Would like to check, I am fairly new to Bitbucket's new introduced webhook where previously i was using services where Bitbucket will execute a link to my site thus triggering a deployment script.
So since the old service is going to be depreciated soon, we all migrated to webhook instead. With the same implementation, I keep getting an error 500 upon commit/push/merge and there is no way for us to see the details for the error given. At first I thought it was my server giving problem but when i call the link manually via browsers and everything was fine. The deployment script can be executed successfully so then why bitbucket's webhook keeps telling me error 500?
Subsequently I find the guide given by Bitbucket was not helpful. There is no specified call method to the url stated so is the webhook initiates a GET or POST request? previously using services initiates a POST request. Then, are there any necessary payloads i need to include into the webhook URL? None is stated. Then, if there is an error at least let me see the error so I can fix it instead of telling me error 500.
I hope someone here can help me with this issue. Below are some specification of the site.
Server : Ubuntu LEMP 14.04 x64 Laravel framework 5.0
Webhook Url: bot.example.com/bitbucket/deploy/{Site API}
Method : GET
And when the abode link is call, it reaches a controller that does
public function attemptDeploy($site_api)
{
$script = 'nohup setsid php ~/scripts/deploy.php ' . $site_api. ' > /dev/null 2>&1 &';
exec($script);
return response('Deploy running.', 200);
}
Note that when i call this link manually either form browser or console everything works perfectly except from bitbucket's webhook. How can i solve this issue?

Answer 1

I was in the same situation. Bitbucket trims the body of the response and I couldn't see the error given by my server.
I've looked into the logs storage/logs/laravel.log and saw TokenMismatchException. Webhooks being API calls they don't store cookies or sessions so CSRF from Laravel breaks.
You need to add an exception from CSRF for the bitbucket deploy route. You can add this exception in app/Http/Middleware/VerifyCsrfToken.php. For example if your link is www.your_site.com/bit_deploy you will have:
<?php
namespace App\Http\Middleware;
use Illuminate\Foundation\Http\Middleware\VerifyCsrfToken as BaseVerifier;
class VerifyCsrfToken extends BaseVerifier
{
/**
* The URIs that should be excluded from CSRF verification.
*
* #var array
*/
protected $except = [
'bit_deploy'
];
}
Hope that this helps you ... as I've lost 3 hours on this.
PS: at the time of writing this answer, bitbucket webhooks performs POST calls (not GET)