feat: upgrade to Mercure 1.0 alpha 3

[dunglas]

Upgrades github.com/dunglas/mercure and github.com/dunglas/mercure/caddy from v0.24.2 to v1.0.0-alpha.3, and adapts the integration to the protocol changes of draft-dunglas-mercure-08.

mercure_publish()

The hub validates updates before dispatching them, so the function now distinguishes the caller's mistakes from a failed publication:

• a ValueError carrying the reason for a topic addressing the reserved /.well-known/mercure namespace or equal to *, an $id starting with # or equal to earliest, a $type equal to mercure, control characters, invalid UTF-8 $data, or no topic at all;
• a RuntimeException with the message of the hub when the dispatch fails.

The negative values of $retry are also rejected, as the protocol only allows digits in that field.

An enum in frankenphp.h replaces the status codes go_mercure_publish() returned as bare integers. On the way, an array of topics that cannot be converted no longer reports No Mercure hub configured.

Hot reloading

The subscribe query parameter of the protocol is match, so $_SERVER['FRANKENPHP_HOT_RELOAD'] advertises /.well-known/mercure?match=<topic>. The topic parameter it replaces is only honored by a hub built with the deprecated_topic tag, which FrankenPHP doesn't set.

Hub configuration

Setting publisher_jwt or subscriber_jwt without protocol_version_compatibility is a configuration error now, because that mode also drops the required exp, the audience check, the at+jwt check and the issuer check. The keys are bound to a trusted issuer instead:

mercure {
	issuer {$MERCURE_TRUSTED_ISSUERS:https://localhost} {
		publisher {
			jwt {env.MERCURE_PUBLISHER_JWT_KEY} {env.MERCURE_PUBLISHER_JWT_ALG}
		}
		subscriber {
			jwt {env.MERCURE_SUBSCRIBER_JWT_KEY} {env.MERCURE_SUBSCRIBER_JWT_ALG}
		}
	}
}

php-server --mercure and the sample Caddyfile follow, and the access tokens using the 0.x mercure claim are rejected: FrankenPHP is built without the compatibility tags of the hub.

Notes

• The translations of docs/mercure.md still describe the 0.x configuration.
• The Symfony Mercure example needs symfony/mercure 0.8 for ProtocolVersion::V1, unreleased as this hub is still an alpha.