How to configure http_basic firewall in Symfony to return JSON in response body?

Question

By default, when you configure a http_basic firewall in Symfony, the firewall will return "401 Unauthorized" and an empty body for requests that fail.

I'd like to have it return a custom JSON (eg: {success: false, error: 401}). Is this possible?

Here's my configuration:

security:
    firewalls:
        api:
            http_basic:
                provider: myprovider

Answer 1

You need to use a custom AuthenticationEntryPoint. Create a class implementing the AuthenticationEntryPointInterface:

<?php

namespace AppBundle;

use Symfony\Component\Security\Core\Exception\AuthenticationException;
use Symfony\Component\Security\Http\EntryPoint\AuthenticationEntryPointInterface;
use Symfony\Component\HttpFoundation\Response;
use Symfony\Component\HttpFoundation\Request;

class CustomBasicAuthenticationEntryPoint implements AuthenticationEntryPointInterface {

    private $realmName;

    public function __construct($realmName) {
        $this->realmName = $realmName;
    }

    public function start(Request $request, AuthenticationException $authException = null) {
        $content = array('success' => false, 'error' => 401);

        $response = new Response();
        $response->headers->set('WWW-Authenticate', sprintf('Basic realm="%s"', $this->realmName));
        $response->headers->set('Content-Type', 'application/json');
        $response->setContent(json_encode($content))
                ->setStatusCode(401);
        return $response;
    }    
}

The class needs to be accessible as a service so add it to services.yml. Pass the realm as an argument.

custom_basic_authentication_entry_point:
         class: AppBundle\CustomBasicAuthenticationEntryPoint
         arguments: [ main ]

You can then use it in security.yml:

firewalls:
       main:
            anonymous: ~
            http_basic: ~
            entry_point: custom_basic_authentication_entry_point