[](http://standardjs.com/)
npm install signal-firepeerIds?
bash
npm install signal-fire
`
$3
#### Command-line usage
signal-fire is now also available as a command-line application. This allows you
to quickly start a signal-fire server instance with optional verbose output.
Currently there is no support for background jobs (i.e. a daemon), but this may
come in the future.
Install the package globally to access the cli:
`bash
npm i -g signal-fire
`
Next you can use signal-fire to start a server:
`bash
> signal-fire
signal-fire instance started on port 8080
press ctrl+c to stop
`
Use -h to view the help:
`bash
Usage: signal-fire [options]
Options:
-h, --help output usage information
-V, --version output the version number
-p, --port [port] Port to listen on [8080]
-v, --verbose Show verbose output
`
#### Setting up the server
The example below provides a simple example:
`js
// Require the server
const Server = require('signal-fire').Server
// Instantiate a new Server
const server = new Server({
// These options are passed directly to ws
port: 8080
})
server.on('add_peer', peer => {
console.log(Added peer with peerId ${peer.peerId})
})
server.on('remove_peer', peerId => {
console.log(Removed peer with peerId ${peerId})
})
server.start().then(() => {
console.log('Server started')
})
`
That's all there is to it!
If you want to use µWS instead, you can set it in the options:
`js
const Server = require('signal-fire').Server
const WebSocketServer = require('uws').Server
const server = new Server({
engine: WebSocketServer,
port: 8080
})
`
#### Communicating with the server
Smart move: You can use the signal-fire client as an easy to use
client which abstracts away the specifics of communicating with signal-fire and
the WebRTC set-up and handling.
Using the client is by no means a prerequisite; you can use the standard WebSocket
as well.
To keep everything as simple as possible, the message format of choice is JSON.
On the client side you can use WebSocket to connect to the server:
`js
// In the browser
// Connect to the server
const signalServer = new WebSocket('ws://example.com:8080')
signalServer.onopen = () => {
console.log('Connection established')
}
let myPeerId = null
signalServer.onmessage = (event) {
const msg = JSON.parse(event.data)
// The first message received will contain our unique peerId
if(myPeerId === null && msg.peerId) {
myPeerId = msg.peerId
}
// Now you can process the messages like you usually would
// when setting up a WebRTC peer-to-peer channel
}
`
In order to communicate with another peer, you only need to include receiverId in
your message, like so:
`js
// otherPeerId is the peerId of another client connected to the server
signalServer.send({
receiverId: otherPeerId,
key: 'value'
})
`
By adding the receiverId key to your outgoing messages the server will route
the messages to their intended destination (provided a peer with the provided
peerId is connected to the server as well).
Now you can use the channel to pass ICE candidates etc.
$3
If you want to run multiple instances of the server that can communicate with each
other, you can use signal-fire-relay. It works
with common pub/sub modules such as redis and mqtt.
#### Using the relay
A relay can be used to scale signal-fire. A relay is a module
that uses a publish-subscribe messaging channel to route messages between multiple
instances of the signaling server.
Any message meant for a peerId not on the local instance will be given to the relay.
Below is an example of using a relay with mqtt.
`js
const Server = require('signal-fire').Server
const Relay = require('signal-fire-relay').Relay
const client = require('mqtt').createClient()
const server = new Server({
port: 8080,
relay: new Relay(client)
})
server.start().then(() => {
console.log('Server started')
})
// ...
`
If you want to write your own relay, you can use the Redis relay as a reference
implementation.
Changelog
* v0.5.1
* Fix example and peerId (closes #4)
* v0.5.0
* Added CLI app and documentation
* v0.4.0
* Updated relay logic to use signal-fire-relay
* WebSocket engine is now selectable
* error is now re-emitted
* Several other fixes
* v0.3.0
* Changes to how relays work
* Added some basic error handling
* v0.2.0
* Exchange peerId for receiverId` in routing messages