js-libp2p-gossipsub
==================

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## Lead Maintainer

[Cayman Nava](https://github.com/wemeetagain)

## Table of Contents

* [Specs](#specs)
* [Install](#Install)
* [Usage](#Usage)
* [API](#API)
* [Contribute](#Contribute)
* [License](#License)

## Specs
Gossipsub is an implementation of pubsub based on meshsub and floodsub. You can read the specification [here](https://github.com/libp2p/specs/tree/master/pubsub/gossipsub).

`libp2p-gossipsub` currently implements the [`v1.1`](https://github.com/libp2p/specs/blob/master/pubsub/gossipsub/gossipsub-v1.1.md) of the spec.

## Install

`npm install libp2p-gossipsub`

## Usage

```javascript
const Gossipsub = require('libp2p-gossipsub')

const gsub = new Gossipsub(libp2p, options)

await gsub.start()

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

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

## API

### Create a gossipsub implementation

```js
const options = {…}
const gossipsub = new Gossipsub(libp2p, options)
```

Options is an optional object with the following key-value pairs:

* **`emitSelf`**: boolean identifying whether the node should emit to self on publish, in the event of the topic being subscribed (defaults to **false**).
* **`gossipIncoming`**: boolean identifying if incoming messages on a subscribed topic should be automatically gossiped (defaults to **true**).
* **`fallbackToFloodsub`**: boolean identifying whether the node should fallback to the floodsub protocol, if another connecting peer does not support gossipsub (defaults to **true**).
* **`floodPublish`**: boolean identifying if self-published messages should be sent to all peers, (defaults to **true**).
* **`doPX`**: boolean identifying whether PX is enabled; this should be enabled in bootstrappers and other well connected/trusted nodes (defaults to **false**).
* **`msgIdFn`**: a function with signature `(message) => string` defining the message id given a message, used internally to deduplicate gossip (defaults to `(message) => message.from + message.seqno.toString('hex')`)
* **`signMessages`**: boolean identifying if we want to sign outgoing messages or not (default: `true`)
* **`strictSigning`**: boolean identifying if message signing is required for incoming messages or not (default: `true`)
* **`messageCache`**: optional, a customized `MessageCache` instance, see the implementation for the interface.
* **`scoreParams`**: optional, a customized peer score parameters Object.
* **`scoreThresholds`**: optional, a customized peer score thresholds Object.
* **`directPeers`**: optional, an array of `AddrInfo` of peers with which we will maintain direct connections.

For the remaining API, see [libp2p-interfaces/pubsub](https://github.com/libp2p/js-libp2p-interfaces/tree/master/packages/interfaces/src/pubsub).

## Contribute

This module is actively under development. Please check out the issues and submit PRs!

## License

MIT © ChainSafe Systems