Commit 53bf627

Webhook

Scaleway delivers email events through [Scaleway Topics and Events][topics-and-events],

which signs each message instead of sharing a secret. That's why the `secret`

option is not needed for this provider.

The bridge verifies the signature with the certificate referenced by the

`SigningCertURL` field of the message, after checking that the Scaleway

certificate authority bundled with the bridge issued it. Fetching the

certificate requires the [HttpClient component][http-client]. In Symfony

applications, the certificate is cached in the `cache.app` pool.

The first time Scaleway calls the endpoint, it sends a subscription confirmation

message and the bridge confirms it automatically. That message contains no

email event, so your application responds to it with an HTTP 406 status code.

This is expected: the subscription is confirmed by the request the bridge makes

to Scaleway, not by that response.

[topics-and-events]: https://www.scaleway.com/en/docs/topics-and-events/reference-content/verifying-webhooks/

[http-client]: https://symfony.com/http-client