joehand/dat-backup

Create and share static backups of a Dat archive.

dat-backup

Backup a dat to local storage. Useful for:

• Storing full history
• Creating local backups of data (good for offline backups!)
• More efficient storage (all content, latest and historic, is stored as a single content.data file)

Usage

A dat backup is good for situations where an archive is only storing the latest content but you want to keep historic version of content around locally, either temporarily or permanently.

var createBackup = require('dat-backup')

var archive = hyperdrive('/dir', {latest: true}) // some existing archive or dat-node instance

// default dir is ~/.dat/backups/<discovery-key>
var backup = createBackup(archive, {dir: '/big-hd/' + archive.discoveryKey.toString('hex')})

backup.ready(function (err) {
  if (err) throw err

  // backup archive at current version
  backup.add(function () {
  	console.log('archive backed up at version: ', archive.version)
  })

  // List all file versions available in archive backup
  backup.list(function (err, files) {
    if (err) throw err
    console.log(files)
  })
})

API

var backup = createBackup(source, [opts])

source is either a hyperdrive archive or dat-node instanace, dat.

Options are:

• opts.dir: where to store backups, defaults to ~/.dat/backup/discKey.slice(0, 2), discKey.slice(2)

backup.ready()

Initalize the backup and make sure it is ready for adding, etc. This is often called automatically but for sync commands you may need to call it first, e.g. backup.list().

backup.add([opts], cb)

Create a new backup of the archive at current version. Will backup all content available in the current archive, but not any remote archives. callback will be called when finished, unless live.

Options are:

• opts.live: Do a live backup, backing up content as it is updated. Will not callback.

backup.remove(start, [end], cb)

Remove archive version(s) from local backup.

Start and end have the following properties: {version: 0}. end.version defaults to start.version + 1.

You can also pass content block numbers directly (equivilant to archive.content.clear(start, end, cb)).

var stream = backup.list([opts], [cb])

List all data available in backup. Streams a list of files from archive.history() if they are backed up. opts are passed to archive.history.

If cb is provided, stream will collect the list and callback with (err, list).

backup.serve()

Serve data from a backup. This will allow users to download any data that is backed up.

License

MIT