Arcus

Server-sent events (SSE) module for NodeJS.

Installation

Because this package is not in npmjs.org yet, it needs to be installed from this Github repo:

$ npm install --save arnellebalane/arcus

API

arcus inherits the prototype of EventEmitter.

• connect(req, res) => id: Enable Server-Sent Events (SSEs) on the given connection.

  • req: an http.IncomingMessage instance
  • res: an http.ServerResponse instance
  • returns an id, which is a uuid that identifies the connection

• disconnect(id): Send the disconnect event to the SSE client identified by the given id and then forget about it.

  • id: The uuid of the SSE connection to be disconnected

• send(id, options={}): Send data to an SSE client identified by the given uuid.

  • id: The uuid of the SSE client to send the data to.
  • options.event: The name for the server-sent event. Specifying this option will trigger the client-side EventSource's event listeners for the event of the same name, otherwise the message event.
  • options.data: The data that will be sent to the SSE client, and can be obtained from "e.data" in the client-side callbacks.

• event: 'connect': Emitted after successful connect() operation. Callback function receives the following arguments:

  • id: The uuid that identifies the new SSE connection

• event: 'disconnect': Emitted after successful disconnect() operation. Callback function receives the following arguments:

  • id: The uuid of the SSE connection that got disconnected

• event: 'send': Emitted after successful send() operation. Callback function receives the following arguments:

  • id: The uuid of the SSE connection where the data was sent to.
  • options: Same options object that got passed to the send function.

Usage Example

const arcus = require('arcus');

arcus.on('connect', (id) => {
    console.log(`Client "${id}" is now connected.`);
    arcus.send(id, 'You are now connected to Arcus!');
});

app.get('/stream', (req, res) => arcus.connect(req, res));

License

MIT License