Redis Store

The RedisStore is a Redis-backed implementation of the Store interface that provides per-session, distributed key–value storage using Redisson’s RMap. Each connected client receives a dedicated Redis map identified by its sessionId, allowing session data to be accessed consistently across multiple nodes in a clustered environment.

Key characteristics

• Distributed per-session storage — session data is stored in Redis, not local memory

• Cross-node visibility — values are accessible across all servers sharing the same Redis instance

• Persistent by backend configuration — data survives JVM/node restarts while Redis is running

• Dedicated keyspace per session — each session creates its own RMap using the session identifier

• Pluggable with any EventStore — can pair with Kafka, Redis Streams, Hazelcast, NATS, etc.

How it works

• set(key, value) writes a value into a Redis map for this session

• get(key) retrieves the value from Redis

• has(key) checks key presence in the distributed map

• del(key) removes a single key from the map

• destroy() deletes the entire session map, typically when the client disconnects

Advantages

👍 Session data is available to all nodes — supports horizontal scaling 👍 Survives server restarts as long as Redis is running 👍 Aligns naturally with distributed event propagation setups 👍 Enables mixing storage with any EventStore backend (e.g., RedisStore + KafkaEventStore, RedisStore + HazelcastRingBufferEventStore)

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Summary

RedisStore provides distributed, per-session storage backed by Redis, making session data visible and persistent across multiple socketio4j nodes. Ideal for clustered deployments when session state must be shared.