Stateful implementation of the user session.
npm install @thermopylae/lib.user-session
This is a simple example of how this package can be used.
First, you need to implement storage for user sessions. In this example we will build an in-memory storage, although it's recommended to implement a persistent storage (e.g. by using Redis).
// storage.ts
import type { Seconds } from '@thermopylae/core.declarations';
import {
PolicyBasedCache,
AbsoluteExpirationPolicyArgumentsBundle,
BucketGarbageCollector,
EsMapCacheBackend,
ProactiveExpirationPolicy,
CacheEvent
} from '@thermopylae/lib.cache';
import type { SessionId, DeviceBase } from '@thermopylae/lib.user-session.commons';
import type { UserSessionMetaData, UserSessionsStorage } from '@thermopylae/lib.user-session';
class InMemoryUserSessionStorage implements UserSessionsStorage<DeviceBase, string> {
private readonly cache: PolicyBasedCache<string, UserSessionMetaData<DeviceBase, string>, AbsoluteExpirationPolicyArgumentsBundle>;
private readonly userSessions: Map<string, Set<string>>;
public constructor() {
const backend = new EsMapCacheBackend<string, UserSessionMetaData<DeviceBase, string>>();
const policies = [new ProactiveExpirationPolicy<string, UserSessionMetaData<DeviceBase, string>>(new BucketGarbageCollector())];
this.cache = new PolicyBasedCache(backend, policies);
this.userSessions = new Map<string, Set<string>>();
this.cache.on(CacheEvent.DELETE, (sessionIdKey) => {
const [subject, sessionId] = InMemoryUserSessionStorage.decodeSessionIdKey(sessionIdKey);
const sessions = this.userSessions.get(subject)!;
sessions.delete(sessionId);
if (sessions.size === 0) {
this.userSessions.delete(subject);
}
});
}
public async insert(subject: string, sessionId: SessionId, metaData: UserSessionMetaData<DeviceBase, string>, ttl: Seconds): Promise<void> {
let sessions = this.userSessions.get(subject);
if (sessions == null) {
sessions = new Set<string>();
this.userSessions.set(subject, sessions);
}
sessions.add(sessionId);
this.cache.set(InMemoryUserSessionStorage.sessionIdKey(subject, sessionId), metaData, { expiresAfter: ttl });
}
public async read(subject: string, sessionId: SessionId): Promise<UserSessionMetaData<DeviceBase, string> | undefined> {
return this.cache.get(InMemoryUserSessionStorage.sessionIdKey(subject, sessionId));
}
public async readAll(subject: string): Promise<ReadonlyMap<SessionId, Readonly<UserSessionMetaData<DeviceBase, string>>>> {
const sessions = this.userSessions.get(subject);
if (sessions == null) {
return new Map();
}
const sessionsMetaData = new Map<SessionId, UserSessionMetaData<DeviceBase, string>>();
for (const sessionId of sessions) {
sessionsMetaData.set(sessionId, this.cache.get(InMemoryUserSessionStorage.sessionIdKey(subject, sessionId))!);
}
return sessionsMetaData;
}
public async updateAccessedAt(subject: string, sessionId: SessionId, metaData: UserSessionMetaData<DeviceBase, string>): Promise<void> {
this.cache.set(InMemoryUserSessionStorage.sessionIdKey(subject, sessionId), metaData);
}
public async delete(subject: string, sessionId: SessionId): Promise<void> {
this.cache.del(InMemoryUserSessionStorage.sessionIdKey(subject, sessionId));
}
public async deleteAll(subject: string): Promise<number> {
const sessions = Array.from(this.userSessions.get(subject) || new Set<string>());
for (const sessionId of sessions) {
this.cache.del(InMemoryUserSessionStorage.sessionIdKey(subject, sessionId));
}
return sessions.length;
}
private static sessionIdKey(subject: string, sessionId: SessionId): string {
return `${subject}:${sessionId}`;
}
private static decodeSessionIdKey(sessionIdKey: string): [string, SessionId] {
return sessionIdKey.split(':') as [string, SessionId];
}
}
export { InMemoryUserSessionStorage };
After that, we can create our UserSessionManager instance and manage user sessions.
// session.ts
import { UserSessionManager } from '@thermopylae/lib.user-session';
import { InMemoryUserSessionStorage } from './storage';
const manager = new UserSessionManager({
idLength: 24,
sessionTtl: 86_400, // 24h
timeouts: {
idle: 1_800, // 30 min
renewal: 43_200, // 12h
oldSessionAvailabilityAfterRenewal: 5 // 5 seconds
},
storage: new InMemoryUserSessionStorage(),
renewSessionHooks: {
onRenewMadeAlreadyFromCurrentProcess(sessionId) {
console.warn(
`Can't renew session '${UserSessionManager.hash(sessionId)}', because it was renewed already. Renew has been made from this NodeJS process.`
);
},
onRenewMadeAlreadyFromAnotherProcess(sessionId) {
console.warn(
`Can't renew session '${UserSessionManager.hash(sessionId)}', because it was renewed already. Renew has been made from another NodeJS process.`
);
},
onOldSessionDeleteFailure(sessionId, error) {
console.error(`Failed to delete renewed session '${UserSessionManager.hash(sessionId)}'.`, error);
}
}
});
(async function main() {
/* Create session */
let sessionId = await manager.create('uid1', { ip: '127.0.0.1' });
/* Read it */
const [sessionMetaData, renewedSessionId] = await manager.read('uid1', sessionId, { ip: '127.0.0.1' });
console.log(`Session meta data associated with session id '${sessionId}': ${JSON.stringify(sessionMetaData)}`);
if (renewedSessionId != null) {
console.warn(`User session was renewed and the new session id '${renewedSessionId}' needs to be sent to client.`);
sessionId = renewedSessionId; // the old one is no longer valid
}
/* Read all active sessions */
const activeSessions = await manager.readAll('uid1');
console.log(`User with id 'uid1' has ${activeSessions.size} active sessions.`);
/* Delete session */
await manager.delete('uid1', sessionId);
/* Delete all sessions */
const deletedSessionsNo = await manager.deleteAll('uid1');
console.info(`Deleted ${deletedSessionsNo} active sessions of user with id 'uid1'.`);
})();
API documentation is available here.
It can also be generated by issuing the following commands:
git clone git@github.com:marinrusu1997/thermopylae.git
cd thermopylae
yarn install
yarn workspace @thermopylae/lib.user-session run doc
👤 Rusu Marin
Copyright © 2021 Rusu Marin.
This project is MIT licensed.