request-context.ts36 lines · main

1	import { AsyncLocalStorage } from 'node:async_hooks';
2
3	/**
4	* Per-request context carried through async boundaries.
5	*
6	* Better Auth's `databaseHooks` (see services/auth-tenant-pool.ts) run deep
7	* inside the auth library and never receive the originating HTTP request, so
8	* they can't read the visitor IP on their own. The auth-tenant bridge in
9	* routes/auth-service.ts sets this context (IP + projectId) around the call
10	* to Better Auth's handler; the user.create hook then reads it back to
11	* capture the sign-up's raw IP + geo (control-plane SEO analytics).
12	*
13	* AsyncLocalStorage propagates the value to every promise/callback spawned
14	* within `runWithRequestContext`, so no plumbing through function signatures
15	* is required. Outside a run scope `getRequestContext()` returns undefined.
16	*/
17	export interface RequestContext {
18	/** Raw visitor IP (first value of cf-connecting-ip / x-forwarded-for). */
19	ip: string | null;
20	/** The tenant/project the request resolved to, when known. */
21	projectId?: string | null;
22	/** User-Agent header for device fingerprinting. */
23	userAgent?: string | null;
24	}
25
26	const storage = new AsyncLocalStorage<RequestContext>();
27
28	/** Run `fn` with `ctx` readable via getRequestContext() for its whole async tree. */
29	export function runWithRequestContext<T>(ctx: RequestContext, fn: () => T): T {
30	return storage.run(ctx, fn);
31	}
32
33	/** The active request context, or undefined when called outside a run scope. */
34	export function getRequestContext(): RequestContext | undefined {
35	return storage.getStore();
36	}