Merge branch 'paginated-list' into 'main'

Paginate list events (kind 3, 10000)

See merge request soapbox-pub/ditto!343

src/controllers/api/mutes.ts

@@ -16,7 +16,7 @@ const mutesController: AppController = async (c) => {
 
   if (event10000) {
     const pubkeys = getTagSet(event10000.tags, 'p');
-    return renderAccounts(c, [...pubkeys].reverse());
+    return renderAccounts(c, [...pubkeys]);
   } else {
     return c.json([]);
   }

src/utils/api.ts

@@ -138,8 +138,8 @@ async function parseBody(req: Request): Promise<unknown> {
 
 /** Schema to parse pagination query params. */
 const paginationSchema = z.object({
-  since: z.coerce.number().optional().catch(undefined),
+  since: z.coerce.number().nonnegative().optional().catch(undefined),
-  until: z.coerce.number().optional().catch(undefined),
+  until: z.coerce.number().nonnegative().optional().catch(undefined),
   limit: z.coerce.number().catch(20).transform((value) => Math.min(Math.max(value, 0), 40)),
 });
 
@@ -179,6 +179,47 @@ function paginated(c: AppContext, events: NostrEvent[], entities: (Entity | unde
   return c.json(results, 200, headers);
 }
 
+/** Query params for paginating a list. */
+const listPaginationSchema = z.object({
+  offset: z.coerce.number().nonnegative().catch(0),
+  limit: z.coerce.number().catch(20).transform((value) => Math.min(Math.max(value, 0), 40)),
+});
+
+/** Build HTTP Link header for paginating Nostr lists. */
+function buildListLinkHeader(url: string, params: { offset: number; limit: number }): string | undefined {
+  const { origin } = Conf.url;
+  const { pathname, search } = new URL(url);
+  const { offset, limit } = params;
+  const next = new URL(pathname + search, origin);
+  const prev = new URL(pathname + search, origin);
+
+  next.searchParams.set('offset', String(offset + limit));
+  prev.searchParams.set('offset', String(Math.max(offset - limit, 0)));
+
+  next.searchParams.set('limit', String(limit));
+  prev.searchParams.set('limit', String(limit));
+
+  return `<${next}>; rel="next", <${prev}>; rel="prev"`;
+}
+
+/** paginate a list of tags. */
+function paginatedList(
+  c: AppContext,
+  params: { offset: number; limit: number },
+  entities: (Entity | undefined)[],
+  headers: HeaderRecord = {},
+) {
+  const link = buildListLinkHeader(c.req.url, params);
+
+  if (link) {
+    headers.link = link;
+  }
+
+  // Filter out undefined entities.
+  const results = entities.filter((entity): entity is Entity => Boolean(entity));
+  return c.json(results, 200, headers);
+}
+
 /** JSON-LD context. */
 type LDContext = (string | Record<string, string | Record<string, string>>)[];
 
@@ -209,8 +250,10 @@ export {
   createAdminEvent,
   createEvent,
   type EventStub,
+  listPaginationSchema,
   localRequest,
   paginated,
+  paginatedList,
   type PaginationParams,
   paginationSchema,
   parseBody,

src/views.ts

@@ -4,7 +4,7 @@ import { AppContext } from '@/app.ts';
 import { Storages } from '@/storages.ts';
 import { renderAccount } from '@/views/mastodon/accounts.ts';
 import { renderStatus } from '@/views/mastodon/statuses.ts';
-import { paginated, paginationSchema } from '@/utils/api.ts';
+import { listPaginationSchema, paginated, paginatedList, paginationSchema } from '@/utils/api.ts';
 import { hydrateEvents } from '@/storages/hydrate.ts';
 import { accountFromPubkey } from '@/views/mastodon/accounts.ts';
 
@@ -42,12 +42,14 @@ async function renderEventAccounts(c: AppContext, filters: NostrFilter[], opts?:
   return paginated(c, events, accounts);
 }
 
-async function renderAccounts(c: AppContext, authors: string[], signal = AbortSignal.timeout(1000)) {
+async function renderAccounts(c: AppContext, pubkeys: string[]) {
-  const { since, until, limit } = paginationSchema.parse(c.req.query());
+  const { offset, limit } = listPaginationSchema.parse(c.req.query());
+  const authors = pubkeys.reverse().slice(offset, offset + limit);
 
   const store = await Storages.db();
+  const signal = c.req.raw.signal;
 
-  const events = await store.query([{ kinds: [0], authors, since, until, limit }], { signal })
+  const events = await store.query([{ kinds: [0], authors }], { signal })
     .then((events) => hydrateEvents({ events, store, signal }));
 
   const accounts = await Promise.all(
@@ -61,7 +63,7 @@ async function renderAccounts(c: AppContext, authors: string[], signal = AbortSi
     }),
   );
 
-  return paginated(c, events, accounts);
+  return paginatedList(c, { offset, limit }, accounts);
 }
 
 /** Render statuses by event IDs. */