UrlSignerBundle

Create and validate signed URLs with a limited lifetime in Symfony.

This bundle is based on spatie/url-signer.

Installation

Make sure Composer is installed globally, as explained in the installation chapter of the Composer documentation.

Open a command console, enter your project directory and execute:

composer require tilleuls/url-signer-bundle

If you're using Symfony Flex, all configuration is already done. You can customize it in config/packages/url_signer.yaml file.

Otherwise, enable the bundle by adding it to the list of registered bundles in the config/bundles.php file of your project:

// config/bundles.php

return [
    // ...
    CoopTilleuls\UrlSignerBundle\CoopTilleulsUrlSignerBundle::class => ['all' => true],
];

Configuration

Add a signature key (as environment variable):

# config/packages/url_signer.yaml
coop_tilleuls_url_signer:
    signature_key: '%env(string:SIGNATURE_KEY)%'

In dev mode, you can use an .env file:

# .env (or .env.local)
SIGNATURE_KEY=your_signature_key

You can change the signer used to create the signature:

# config/packages/url_signer.yaml
coop_tilleuls_url_signer:
    signer: 'md5' # 'sha256' by default

The default expiration time can be changed too.

In seconds:

# config/packages/url_signer.yaml
coop_tilleuls_url_signer:
    default_expiration: 3600 # 86400 by default

With a date/time string:

# config/packages/url_signer.yaml
coop_tilleuls_url_signer:
    default_expiration: '1 day'

You can also customize the URL parameter names:

# config/packages/url_signer.yaml
coop_tilleuls_url_signer:
    expires_parameter: 'exp' # 'expires' by default
    signature_parameter: 'sign' # 'signature' by default

Usage

Generate a Signed URL

To create a temporary signed URL for a route, you first need to inject the URL signer to your service or controller:

// src/Controller/DocumentController.php
namespace App\Controller;

use CoopTilleuls\UrlSignerBundle\UrlSigner\UrlSignerInterface;

class DocumentController
{
    public function __construct(
        private UrlSignerInterface $urlSigner,
    ) {}
}

If autowiring is enabled (the default Symfony configuration) in your application, you have nothing more to do.

Otherwise, inject the url_signer.signer service in the configuration:

# config/services.yaml
services:
    App\Controller\DocumentController:
        arguments:
            $urlSigner: '@url_signer.signer'

You can now use the URL signer to generate a signed path or a signed URL:

// src/Controller/DocumentController.php
namespace App\Controller;

use Symfony\Bundle\FrameworkBundle\Controller\AbstractController;

class DocumentController extends AbstractController
{
    private function generateSignedUrl(): string
    {
        // Or $url = $this->generateUrl('secured_document', ['id' => 42], UrlGeneratorInterface::ABSOLUTE_URL);
        $url = $this->generateUrl('secured_document', ['id' => 42]);
        // Will expire after one hour.
        $expiration = (new \DateTime('now'))->add(new \DateInterval('PT1H'));
        // An integer can also be used for the expiration: it will correspond to a number of seconds. For 1 hour:
        // $expiration = 3600;

        // Not passing the second argument will use the default expiration time (86400 seconds by default).
        // return $this->urlSigner->sign($url);

        // Will return a path like this: /documents/42?expires=1611316656&signature=82f6958bd5c96fda58b7a55ade7f651fadb51e12171d58ed271e744bcc7c85c3
        // Or a URL depending on what has been signed before.
        return $this->urlSigner->sign($url, $expiration);
    }
}

Validate Signed Route Requests

To deny access to a route if the signature is not valid, add a _signed extra parameter to the route configuration:

# config/routes.yaml
secured_document:
    path: /documents/{id}
    controller: App\Controller\DocumentController::index
    defaults:
        _signed: true

If the signature is invalid (bad signature or expired URL), the request will receive a 403 response (access denied).

Custom Signer

If you need to use a specific hash algorithm for generating the signature, you can create your own signer.

Create a class extending the AbstractUrlSigner class:

// src/UrlSigner/CustomUrlSigner.php
namespace App\UrlSigner;

use CoopTilleuls\UrlSignerBundle\UrlSigner\AbstractUrlSigner;

class CustomUrlSigner extends AbstractUrlSigner
{
    public static function getName(): string
    {
        return 'custom';
    }

    protected function createSignature(string $url, string $expiration, string $signatureKey): string
    {
        return hash_hmac('algo', "{$url}::{$expiration}", $signatureKey);
    }
}

If autoconfiguring is enabled (the default Symfony configuration) in your application, you are done.

Otherwise, register and tag your service:

# config/services.yaml
services:
    App\UrlSigner\CustomUrlSigner:
        # You don't need to specify the arguments
        tags: ['url_signer.signer']

You can now use your custom signer:

# config/packages/url_signer.yaml
coop_tilleuls_url_signer:
    signer: 'custom'

Credits

Created by Alan Poulain for Les-Tilleuls.coop.