shh-signal

Decentralized signalling for simple-peer using the Ethereum Whisper protocol.

Still an open research project, but it works! If you have a local node, try the demo!

Features

• All signalling data is sent over Whisper. Only STUN servers are used.
• Video, voice, data and all the features of WebRTC work as normal.
• Adapts almost all client features from simple-signal.

Install

With Browserify:

npm install shh-signal --save

Without Browserify:

<script src="dist/shh-signal-client.js"></script>

You also need access to the global Web3 object. shh-signal is currently only tested with the version in dist/web3.min.js.

You will also need a local Ethereum node with Websockets JSON-RPC and Whisper enabled.

Example

A common signaling scheme is to connect two clients by having one client "call" the ID of another.

Client:

const web3 = new Web3(new Web3.providers.WebsocketProvider('ws://localhost:8546')) // setup web3
const signalClient = new ShhSignalClient(web3) // setup shh-signal

const allIDs = []
signalClient.on('discover', async (newID) => {
	allIDs.push(newID)

  const id = await promptUserForID(allIDs) // Have the user choose an ID to connect to (you define this)
  const { peer } = await signalClient.connect(id) // connect to target client
  peer // this is a fully-signaled simple-peer object (initiator side)
})

signalClient.on('request', async (request) => {
  const { peer } = await request.accept() // Accept the incoming request
  peer // this is a fully-signaled simple-peer object (non-initiator side)
})

See example.js for a more comprehensive example.

Client API

signalClient = new ShhSignalClient(web3, [options])

Create a new signalling client.

Required web3 is a web3 instance with a provider that supports both Whisper and subscriptions (such as a WebsocketProvider connected to a local geth node started with the --shh option).

Options:

• connectionTimeout: number = 10000: Defines the time to wait to establish a connection.
• roomPassword": string = "": A secret passphrase used to encrypt connection messages.

signalClient.id

The identifying string for this client's socket. null until discovery completes. Consists of 2 public keys pubKey and sig, used for encryption and signing respectively.

signalClient.discover(discoveryData)

Initiate discovery.

discoveryData is any discovery data to be sent to all peers with the room password.

{ peer, metadata } = await signalClient.connect(id, [metadata], [peerOptions])

Request to connect to another client. Returns a Promise.

id is the signalClient.id of the other client.

Optional metadata is any serializable object to be passed along with the request.

Optional peerOptions are the options to be passed to the SimplePeer constructor.

signalClient.on('discover', function (remoteID, discoveryData) {})

Fired when the client has discovered a remote peer with the room password, or that peer has restarted discovery.

remoteID is the remote ID of the new peer.

discoveryData is any additional data that has been passed by the remote peer.

signalClient.on('request', function (request) {})

Fired on receiving a request to connect from another client.

request.initiator

The id of the remote client's socket.

request.metadata

Any additional metadata passed by the requesting client.

{ peer, metadata } = await request.accept([metadata], [peerOptions])

Accept the request to connect. Not calling this method will ignore the request. Returns a Promise.

metadata is any serializable object to be passed along with the answer.

peerOptions are the options to be passed to the SimplePeer constructor.

Promise will reject if the other side calls reject().

request.reject([metadata])

Rejects the request to connect. Not calling this method will ignore the request.

metadata is any serializable object to be passed along with the rejection.

signalClient.peers()

List all currently connecting/connected peers. Returns an array of SimplePeer objects.

FAQ

How do I setup the local Ethereum Node?

1. Download Grid: https://grid.ethereum.org/#downloads
2. Install and launch Grid.
3. Go to Geth > Settings and enable Use custom flags.
4. Add these flags to enable Websockets and Whisper:

--ws --wsorigins=* --shh

5. Start Geth and wait for the node to sync.
6. Done! You can now use this library to connect to everyone else on the Ethereum Whisper network!

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