Class InMemorySessionStore

Built-in in-memory session store using a Map.

Suitable for single-instance deployments. For horizontal scaling, implement the SessionStore interface with a shared backend.

Responsibilities:

Create, get, close, and query sessions
Enforce capacity limits
Track statistics (created, peak, by transport type)
Broadcast notifications to all connected clients

Does NOT manage timers or background tasks.

Example

const store = new InMemorySessionStore(100);

const session = store.create({ transportType: 'http', transport, mcpSession });
const found = store.get(session.id);
store.broadcastToolListChanged();
await store.close(session.id, SESSION_CLOSE_REASONS.CLIENT_DISCONNECT);

Implements

SessionStore

Index

Constructors

constructor

new InMemorySessionStore(maxSessions: number): InMemorySessionStore
Parameters
- maxSessions: number
Returns InMemorySessionStore
- Defined in src/server/session/in-memory-store.ts:92

Accessors

size

get size(): number
Number of active sessions

Returns number
Implementation of SessionStore.size
- Defined in src/server/session/in-memory-store.ts:98

stats

get stats(): SessionStats
Current statistics

Returns SessionStats
Implementation of SessionStore.stats
- Defined in src/server/session/in-memory-store.ts:102

Methods

broadcastPromptListChanged

broadcastPromptListChanged(): void
Broadcasts prompt list changed notification to all active sessions

Returns void
Implementation of SessionStore.broadcastPromptListChanged
- Defined in src/server/session/in-memory-store.ts:312

broadcastResourceListChanged

broadcastResourceListChanged(): void
Broadcasts resource list changed notification to all active sessions

Returns void
Implementation of SessionStore.broadcastResourceListChanged
- Defined in src/server/session/in-memory-store.ts:308

broadcastResourceUpdated

broadcastResourceUpdated(uri: string): void
Sends a resource updated notification to sessions subscribed to the given URI.

Unlike list-changed broadcasts (sent to all sessions), this only notifies sessions that have subscribed to the specific resource URI via resources/subscribe.
Parameters
- uri: string
Returns void
Implementation of SessionStore.broadcastResourceUpdated
- Defined in src/server/session/in-memory-store.ts:316

broadcastToolListChanged

broadcastToolListChanged(): void
Broadcasts tool list changed notification to all active sessions.

Returns void
Implementation of SessionStore.broadcastToolListChanged
- Defined in src/server/session/in-memory-store.ts:304

create

create(options: CreateSessionOptions): Session | undefined
Creates and registers a new session.

Capacity check and insertion are synchronous (no await between them), which is safe in Node.js single-threaded event loop. Do NOT introduce any async operations between hasCapacity() and sessions.set().
Parameters
- options: CreateSessionOptions
  Session creation options
Returns Session | undefined
The created session, or undefined if at max capacity or shutting down
Implementation of SessionStore.create
- Defined in src/server/session/in-memory-store.ts:128

filter

filter(predicate: (session: ReadonlySession) => boolean): Readonly<Session>[]
Finds sessions matching a predicate.
Parameters
- predicate: (session: ReadonlySession) => boolean
Returns Readonly<Session>[]
Implementation of SessionStore.filter
- Defined in src/server/session/in-memory-store.ts:280

forEach

forEach(callback: (session: ReadonlySession, sessionId: string) => void): void
Iterates over all active sessions.
Parameters
- callback: (session: ReadonlySession, sessionId: string) => void
Returns void
Implementation of SessionStore.forEach
- Defined in src/server/session/in-memory-store.ts:271

get

get(sessionId: string): Session | undefined
Gets an active session by ID. Does NOT update activity time (use touch() for that).
Parameters
- sessionId: string
Returns Session | undefined
Implementation of SessionStore.get
- Defined in src/server/session/in-memory-store.ts:159

getByTransportType

getByTransportType(type: TransportType): Readonly<Session>[]
Gets all sessions of a specific transport type.
Parameters
- type: TransportType
Returns Readonly<Session>[]
Implementation of SessionStore.getByTransportType
- Defined in src/server/session/in-memory-store.ts:293

has

has(sessionId: string): boolean
Checks if a session exists and is active.
Parameters
- sessionId: string
Returns boolean
Implementation of SessionStore.has
- Defined in src/server/session/in-memory-store.ts:170

hasCapacity

hasCapacity(): boolean
Checks if there's capacity for new sessions.

Returns boolean
Implementation of SessionStore.hasCapacity
- Defined in src/server/session/in-memory-store.ts:195

markShuttingDown

markShuttingDown(): void
Marks the store as shutting down (rejects new sessions).

Returns void
Implementation of SessionStore.markShuttingDown
- Defined in src/server/session/in-memory-store.ts:260

remove

remove(sessionId: string, reason: SessionCloseReason): Session | undefined
Removes a session from the store and updates statistics.

Pure data operation — does NOT close transport or dispose MCP session. The caller (SessionManager) is responsible for I/O teardown.
Parameters
- sessionId: string
  Session identifier
- reason: SessionCloseReason
  Reason for closure (tracked in stats)
Returns Session | undefined
The removed session, or undefined if not found
Implementation of SessionStore.remove
- Defined in src/server/session/in-memory-store.ts:213

removeAll

removeAll(): Session[]
Removes all sessions from the store during shutdown. Returns the removed sessions for the caller to handle I/O teardown.

Returns Session[]
Implementation of SessionStore.removeAll
- Defined in src/server/session/in-memory-store.ts:239

touch

touch(sessionId: string): boolean
Updates the last activity time for a session. Also resets missed heartbeat count.
Parameters
- sessionId: string
Returns boolean
Implementation of SessionStore.touch
- Defined in src/server/session/in-memory-store.ts:179

Class InMemorySessionStore

Example

Implements

Index

Constructors

Accessors

Methods

Constructors

constructor

Parameters

Returns InMemorySessionStore

Accessors

size

Returns number

stats

Returns SessionStats

Methods

broadcastPromptListChanged

Returns void

broadcastResourceListChanged

Returns void

broadcastResourceUpdated

Parameters

Returns void

broadcastToolListChanged

Returns void

create

Parameters

Returns Session | undefined

filter

Parameters

Returns Readonly<Session>[]

forEach

Parameters

Returns void

get

Parameters

Returns Session | undefined

getByTransportType

Parameters

Returns Readonly<Session>[]

has

Parameters

Returns boolean

hasCapacity

Returns boolean

markShuttingDown

Returns void

remove

Parameters

Returns Session | undefined

removeAll

Returns Session[]

touch

Parameters

Returns boolean

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