@jimpick/hyperdrive-hyperdb-backend

    9.12.3-10 • Public • Published

    Hyperdrive

    Hyperdrive is a secure, real time distributed file system

    npm install hyperdrive

    Build Status

    Usage

    Hyperdrive aims to implement the same API as Node.js' core fs module.

    var hyperdrive = require('hyperdrive')
    var archive = hyperdrive('./my-first-hyperdrive') // content will be stored in this folder
     
    archive.writeFile('/hello.txt', 'world', function (err) {
      if (err) throw err
      archive.readdir('/', function (err, list) {
        if (err) throw err
        console.log(list) // prints ['hello.txt']
        archive.readFile('/hello.txt', 'utf-8', function (err, data) {
          if (err) throw err
          console.log(data) // prints 'world'
        })
      })
    })

    A big difference is that you can replicate the file system to other computers! All you need is a stream.

    var net = require('net')
     
    // ... on one machine
     
    var server = net.createServer(function (socket) {
      socket.pipe(archive.replicate()).pipe(socket)
    })
     
    server.listen(10000)
     
    // ... on another
     
    var clonedArchive = hyperdrive('./my-cloned-hyperdrive', origKey)
    var socket = net.connect(10000)
     
    socket.pipe(clonedArchive.replicate()).pipe(socket)

    It also comes with build in versioning and real time replication. See more below.

    API

    var archive = hyperdrive(storage, [key], [options])

    Create a new hyperdrive. Storage should be a function or a string.

    If storage is a string content will be stored inside that folder.

    If storage is a function it is called with a string name for each abstract-random-access instance that is needed to store the archive.

    Options include:

    {
      sparse: true, // only download data on content feed when it is specifically requested
      sparseMetadata: true // only download data on metadata feed when requested
      metadataStorageCacheSize: 65536 // how many entries to use in the metadata hypercore's LRU cache
      contentStorageCacheSize: 65536 // how many entries to use in the content hypercore's LRU cache
      treeCacheSize: 65536 // how many entries to use in the append-tree's LRU cache
    }

    Note that a cloned hyperdrive archive can be "sparse". Usually (by setting sparse: true) this means that the content is not downloaded until you ask for it, but the entire metadata feed is still downloaded. If you want a very sparse archive, where even the metadata feed is not downloaded until you request it, then you should also set sparseMetadata: true.

    var stream = archive.replicate([options])

    Replicate this archive. Options include

    {
      live: false, // keep replicating
      download: true, // download data from peers?
      upload: true // upload data to peers?
    }

    archive.version

    Get the current version of the archive (incrementing number).

    archive.key

    The public key identifying the archive.

    archive.discoveryKey

    A key derived from the public key that can be used to discovery other peers sharing this archive.

    archive.writable

    A boolean indicating whether the archive is writable.

    archive.on('ready')

    Emitted when the archive is fully ready and all properties has been populated.

    archive.on('error', err)

    Emitted when a critical error during load happened.

    var oldDrive = archive.checkout(version)

    Checkout a readonly copy of the archive at an old version.

    archive.download([path], [callback])

    Download all files in path of current version. If no path is specified this will download all files.

    You can use this with .checkout(version) to download a specific version of the archive.

    archive.checkout(version).download()

    var stream = archive.history([options])

    Get a stream of all changes and their versions from this archive.

    var stream = archive.createReadStream(name, [options])

    Read a file out as a stream. Similar to fs.createReadStream.

    Options include:

    {
      start: optionalByteOffset, // similar to fs
      end: optionalInclusiveByteEndOffset, // similar to fs
      length: optionalByteLength
    }

    archive.readFile(name, [options], callback)

    Read an entire file into memory. Similar to fs.readFile.

    Options can either be an object or a string

    Options include:

    {
      encoding: string
      cached: true|false // default: false,
    }

    or a string can be passed as options to simply set the encoding - similar to fs.

    If cached is set to true, this function returns results only if they have already been downloaded.

    var stream = archive.createDiffStream(version, [options])

    Diff this archive this another version. version can both be a version number of a checkout instance of the archive. The data objects looks like this

    {
      type: 'put' | 'del',
      name: '/some/path/name.txt',
      value: {
        // the stat object
      }
    }

    var stream = archive.createWriteStream(name, [options])

    Write a file as a stream. Similar to fs.createWriteStream. If options.cached is set to true, this function returns results only if they have already been downloaded.

    archive.writeFile(name, buffer, [options], [callback])

    Write a file from a single buffer. Similar to fs.writeFile.

    archive.unlink(name, [callback])

    Unlinks (deletes) a file. Similar to fs.unlink.

    archive.mkdir(name, [options], [callback])

    Explictly create an directory. Similar to fs.mkdir

    archive.rmdir(name, [callback])

    Delete an empty directory. Similar to fs.rmdir.

    archive.readdir(name, [options], [callback])

    Lists a directory. Similar to fs.readdir.

    Options include:

    {
        cached: true|false, // default: false
    }

    If cached is set to true, this function returns results from the local version of the archive’s append-tree. Default behavior is to fetch the latest remote version of the archive before returning list of directories.

    archive.stat(name, callback)

    Stat an entry. Similar to fs.stat. Sample output:

    Stat {
      dev: 0,
      nlink: 1,
      rdev: 0,
      blksize: 0,
      ino: 0,
      mode: 16877,
      uid: 0,
      gid: 0,
      size: 0,
      offset: 0,
      blocks: 0,
      atime: 2017-04-10T18:59:00.147Z,
      mtime: 2017-04-10T18:59:00.147Z,
      ctime: 2017-04-10T18:59:00.147Z,
      linkname: undefined }
    

    The output object includes methods similar to fs.stat:

    var stat = archive.stat('/hello.txt')
    stat.isDirectory()
    stat.isFile()

    archive.lstat(name, callback)

    Stat an entry but do not follow symlinks. Similar to fs.lstat.

    archive.access(name, callback)

    Similar to fs.access.

    archive.open(name, flags, [mode], callback)

    Open a file and get a file descriptor back. Similar to fs.open.

    Note that currently only read mode is supported in this API.

    archive.read(fd, buf, offset, len, position, callback)

    Read from a file descriptor into a buffer. Similar to fs.read.

    archive.close(fd, [callback])

    Close a file. Similar to fs.close.

    archive.close([callback])

    Closes all open resources used by the archive. The archive should no longer be used after calling this.

    Keywords

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    Install

    npm i @jimpick/hyperdrive-hyperdb-backend

    DownloadsWeekly Downloads

    21

    Version

    9.12.3-10

    License

    MIT

    Unpacked Size

    111 kB

    Total Files

    19

    Last publish

    Collaborators

    • jimpick