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Glossary

TL;DR The lookup reference for the terms that recur across smocket's docs. Each doc links here on first use and never redefines a term. Most entries describe socket.io itself; the few smocket-specific terms that recur are anchored here too, each linking to the owning doc where the behaviour is decided.

Terms are listed in dependency order: later entries lean on earlier ones.

room​

A server-side label a socket can join and leave. A broadcast can target a room to reach exactly its current members, and one socket may belong to many rooms at once.

namespace​

A named channel (a path such as / or /admin) with its own sockets, rooms, and handlers. Isolation is complete: a broadcast on one namespace never reaches a socket on another.

adapter​

The per-namespace component that stores room membership and resolves which sockets a broadcast targets. The default holds this in memory; the Redis adapter replaces it to span multiple servers.

ack​

Short for acknowledgement. A callback passed as the last argument to emit; the receiver calls it to send a value back, turning a single event into a request/response round trip.

handshake​

The initial exchange when a client connects, carrying connection metadata such as headers, query, and auth. The server reads it as socket.handshake.

broadcast​

Sending one event to many sockets at once instead of to a single peer. io.emit reaches every socket on the namespace; a room or an except narrows that set.

sid​

A socket's session id: the unique identifier assigned on connect and held in socket.id. Each socket also auto-joins a room named after its own sid, which is how a broadcast can address a single socket.

nsp​

socket.io's own short name for a namespace, used as a property (socket.nsp) and returned by io.of(name). See namespace.

broadcast operator​

The object returned by io.to(room), socket.broadcast, socket.except(room), and their siblings. It holds the target and excluded room sets and exposes emit, so every broadcast form is one mechanism built with different sets. It also carries to / in / except / timeout, each returning a further operator over the merged sets, which is what lets a broadcast be narrowed in any order.

origin registry​

smocket-specific. The in-memory map from a normalized URL origin to the Server registered there. new Server(url) adds itself to it, and connect(url) resolves a client's target through it, standing in for the network a real client would reach over. Decided in 0003 and 0014.