Bun+ElysiaJS+openid-clientでGitLab SSO用のOIDCクライアントを実装する

export interface OIDCClientSession {
  /** Session ID */
  sessionId: string;
  /** Session expired at (Unixtime, ms) */
  sessionExpiredAt: number;
  /** Session refreshed at (Unixtime, ms) */
  sessionRefreshedAt: number;
  /** OIDC Code Verifier for PKCE */
  codeVerifier?: string;
  /** OIDC Refresh Token */
  refreshToken?: string;
  /** OIDC sub Claim */
  sub?: string;
}

export interface OIDCClientOptions {
  /** OpenID Provider @example "https://gitlab.com" */
  issuerUrl: string;
  /** Client ID */
  clientId: string;
  /** Client secret */
  clientSecret: string;
  /** Application base url @example "https://example.com" */
  baseUrl: string;
  /**
    Path to redirect after callback is complete (use with baseUrl)
    @default "/"
    @example "/path/to/app"
  */
  completedPath?: string;
  /** Database file path @default "sessions.db" @example "/path/to/sessions.db" */
  dbFile?: string;
  /** Path prefix @default "/auth" */
  pathPrefix?: string;
  /** Login path (GET) @default "/login" */
  loginPath?: string;
  /** Callback path (GET) @default "/callback" */
  callbackPath?: string;
  /** Login expiration (ms) @default 600000 (10 minutes) */
  loginExpiration?: number;
  /** Refresh expiration (ms) @default 2592000000 (30 days) */
  refreshExpiration?: number;
  /** Refresh interval (ms) @default 1800000 (30 minutes) */
  refreshInterval?: number;
  /** Scope of onBeforeHandle @default "scoped" */
  onBeforeScope?: LifeCycleType;
}

let sessions: Collection<OIDCClientSession>;
const db = new loki(dbFile, {
  autoload: true,
  autoloadCallback: () => {
    sessions = db.getCollection<OIDCClientSession>("sessions");
    if (!sessions) {
      sessions = db.addCollection<OIDCClientSession>("sessions", {
        indices: ["sessionId", "sessionExpiredAt"],
        unique: ["sessionId"],
      });
    }
  },
  autosave: true,
  autosaveInterval: 10000,
  autosaveCallback: () => {
    sessions
      .chain()
      .find({ sessionExpiredAt: { $lt: Date.now() } })
      .remove();
  },
});