Routing

Slack routing is independent of the message content. It is selected via NotificationManager::route(), NotificationManager::routes(), or a notifiable's routeNotificationForSlack() method.

Four route styles

Route	Example	Notes
Named webhook	`SlackRoute::webhookNamed('monitoring')`	Recommended for queued delivery; no URL secret in the route object.
Direct webhook	`SlackRoute::webhook($url)`	Approved HTTPS Slack URL; the URL is a secret.
Web API	`SlackRoute::api('C0123456789', '_optional_token_')`	Supply the token here otherwise the engine will get it from the extension configuration.
url as string	`SlackRoute::fromString($url)` or `SlackRoute::fromString(webhook:_name_)`	The engine will try to guess whether it's an Incoming webhook and an API

Named webhooks

$manager->route(
    'slack',
    SlackRoute::webhookNamed('security')
)->notify(new SecurityAlert());

// Shorthand accepted by SlackRoute::fromString():
$manager->route('slack', 'webhook:security')
    ->notify(new SecurityAlert());

The alias must exist in webhooks inside $GLOBALS['TYPO3_CONF_VARS']['EXTENSIONS']['notifications_slack']. If it does not exist, delivery fails with a configuration exception.

Direct webhook

$manager->route('slack', SlackRoute::webhook($webhookUrl))
    ->notify(new SecurityAlert());

The validator permits HTTPS URLs with a Slack or GovSlack webhook host and a /services/.../.../... path. A webhook URL is a credential. Avoid serializing it into Messenger jobs; use a named webhook instead.

Slack Web API

$manager->route('slack', SlackRoute::api('C0123456789', '_optional_token_'))
    ->notify(new SecurityAlert());

// An ID string is also accepted:
$manager->route('slack', 'C0123456789')
    ->notify(new SecurityAlert());

SlackRoute::api() accepts a supported Slack conversation/user ID prefix (C, D, G, U or W) followed by uppercase letters/digits. The Slack API ultimately determines whether that ID can receive messages and whether the app has access.

Multiple recipients

The core notification dispatcher can send one notification to a collection of notifiable objects, each returning a different Slack route:

$manager->send(
    [$monitoringRecipient, $securityRecipient],
    new SecurityAlert(),
);

SlackMessage intentionally does not accept a channel or token field: routing and credentials belong to the channel and transport.