How to add a custom exception on symfony2

Question

I am new to Symfony(using version 2.2) and trying to add a custom exception listener. I have read the following links but cannot get it to work.

• Overriding Symfony 2 exceptions?
• Symfony2 Custom Error Exception Listener - Rendering templates or passing to a controller

What I'm trying to do is to create a custom Error Exception Listener and use it from my controllers and services like this,

throw new jsonErrorException('invalid_params');

to display json twig template like this.(I'm developing a background program for my native smartphone applications)

{"status": "error", "message": "invalid_params"}

I have registered my CustomEventListener to my src/My/Bundle/Resources/config/services.yml and created a custom exception class as shown on following link( Overriding Symfony 2 exceptions? ) but I get the error

symfony exceptions must be valid objects derived from the exception base class

Am I doing something wrong here? Thanks.

Answer 1

You can create custom exception the "symfony way" let's look at how exception or created in symfony:

first create your customExceptionInterface

namespace My\SymfonyBundle\Exception;
/**
 * Interface for my bundle exceptions.
 */
interface MySymfonyBundleExceptionInterface
{
}

And create your jsonErrorException

namespace My\SymfonyBundle\Exception;

class HttpException extends \Exception implements MySymfonyBundleExceptionInterface
{
}

Don't hesitate to browse symfony's exceptions code examples on github

Answer 2

I recently implemented a custom exception in my Symfony2 service in the following manner:

MemberAlreadyExistsException.php

<?php

namespace Aalaap\MyAppBundle\Services\Membership;

class MemberAlreadyExistsException extends \Exception
{

}

Subscriber.php

<?php

namespace Aalaap\MyAppBundle\Services\Membership;
...
throw new MemberAlreadyExistsException(
    'The member you are trying to subscribe already'
    . ' exists in this list.'
);
...

Answer 3

您必须扩展Exception类，或者至少扩展Symfony的内部异常类

Answer 4

I just had to add \\ and the global scope worked in a Symfony service

namespace App\CoreBundle\Service;

class CurrencyExchange
{
    const RATES_XML = 'https://www.ecb.europa.eu/stats/eurofxref/eurofxref-daily.xml?849b4b329863b2d60bfd0de486e423c9';

    const RATES_XML_PATH = 'uploads/ecb_currencies.xml';

    /** @var array $rates */
    private $rates;

    public function __construct()
    {
        if (!is_file(self::RATES_XML_PATH)) {
            throw new \Exception('XML '.self::RATES_XML_PATH.' does not exists.');
        }

        if (1 > filesize(self::RATES_XML_PATH)) {
            throw new \Exception('XML '.self::RATES_XML_PATH.' is empty.');
        }