Need help using @chainsafe/libp2p-gossipsub

Users and Developers
1

Hi, I’m trying to use gossipsub to build a decentralized mobile chat app @ ETHIndia.

I’m using GitHub - ChainSafe/js-libp2p-gossipsub: TypeScript implementation of Gossipsub but need some help

Here is the code to setup libp2p node:

import { GossipSub } from '@chainsafe/libp2p-gossipsub'

const createNode = async () => {
    const node = await createLibp2p({
        addresses: {
            // add a listen address (localhost) to accept TCP connections on a random port
            listen: ['/ip4/0.0.0.0/tcp/0/ws']
        },
        // transports: [tcp()],
        transports: [webSockets({
            filters: all
        })],
        connectionEncryption: [noise()],
        streamMuxers: [mplex()],
        peerDiscovery: [
            bootstrap({
                list: bootstrapMultiaddrs,
            })
        ],
        connectionManager: {
            autoDial: true,
        },
        dht: kadDHT(),
        // pubsub: floodsub()
        pubsub: new GossipSub({
            emitSelf: true
        })
    })
    return node
}

const options = {}
const gsub = new GossipSub(node, options)
await gsub.start()

gsub.on('fruit', (data) => {
    console.log(data)
})

gsub.subscribe('fruit')

gsub.publish('fruit', new TextEncoder().encode('banana'))

And here is the error I’m facing right now:

gsub.on('fruit', (data) => {
     ^

TypeError: gsub.on is not a function
    at file:///home/boogeyman/GIT/Hub/ohjihq/js-libp2p-playground/src/index.js:62:6
    at process.processTicksAndRejections (node:internal/process/task_queues:95:5)

Node.js v18.10.0
2

You should take a look at the libp2p pubsub example if you haven’t already:

I think the reademe examples in ChainSafe’s Gossipsub is outdated, the GossipSub class extends libp2p’s EventEmitter which extends EventTarget so instead of using on you probably want to use addEventListener:

import { gossipsub } from '@chainsafe/libp2p-gossipsub'

const gsub = gossipsub(options)(node)

await gsub.start()

gsub.addEventListener('message', (message) => {
  console.log(`${message.detail.topic}:`, new TextDecoder().decode(message.detail.data))
})

gsub.subscribe('fruit')

gsub.publish('fruit', new TextEncoder().encode('banana'))

// ...
1 Like
3

Hi @saul ,

Thank you!

I am now able to use the gossipsub function with my libp2p node and options.

With selfEmit: true in the config, I am able to see my own messages.

However I am unable to see the messages sent by other peers.

4

The nodes need to be connected and subscribed to the same topic to gossip about messages.

Also your original code has two instances of gossipsub, this may lead to bugs/confusion you should probably be doing the following (as opposed to my last code example):

const node = await createLibp2p({
  // ...
  pubsub: gossipsub({
    emitSelf: true
   })
  // ...
});

// ...

node.pubsub.subscribe("fruit");

node.pubsub.addEventListener("message", (evt) => {
  // ...
});