libp2p-pubsub

js-libp2p-pubsub

libp2p-pubsub is the base protocol for libp2p pubsub implementations. This module is responsible for registering the protocol with libp2p, as well as managing the logic regarding pubsub connections with other peers.

Lead Maintainer

Vasco Santos.

Table of Contents

• Install
• Usage
• API
• Contribute
• License

Install

> npm install libp2p-pubsub

Usage

libp2p-pubsub abstracts the implementation protocol registration within libp2p and takes care of all the protocol connections. This way, a pubsub implementation can focus on its routing algorithm, instead of also needing to create the setup for it.

A pubsub implementation MUST override the _processMessages, publish, subscribe, unsubscribe and getTopics functions.

Other functions, such as _onPeerConnected, _onPeerDisconnected, _addPeer, _removePeer, start and stop may be overwritten if the pubsub implementation needs to customize their logic. Implementations overriding start and stop MUST call super. The start function is responsible for registering the pubsub protocol with libp2p, while the stop function is responsible for unregistering the pubsub protocol and closing pubsub connections.

All the remaining functions MUST NOT be overwritten.

The following example aims to show how to create your pubsub implementation extending this base protocol. The pubsub implementation will handle the subscriptions logic.

TODO: add explanation for registrar!

const Pubsub = require('libp2p-pubsub')

class PubsubImplementation extends Pubsub {
  constructor({ peerInfo, registrar, ...options })
    super({
      debugName: 'libp2p:pubsub',
      multicodecs: '/pubsub-implementation/1.0.0',
      peerInfo: peerInfo,
      registrar: registrar,
      signMessages: options.signMessages,
      strictSigning: options.strictSigning
    })
  }

  _processMessages(idB58Str, conn, peer) {
    // Required to be implemented by the subclass
    // Process each message accordingly
  }

  publish() {
    // Required to be implemented by the subclass
  }

  subscribe() {
    // Required to be implemented by the subclass
  }

  unsubscribe() {
    // Required to be implemented by the subclass
  }

  getTopics() {
    // Required to be implemented by the subclass
  }
}

API

The following specified API should be the base API for a pubsub implementation on top of libp2p.

Start

Starts the pubsub subsystem. The protocol will be registered to libp2p, which will result in pubsub being notified when peers who support the protocol connect/disconnect to libp2p.

pubsub.start()

Returns

Type	Description
Promise<void>	resolves once pubsub starts

Stop

Stops the pubsub subsystem. The protocol will be unregistered from libp2p, which will remove all listeners for the protocol and the established connections will be closed.

pubsub.stop()

Returns

Type	Description
Promise<void>	resolves once pubsub stops

Publish

Publish data messages to pubsub topics.

pubsub.publish(topics, messages)

Parameters

Name	Type	Description
topics	`Array	string`
messages	`Array	any`

Returns

Type	Description
Promise<void>	resolves once messages are published to the network

Subscribe

Subscribe to the given topic(s).

pubsub.subscribe(topics)

Parameters

Name	Type	Description
topics	`Array	string`

Unsubscribe

Unsubscribe from the given topic(s).

pubsub.unsubscribe(topics)

Parameters

Name	Type	Description
topics	`Array	string`

Get Topics

Get the list of topics which the peer is subscribed to.

pubsub.getTopics()

Returns

Type	Description
Array<String>	Array of subscribed topics

Get Peers Subscribed to a topic

Get a list of the PeerId strings that are subscribed to one topic.

pubsub.getSubscribers(topic)

Parameters

Name	Type	Description
topic	string	pubsub topic

Returns

Type	Description
Array<string>	Array of base-58 PeerId's

Validate

Validates the signature of a message.

pubsub.validate(message)

Parameters

Name	Type	Description
message	Message	a pubsub message

Returns

Type	Description
Promise<Boolean>	resolves to true if the message is valid

Implementations using this base protocol

You can use the following implementations as examples for building your own pubsub implementation.

• libp2p/js-libp2p-floodsub
• ChainSafe/gossipsub-js

Contribute

Feel free to join in. All welcome. Open an issue!

This repository falls under the IPFS Code of Conduct.

License

Copyright (c) Protocol Labs, Inc. under the MIT License. See LICENSE file for details.