Subscriptions: Getting Started

Subscriptions allow GraphQL clients to observe specific events and receive updates from the server when those events occur.

NOTE

Much of the credit should be given to the Ruby implementation (opens new window) as they provided a great overview of how the backend should work.

Setup

Install the Pusher PHP Library (opens new window) for interacting with the Pusher HTTP API.

composer require pusher/pusher-php-server

Add the service provider to your config/app.php

'providers' => [
    \Nuwave\Lighthouse\Subscriptions\SubscriptionServiceProvider::class,
],

Pusher Webhook

Subscriptions do not expire by themselves. Unless a subscription is deleted, it will continue to broadcast events after the client has disconnected.

Using a Presence webhook will mitigate this problem. When a Pusher channel is abandoned (ie. unsubscribed), it will trigger the webhook, which will instruct Lighthouse to delete the subscription.

The webhook URL will typically be:

/graphql/subscriptions/webhook

You can add the webhook in the Pusher Dashboard. Select the type Presence.