@multiformats/multiaddr

What is @multiformats/multiaddr?

@multiformats/multiaddr is a JavaScript implementation of the multiaddr format, which is a self-describing network address format. It is used to represent addresses in a way that is protocol-agnostic and can be easily extended to support new protocols.

What are @multiformats/multiaddr's main functionalities?

Create a Multiaddr

This feature allows you to create a new multiaddr instance from a string. The example demonstrates creating a multiaddr for an IPv4 address with a TCP port.

const multiaddr = require('@multiformats/multiaddr');
const addr = multiaddr('/ip4/127.0.0.1/tcp/4001');
console.log(addr.toString());

Parse a Multiaddr

This feature allows you to parse a multiaddr and extract protocol names. The example shows how to get the protocol names from a multiaddr.

const multiaddr = require('@multiformats/multiaddr');
const addr = multiaddr('/ip4/127.0.0.1/tcp/4001');
console.log(addr.protoNames());

Encapsulate and Decapsulate

This feature allows you to encapsulate and decapsulate addresses. The example demonstrates adding a UDP layer to an existing address and then removing it.

const multiaddr = require('@multiformats/multiaddr');
const addr = multiaddr('/ip4/127.0.0.1/tcp/4001');
const encapsulated = addr.encapsulate('/udp/1234');
console.log(encapsulated.toString());
const decapsulated = encapsulated.decapsulate('/udp');
console.log(decapsulated.toString());

Other packages similar to @multiformats/multiaddr

ip

The 'ip' package provides utilities for IP address manipulation, including parsing and formatting. While it focuses on IP addresses specifically, @multiformats/multiaddr is more versatile, supporting a wider range of protocols and encapsulation.

netaddr

The 'netaddr' package is used for network address manipulation, including IP and CIDR operations. It is similar in functionality to 'ip', but @multiformats/multiaddr offers a more comprehensive approach to handling multi-protocol addresses.

README

@multiformats/multiaddr

multiaddr implementation (binary + string representation of network addresses)

Table of contents

• Install
• Lead Maintainer
• Background
  • What is multiaddr?
  • Browser: <script> Tag
• Usage
• API
• Resolvers
• License
• Contribute

Install

$ npm i @multiformats/multiaddr

Lead Maintainer

Jacob Heun

Background

What is multiaddr?

A standard way to represent addresses that

• support any standard network protocol
• are self-describing
• have a binary packed format
• have a nice string representation
• encapsulate well

npm i multiaddr

Browser: <script> Tag

Loading this module through a script tag will make the Multiaddr obj available in the global namespace.

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

Usage

// if we are coming from <= 8.x you can use the factory function
const { multiaddr } = require('multiaddr')
const addr =  multiaddr("/ip4/127.0.0.1/udp/1234")
// <Multiaddr /ip4/127.0.0.1/udp/1234>

// or just the class directly
const { Multiaddr } = require('multiaddr')

const addr = new Multiaddr("/ip4/127.0.0.1/udp/1234")
// <Multiaddr /ip4/127.0.0.1/udp/1234>

addr.bytes
// <Uint8Array 04 7f 00 00 01 11 04 d2>

addr.toString()
// '/ip4/127.0.0.1/udp/1234'

addr.protos()
/*
[
  {code: 4, name: 'ip4', size: 32},
  {code: 273, name: 'udp', size: 16}
]
*/

// gives you an object that is friendly with what Node.js core modules expect for addresses
addr.nodeAddress()
/*
{
  family: 4,
  port: 1234,
  address: "127.0.0.1"
}
*/

addr.encapsulate('/sctp/5678')
// <Multiaddr /ip4/127.0.0.1/udp/1234/sctp/5678>

API

https://multiformats.github.io/js-multiaddr/

Resolvers

multiaddr allows multiaddrs to be resolved when appropriate resolvers are provided. This module already has resolvers available, but you can also create your own. Resolvers should always be set in the same module that is calling multiaddr.resolve() to avoid conflicts if multiple versions of multiaddr are in your dependency tree. To provide multiaddr resolvers you can do:

const { Multiaddr } = require('multiaddr')
const resolvers = require('multiaddr/src/resolvers')

Multiaddr.resolvers.set('dnsaddr', resolvers.dnsaddrResolver)

The available resolvers are:

Name	type	Description
dnsaddrResolver	dnsaddr	dnsaddr resolution with TXT Records

A resolver receives a Multiaddr as a parameter and returns a Promise<Array<string>>.

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

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.