ipfs-unixfs

ipfs-unixfs

JavaScript implementation of IPFS' unixfs (a Unix FileSystem representation on top of a MerkleDAG)

Table of contents

• Install
  • Browser <script> tag
• Spec
  • Use in Node.js
  • Use in a browser with browserify, webpack or any other bundler
• Examples
  • Create a file composed by several blocks
  • Create a directory that contains several files
  • UnixFS Data Structure
  • create an unixfs Data element
  • add and remove a block size to the block size list
  • get total fileSize
  • marshal and unmarshal
  • is this UnixFS entry a directory?
  • has an mtime been set?
• API Docs
• License
• Contribute

Install

$ npm i ipfs-unixfs

Browser <script> tag

Loading this module through a script tag will make it's exports available as IpfsUnixfs in the global namespace.

<script src="https://unpkg.com/ipfs-unixfs/dist/index.min.js"></script>

Spec

The UnixFS spec can be found inside the ipfs/specs repository

Use in Node.js

import { UnixFS } from 'ipfs-unixfs'

Use in a browser with browserify, webpack or any other bundler

The code published to npm that gets loaded on require is in fact a ES5 transpiled version with the right shims added. This means that you can require it and use with your favourite bundler without having to adjust asset management process.

import { UnixFS } from 'ipfs-unixfs'

Examples

Create a file composed by several blocks

const data = new UnixFS({ type: 'file' })
data.addBlockSize(256) // add the size of each block
data.addBlockSize(256)
// ...

Create a directory that contains several files

Creating a directory that contains several files is achieve by creating a unixfs element that identifies a MerkleDAG node as a directory. The links of that MerkleDAG node are the files that are contained in this directory.

const data = new UnixFS({ type: 'directory' })

UnixFS Data Structure

syntax = "proto2";

message Data {
  enum DataType {
    Raw = 0;
    Directory = 1;
    File = 2;
    Metadata = 3;
    Symlink = 4;
    HAMTShard = 5;
  }

  required DataType Type = 1;
  optional bytes Data = 2;
  optional uint64 filesize = 3;
  repeated uint64 blocksizes = 4;
  optional uint64 hashType = 5;
  optional uint64 fanout = 6;
  optional uint32 mode = 7;
  optional UnixTime mtime = 8;
}

message UnixTime {
  required int64 Seconds = 1;
  optional fixed32 FractionalNanoseconds = 2;
}

message Metadata {
  optional string MimeType = 1;
}

create an unixfs Data element

const data = new UnixFS([options])

options is an optional object argument that might include the following keys:

• type (string, default file): The type of UnixFS entry. Can be:
  • raw
  • directory
  • file
  • metadata
  • symlink
  • hamt-sharded-directory
• data (Uint8Array): The optional data field for this node
• blockSizes (Array, default: []): If this is a file node that is made up of multiple blocks, blockSizes is a list numbers that represent the size of the file chunks stored in each child node. It is used to calculate the total file size.
• mode (Number, default 0644 for files, 0755 for directories/hamt-sharded-directories) file mode
• mtime (Date, { secs, nsecs }, { Seconds, FractionalNanoseconds }, [ secs, nsecs ]): The modification time of this node

add and remove a block size to the block size list

data.addBlockSize(<size in bytes>)

data.removeBlockSize(<index>)

get total fileSize

data.fileSize() // => size in bytes

marshal and unmarshal

const marshaled = data.marshal()
const unmarshaled = Unixfs.unmarshal(marshaled)

is this UnixFS entry a directory?

const dir = new Data({ type: 'directory' })
dir.isDirectory() // true

const file = new Data({ type: 'file' })
file.isDirectory() // false

has an mtime been set?

If no modification time has been set, no mtime property will be present on the Data instance:

const file = new Data({ type: 'file' })
file.mtime // undefined

Object.prototype.hasOwnProperty.call(file, 'mtime') // false

const dir = new Data({ type: 'dir', mtime: new Date() })
dir.mtime // { secs: Number, nsecs: Number }

API Docs

• https://ipfs.github.io/js-ipfs-unixfs/modules/ipfs_unixfs.html

License

Licensed under either of

• Apache 2.0, (LICENSE-APACHE / http://www.apache.org/licenses/LICENSE-2.0)
• MIT (LICENSE-MIT / http://opensource.org/licenses/MIT)

Contribute

Contributions welcome! Please check out the issues.

Also see our contributing document for more information on how we work, and about contributing in general.

Please be aware that all interactions related to this repo are subject to the IPFS Code of Conduct.

Unless you explicitly state otherwise, any contribution intentionally submitted for inclusion in the work by you, as defined in the Apache-2.0 license, shall be dual licensed as above, without any additional terms or conditions.