Sync (IPFS snapshots)

Requires helia + @helia/json (optional peer dependencies — see Installation). Import from @ethereum-radio/indexer/sync/ipfs.

This is an optional, opt-in layer for bootstrapping a new client from a previously-published scan snapshot instead of re-scanning from floorBlock over RPC — useful for a widely-used contract where re-walking the full history on every first visit is wasteful. It's entirely decoupled from Cursor/createRadio: nothing in the core streaming/scanning path knows Helia exists, and nothing here touches a SpanStore directly. You call these functions explicitly, at the edges.

RadioSnapshot

interface RadioSnapshot {
	spans: Span[];
	logs: RawLog[];
}

spans is what a SpanStore needs to consider that history already scanned; logs is whatever matching logs you've accumulated app-side for that history. What you do with logs (render them, cache them elsewhere) is entirely up to you — this module has no opinion on app-level log storage.

exportSnapshot

function exportSnapshot(fs: JsonBlockstore, snapshot: RadioSnapshot): Promise<CID>;

Publishes a snapshot's spans + logs as one content-addressed IPFS object, returning the CID to pin/share. Call this after some scanning, with await cursor.getScannedSpans() plus whatever logs you've collected.

importSnapshot

function importSnapshot(fs: JsonBlockstore, cid: CID): Promise<RadioSnapshot>;

Fetches a previously-exported snapshot back. Typical use: before starting createRadio(...), import a known snapshot and seed the store with its spans (await store.save(key, snapshot.spans)) so the cursor already considers that history scanned — createRadio/radio() then only need to fill the remaining gap up to the tip.

JsonBlockstore

interface JsonBlockstore {
	add(value: unknown): Promise<CID>;
	get<T = unknown>(cid: CID): Promise<T>;
}

A small structural interface — not a hard dependency on Helia's own types — satisfied by json(helia) from @helia/json:

import {createHelia} from 'helia';
import {json} from '@helia/json';
import {exportSnapshot, importSnapshot} from '@ethereum-radio/indexer/sync/ipfs';

const helia = await createHelia();
const fs = json(helia);

const cid = await exportSnapshot(fs, {spans, logs});
// ...later, on a different client:
const snapshot = await importSnapshot(fs, cid);