libp2p

libp2p is the networking stack of IPFS, a modular networking library to solve P2P application needs.

Table of Contents

• Background
• Bundles
• Usage
  • Install
  • API
• Development
  • Tests
  • Packages
• Contribute
• License

Background

libp2p is the product of a long and arduous quest to understand the evolution of the Internet networking stack. In order to build P2P applications, dev have long had to made custom ad-hoc solutions to fit their needs, sometimes making some hard assumptions about their runtimes and the state of the network at the time of their development. Today, looking back more than 20 years, we see a clear pattern in the types of mechanisms built around the Internet Protocol, IP, which can be found throughout many layers of the OSI layer system, libp2p distils these mechanisms into flat categories and defines clear interfaces that once exposed, enable other protocols and applications to use and swap them, enabling upgradability and adaptability for the runtime, without breaking the API.

We are in the process of writting better documentation, blog posts, tutorials and a formal specification. Today you can find:

• libp2p.io - The libp2p Website (WIP)
• Specification (WIP)
• Talks
  • libp2p <3 ethereum at DEVCON2 video slides demo-1 demo-2
• Articles
  • The overview of libp2p

To sum up, libp2p is a "network stack" -- a protocol suite -- that cleanly separates concerns, and enables sophisticated applications to only use the protocols they absolutely need, without giving up interoperability and upgradeability. libp2p grew out of IPFS, but it is built so that lots of people can use it, for lots of different projects.

Bundles

With its modular nature, libp2p can be found being used in different projects with different sets of features, while preserving the same top level API. js-libp2p is only a skeleton and should not be installed directly, if you are looking for a prebundled libp2p stack, please check:

• libp2p-ipfs-nodejs - The libp2p build used by js-ipfs when run in Node.js
• libp2p-ipfs-browser - The libp2p build used by js-ipfs when run in a Browser (that supports WebRTC)

If you have developed a libp2p bundle, please consider submitting it to this list so that it can be found easily by the users of libp2p.

Install

Again, as noted above, this module is only a skeleton and should not be used directly other than libp2p bundle implementors that want to extend its code.

npm install --save libp2p

Usage

Extending libp2p skeleton

libp2p becomes very simple and basically acts as a glue for every module that compose this library. Since it can be highly customized, it requires some setup. What we recommend is to have a libp2p build for the system you are developing taking into account in your needs (e.g. for a browser working version of libp2p that acts as the network layer of IPFS, we have a built and minified version that browsers can require).

Example:

// Creating a bundle that adds:
//   transport: websockets + tcp
//   stream-muxing: SPDY
//   crypto-channel: secio
//   discovery: multicast-dns

const libp2p = require('libp2p')
const TCP = require('libp2p-tcp')
const WS = require('libp2p-websockets')
const spdy = require('libp2p-spdy')
const secio = require('libp2p-secio')
const MulticastDNS = require('libp2p-mdns')

class Node extends libp2p {
  constructor (peerInfo, peerBook, options) {
    options = options || {}

    const modules = {
      transport: [
        new TCP(),
        new WS()
      ],
      connection: {
        muxer: [
          spdy
        ],
        crypto: [
          secio
        ]
      },
      discovery: [
        new MulticastDNS(peerInfo, 'your-identifier')
      ]
    }

    super(modules, peerInfo, peerBook, options)
  }
}

// Now all the nodes you create, will have TCP, WebSockets, SPDY, SECIO and MulticastDNS support.

API

Create a Node - new libp2p.Node([peerInfo, peerBook, options])

Creates an instance of the libp2p.Node.

• peerInfo: instance of PeerInfo that contains the PeerId, Keys and multiaddrs of the libp2p Node. Optional.
• peerBook: instance of PeerBook that contains the PeerInfo of known peers. Optional.
• options: Object containing custom options for the bundle.

libp2p.start(callback)

Start the libp2p Node.

callback is a function with the following function (err) {} signature, where err is an Error in case starting the node fails.

libp2p.stop(callback)

Stop the libp2p Node.

callback is a function with the following function (err) {} signature, where err is an Error in case stopping the node fails.

libp2p.dial(peer [, protocol, callback])

Dials to another peer in the network.

• peer: can be an instance of PeerInfo, PeerId or multiaddr
• protocol: String that defines the protocol (e.g '/ipfs/bitswap/1.1.0')

callback is a function with the following function (err, conn) {} signature, where err is an Error in of failure to dial the connection and conn is a Connection instance in case of a protocol selected, if not it is undefined.

`libp2p.hangUp(peer, callback)

Closes an open connection with a peer, graciously.

• peer: can be an instance of PeerInfo, PeerId or multiaddr

callback is a function with the following function (err) {} signature, where err is an Error in case stopping the node fails.

libp2p.handle(protocol, handlerFunc [, matchFunc])

Handle new protocol

• protocol: String that defines the protocol (e.g '/ipfs/bitswap/1.1.0')
• handlerFunc: Function with signature function (protocol, conn) {}
• matchFunc: Function for matching on protocol (exact matching, semver, etc). Default to exact match.

`libp2p.unhandle(protocol)

Stop handling protocol

• protocol: String that defines the protocol (e.g '/ipfs/bitswap/1.1.0')

libp2p.on('peer', (peer) => {})

Peer has been discovered.

• peer: instance of PeerInfo

libp2p.isOn()

Check if libp2p is started

libp2p.ping(peer [, options], callback)

Ping a node in the network

libp2p.peerBook

PeerBook instance of the node

libp2p.peerInfo

PeerInfo instance of the node

---

SOON™

libp2p.findPeers

libp2p.findProviders

libp2p.record.put

libp2p.record.get

Packages

List of packages currently in existence for libp2p

Package	Version	Dependencies	DevDependencies
Bundles
libp2p-ipfs-nodejs
libp2p-ipfs-browser
Transports
libp2p-utp
libp2p-websockets
libp2p-webrtc-star
Connection Upgrades
interface-connection
Stream Muxers
interface-stream-muxer
libp2p-spdy
libp2p-multiplex
Discovery
libp2p-mdns-discovery
libp2p-railing
Crypto Channels
libp2p-secio
Peer Routing
libp2p-kad-routing
Content Routing
interface-record-store
libp2p-record
libp2p-distributed-record-store
libp2p-kad-record-store
Generics
libp2p-swarm
libp2p-ping
multistream-select
Data Types
peer-book
peer-id

Contribute

The libp2p implementation in JavaScript is a work in progress. As such, there are a few things you can do right now to help out:

• Go through the modules and check out existing issues. This would be especially useful for modules in active development. Some knowledge of IPFS/libp2p may be required, as well as the infrasture behind it - for instance, you may need to read up on p2p and more complex operations like muxing to be able to help technically.
• Perform code reviews. Most of this has been developed by @diasdavid, which means that more eyes will help a) speed the project along b) ensure quality and c) reduce possible future bugs.
• Add tests. There can never be enough tests.

License

MIT © David Dias