Newer Version (with queuing): https:/fjbender/mwm2

This version still works fine though, but is not actively maintained anymore.

Mollie Webhook Multiplexer

What is this?

Unfortunately, Mollie can only handle one Webhook endpoint per payment transaction. This application tries to circumvent this limitation by providing a lean multiplexer, that can forward the same webhook to different applications.

You can specify the endpoints in the endpoints.neon file. See endpoints.neon.dist for an explanation of the format.

Requirements

• Some recent version of PHP (8.0 or newer should do)
• A web server that allows URL rewrites (a .htaccess file for Apache 2 is included)

Install the Application locally

• git clone https:/fjbender/mollie-webhook-multiplexer
• cd mollie-webhook-multiplexer
• composer install
• cp endoints.neon.dist endpoints.neon
• Edit endpoints.neon to your needs
• Either use docker docker-compose up or php -S localhost:8080 -t public/ to serve on http://localhost:8080 for testing

You can test the application by posting a x-www-form-urlencoded POST request with id=tr_12345 as payload to http://localhost:8080/webhooks.

When deploying in production, have the public/ directory served from the webserver.

Shop configuration

If you're using any of the Mollie default plugins, chances are that they'll set the webhook URL automatically. You'll have to hack the generation of the webhookUrl parameter, for example in Oxid 6:

    # In vendor/mollie/mollie-oxid/Application/Model/Request/Base.php
    /**
     * Return the Mollie webhook url
     *
     * @return string
     */
    protected function getWebhookUrl()
    {
        // Hack to override webhookUrl
        return 'http://mollie-multiplexer.example.com/webhooks?cl=mollieWebhook';
        // End Hack
    }

In this example, you'd need to set preserve_query: true in the endpoints file.

Limitations

• The application currently does not do any queuing of webhooks. If one forwarding endpoint breaks, the webhook is discarded for the endpoint.
• Fully synchronous: The endpoints are processed one after another. It might be that they take too long to answer, and Mollie then abandones the webhook and tries again later. This might lead to congestion. Both these point might be fixed by adding a RabbitMQ or something like that in the mix.

License

BSD (Berkeley Software Distribution) License.

Copyright (c) 2021, Florian Bender