Module @helia/car

@helia/car provides import and export methods to read/write Car files to Helia's blockstore.

See the Car interface for all available operations.

By default it supports dag-pb, dag-cbor, dag-json and raw CIDs, more esoteric DAG walkers can be passed as an init option.

Example: Exporting a DAG as a CAR file

import { createHelia } from 'helia'
import { car } from '@helia/car'
import { CID } from 'multiformats/cid'
import nodeFs from 'node:fs'

const helia = await createHelia()
const cid = CID.parse('QmFoo...')

const c = car(helia)
const out = nodeFs.createWriteStream('example.car')

for await (const buf of c.export(cid)) {
  out.write(buf)
}

out.end()

Example: Exporting a part of a UnixFS DAG as a CAR file

import { createHelia } from 'helia'
import { car, UnixFSPath } from '@helia/car'
import { CID } from 'multiformats/cid'
import nodeFs from 'node:fs'

const helia = await createHelia()
const cid = CID.parse('QmFoo...')

const c = car(helia)
const out = nodeFs.createWriteStream('example.car')

for await (const buf of c.export(cid, {
  traversal: new UnixFSPath('/foo/bar/baz.txt')
})) {
  out.write(buf)
}

out.end()

Example: Importing all blocks from a CAR file

import { createHelia } from 'helia'
import { unixfs } from '@helia/unixfs'
import { car } from '@helia/car'
import { CarReader } from '@ipld/car'
import { Readable } from 'node:stream'
import nodeFs from 'node:fs'

const helia = await createHelia({
  // ... helia config
})

// import the car
const inStream = nodeFs.createReadStream('example.car')
const reader = await CarReader.fromIterable(inStream)

const c = car(helia)
await c.import(reader)

Classes

BlockExporter
CIDPath
GraphSearch
SubgraphExporter
UnixFSExporter
UnixFSPath

Interfaces

Car
CarComponents
ExportCarOptions
ExportStrategy
TraversalStrategy

Functions

car