eventsource

W3C compliant EventSource client for Node.js

EventSource

This library implements the EventSource client for Node.js. The API aims to be W3C compatible.

npm install eventsource
var EventSource = require('eventsource');
 
var es = new EventSource('http://demo-eventsource.rhcloud.com/');
es.onmessage = function(e) {
  console.log(e.data);
};
es.onerror = function() {
  console.log('ERROR!');
};

See the spec for API docs.

See https://github.com/einaros/sse-example

You can define custom HTTP headers for the initial HTTP request. This can be useful for e.g. sending cookies or to specify an initial Last-Event-ID value.

HTTP headers are defined by assigning a headers attribute to the optional eventSourceInitDict argument:

var eventSourceInitDict = {headers: {'Cookie': 'test=test'}};
var es = new EventSource(url, eventSourceInitDict);

By default, https requests that cannot be authorized will cause connection to fail and an exception to be emitted. You can override this behaviour:

var eventSourceInitDict = {rejectUnauthorized: false};
var es = new EventSource(url, eventSourceInitDict);

Note that for Node.js < v0.10.x this option has no effect - unauthorized HTTPS requests are always allowed.

Unauthorized and redirect error status codes (for example 401, 403, 301, 307) are available in the status property in the error event.

es.onerror = function (err) {
  if (err) {
    if (err.status === 401 || err.status === 403) {
      console.log('not authorized');
    }
  }
};