@synonymdev/hyperdrive

Hyperdrive

Hyperdrive is a secure, real-time distributed file system

Install

npm install hyperdrive@next

Note this is the Hyperdrive 11 preview based on Hypercore 10

Usage

const Hyperdrive = require('hyperdrive')
const Corestore = require('corestore')

const corestore = new Corestore('storage')

const drive = new Hyperdrive(corestore, /* optionalKey */)

const ws = drive.createWriteStream('/blob.txt')

ws.write('Hello, ')
ws.write('world!')
ws.end()

ws.on('close', function () {
  const rs = drive.createReadStream('/blob.txt')
  rs.pipe(process.stdout) // prints Hello, world!
})

API

const drive = new Hyperdrive(corestore, [key])

Creates a new Hyperdrive instance.

corestore must be an instance of Corestore.

key should be a Hypercore public key. If you do not set this, Hyperdrive will use the core at { name: 'db' } in the passed Corestore instance.

await drive.ready()

Wait for the drive to fully open. In general, you do NOT need to wait for ready unless checking a synchronous property on drive since internals await this themselves.

const buffer = await drive.get(path)

Returns the blob at path in the drive. Internally, Hyperdrive contains a metadata index of entries that "point" to offsets in a Hyperblobs instance. Blobs themselves are accessible via drive.get(path), whereas entries are accessible via drive.entry(path). If no blob exists at path, returns null.

const stream = drive.createReadStream(path, options)

Returns a stream that can be used to read out the blob stored in the drive at path.

options are the same as the options to Hyperblobs().createReadStream(path, options).

const entry = await drive.entry(path)

Returns the entry at path in the drive. An entry holds metadata about a path, currently:

{
  seq: Number,
  key: String,
  value: {
    executable: Boolean, // whether the blob at path is an executable
    linkname: null // if entry not symlink, otherwise a string to the entry this links to
    blob: { // a Hyperblob id that can be used to fetch the blob associated with this entry
      blockOffset: Number,
      blockLength: Number,
      byteOffset: Number,
      byteLength: Number
    },
    metadata: null
  }
}

await drive.symlink(path, linkname)

Creates an entry in drive at path that points to the entry at linkname. Note, if a blob entry currently exists at path then drive.symlink(path, linkname) will overwrite the entry and drive.get(path) will return null, while drive.entry(path) will return the entry with symlink information.

const hyperblobs = await drive.getBlobs()

Returns the hyperblobs instance storing the blobs indexed by drive entries.

const fs = require('fs')
const Corestore = require('corestore')
const Hyperdrive = require('hyperdrive')

const drive = new Hyperdrive(new Corestore('storage'))

await drive.put(__filename, fs.readFileSync(__filename))
const bufFromGet = await drive.get(__filename)

const { value: entry } = await drive.entry(__filename)
const blobs = await drive.getBlobs()
const bufFromEntry = blobs.get(entry.blob)

console.log(Buffer.compare(bufFromGet, bufFromEntry)) // prints 0

const stream = await drive.entries([options])

Returns a read stream of entries in the drive.

options are the same as the options to Hyperbee().createReadStream(options).

await drive.put(path, blob, [options])

Sets the blob in the drive at path.

path should be a utf8 string. blob should be a Buffer.

options includes:

{
  executable: true | false // whether the blob is executable or not
}

ws = drive.createWriteStream(path, [options])

Stream a blob into the drive at path. Options include

{
  executable: true | false // whether the blob is executable or not
}

await drive.del(path)

Removes the entry at path from the drive. If a blob corresponding to the entry at path exists, it is not currently deleted.

const hypercore = drive.core

The underlying Hypercore backing the drive.

const buffer = drive.key

The public key of the Hypercore backing the drive.

const buffer = drive.discoveryKey

The hash of the public key of the Hypercore backing the drive, can be used to seed the drive using Hyperswarm.

const buffer = drive.contentKey

The public key of the Hyperblobs instance holding blobs associated with entries in the drive.

const integer = drive.version

The version (offset in the underlying Hypercore) of the drive.

const Hyperdrive = drive.checkout(version)

Checks out a read-only snapshot of a Hyperdrive at a particular version.

const fs = require('fs')
const Corestore = require('corestore')
const Hyperdrive = require('hyperdrive')

const drive = new Hyperdrive(new Corestore('storage'))

await drive.put('/fst-file.txt', fs.readFileSync('fst-file.txt'))

const version = drive.version

await drive.put('/snd-file.txt', fs.readFileSync('snd-file.txt'))

const snapshot = drive.checkout(version)

console.log(await drive.get('/snd-file.txt')) // prints Buffer
console.log(await snapshot.get('/snd-file.txt')) // prints null
console.log(Buffer.compare(await drive.get('/fst-file.txt'), await snapshot.get('/fst-file.txt'))) // prints 0

const stream = drive.diff(version, folder, [options])

Efficiently create a stream of the shallow changes to folder between version and drive.version. Each entry is sorted by key and looks like this:

{
  left: <the entry in folder at drive.version for some path>,
  right: <the entry in folder at drive.checkout(version) for some path>
}

If an entry exists in drive.version of the folder but not in version, then left is set and right will be null, and vice versa.

await drive.downloadDiff(version, folder, [options])

Downloads all the blobs in folder corresponding to entries in drive.checkout(version) that are not in drive.version. In other words, downloads all the blobs added to folder up to version of the drive.

const stream = drive.list(folder, [options])

Returns a stream of all entries in the drive at paths prefixed with folder. Options include:

{
  recursive: true | false // whether to descend into all subfolders or not
}

await drive.download(folder, [options])

Downloads the blobs corresponding to all entries in the drive at paths prefixed with folder. Options are the same as those for drive.list(folder, [options]).

const stream = drive.readdir(folder)

Returns a stream of all subpaths of entries in drive stored at paths prefixed by folder.

await drive.put('/parent/child', Buffer.from('child'))
await drive.put('/parent/sibling', Buffer.from('sibling'))
for await (const path of drive.readdir('/parent')) console.log(path) // prints "child", then prints "sibling"

await downloadRange(dbRanges, blobRanges)

Downloads the entries and blobs stored in the ranges dbRanges and blobRanges.

const batch = drive.batch()

Atomically mutate the drive, has the same interface as Hyperdrive.

await batch.flush()

Atomically commit a batch of mutations to the underlying drive.

await drive.close()

Close the drive and its underlying Hypercore backed datastructures.