We will list here the terms that are related to the Socket.IO ecosystem.
An Adapter is a server-side component which is responsible for:
- storing the relationships between the Socket instances and the rooms
- broadcasting events to all (or a subset of) clients
There are currently two official adapters:
- the in-memory adapter, which is included by default with the Socket.IO server
- the Redis adapter, which is useful when scaling horizontally (see here)
The in-memory adapter can be extended to add support for other messaging systems, like RabbitMQ or Google Pub/Sub for example.