@dasl/tile-car-reader

Read DASL tiles from a CAR-based .tile file.

The reader indexes a tile once on open(), then resolves request paths to their HTTP headers and a stream over just that resource's bytes — without reading the whole file into memory. Path resolution ignores query strings and hashes, so /img/cat.jpg?v=2 resolves the same as /img/cat.jpg.

Node.js only — it opens the file and hands back node:fs read streams.

Install

npm install @dasl/tile-car-reader

Usage

import CarTileReader from '@dasl/tile-car-reader';

const ctr = new CarTileReader('/path/to/a/car-based.tile');
await ctr.open();

const nf = ctr.resolvePath('/not/exists');
// nf.ok === false, nf.status === 404

const root = ctr.resolvePath('/');
// root.ok === true, root.status === 200
sendHeaders(root.headers);            // { 'content-type': 'text/html' }
root.createReadStream().pipe(res);    // stream the bytes

ctr.close();

API

new CarTileReader(path)

path is the location of the .tile file on disk.

await reader.open()

Reads the header and builds the resource index. Must be called before resolvePath.

reader.meta

The tile's MASL metadata (a StoredMasl), with the CAR bookkeeping (version, roots) stripped.

reader.resolvePath(path)

Returns either:

• hit — { ok: true, status: 200, statusText, headers, createReadStream() }, where createReadStream() streams exactly that resource's bytes; or
• miss — { ok: false, status: 404, statusText } (no stream).

The CarResolveResult / CarResolveOk / CarResolveError types are exported for TypeScript consumers.

reader.close()

Closes the underlying file handle. Safe to call more than once.

Part of DASL tiles

• @dasl/tiles — meta-package re-exporting the whole toolkit
• @dasl/tile-loader — load tiles in the browser
• @dasl/tile-server — the browser tile-loading server
• @dasl/tile-writer — write tiles into .tile files
• @dasl/tile-lexicon — MASL schema and shared types
• @dasl/atile — the tile-publishing CLI

License

Apache-2.0