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Add public AppView actor lookup for landing handle input
author
Jeremy Herve
date
(Jun 9, 2026, 12:57 PM +0200)
commit
ce974088
ce97408854b347ed9f0131e4eec495e8ccc0b2a8
parent
631c4fab
631c4fab9c237d7c0af565e4ebf430b94408ca9d
+110
+59
src/lib/landing/actor-lookup.test.ts
+59
src/lib/landing/actor-lookup.test.ts
···
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import { describe, expect, it, vi } from 'vitest';
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import { lookupActor } from './actor-lookup';
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const ok = ( body: unknown ) =>
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( { ok: true, json: async () => body } ) as unknown as Response;
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const notOk = () => ( { ok: false, json: async () => ( {} ) } ) as unknown as Response;
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describe( 'lookupActor', () => {
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it( 'returns a preview for a resolvable handle', async () => {
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const fetchImpl = vi.fn().mockResolvedValue(
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ok( {
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did: 'did:plc:abc',
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handle: 'alice.bsky.social',
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displayName: 'Alice Rivers',
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avatar: 'https://cdn.example/a.jpg',
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} )
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);
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const preview = await lookupActor( '@Alice.bsky.social', fetchImpl as unknown as typeof fetch );
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expect( preview ).toEqual( {
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did: 'did:plc:abc',
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handle: 'alice.bsky.social',
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displayName: 'Alice Rivers',
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avatar: 'https://cdn.example/a.jpg',
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} );
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expect( fetchImpl ).toHaveBeenCalledWith(
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'https://public.api.bsky.app/xrpc/app.bsky.actor.getProfile?actor=alice.bsky.social'
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);
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} );
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it( 'passes a DID through untouched', async () => {
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const fetchImpl = vi.fn().mockResolvedValue( ok( { did: 'did:plc:xyz', handle: 'x.test' } ) );
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await lookupActor( 'did:plc:xyz', fetchImpl as unknown as typeof fetch );
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expect( fetchImpl ).toHaveBeenCalledWith(
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'https://public.api.bsky.app/xrpc/app.bsky.actor.getProfile?actor=did%3Aplc%3Axyz'
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);
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} );
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it( 'returns null without fetching for syntactically invalid input', async () => {
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const fetchImpl = vi.fn();
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expect( await lookupActor( 'notahandle', fetchImpl as unknown as typeof fetch ) ).toBeNull();
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expect( await lookupActor( ' ', fetchImpl as unknown as typeof fetch ) ).toBeNull();
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expect( fetchImpl ).not.toHaveBeenCalled();
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} );
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it( 'returns null on a non-ok response', async () => {
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const fetchImpl = vi.fn().mockResolvedValue( notOk() );
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expect( await lookupActor( 'ghost.bsky.social', fetchImpl as unknown as typeof fetch ) ).toBeNull();
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} );
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it( 'returns null when the network throws', async () => {
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const fetchImpl = vi.fn().mockRejectedValue( new Error( 'offline' ) );
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expect( await lookupActor( 'alice.bsky.social', fetchImpl as unknown as typeof fetch ) ).toBeNull();
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} );
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it( 'returns null when the body has no did', async () => {
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const fetchImpl = vi.fn().mockResolvedValue( ok( { handle: 'x.test' } ) );
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expect( await lookupActor( 'x.test', fetchImpl as unknown as typeof fetch ) ).toBeNull();
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} );
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} );
+51
src/lib/landing/actor-lookup.ts
+51
src/lib/landing/actor-lookup.ts
···
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/**
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* Live "find me on the network" lookup for the landing handle input.
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*
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* Calls the PUBLIC Bluesky AppView UNAUTHENTICATED (no OAuth, no secrets) purely to
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* show the writer their own avatar + name as confirmation before sign-in. This runs
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* client-side in a React island, the host is a fixed constant, and `actor` is the only
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* user input — validated by `isValidHandleOrDid` and URL-encoded — so it can't be
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* coerced into a different host or path. Never throws: any failure resolves to `null`
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* ("no preview"), because submission must never depend on this lookup succeeding.
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*/
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import { isValidHandleOrDid, normalizeHandle } from '../auth/config';
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const APPVIEW = 'https://public.api.bsky.app';
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export interface ActorPreview {
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did: string;
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handle: string;
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displayName: string | null;
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avatar: string | null;
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}
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export async function lookupActor(
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input: string,
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fetchImpl: typeof fetch = fetch
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): Promise< ActorPreview | null > {
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const value = input.trim();
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if ( ! isValidHandleOrDid( value ) ) {
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return null;
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}
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const actor = value.startsWith( 'did:' ) ? value : normalizeHandle( value );
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try {
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const res = await fetchImpl(
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`${ APPVIEW }/xrpc/app.bsky.actor.getProfile?actor=${ encodeURIComponent( actor ) }`
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);
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if ( ! res.ok ) {
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return null;
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}
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const data = ( await res.json() ) as Partial< ActorPreview >;
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if ( ! data?.did ) {
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return null;
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}
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return {
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did: data.did,
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handle: data.handle ?? actor,
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displayName: data.displayName ?? null,
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avatar: data.avatar ?? null,
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};
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} catch {
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return null;
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}
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}