sse-pusher
v1.1.1
Published
Simple server-sent events (SSE) for Connect and Express
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SSE-Pusher
Simple server-sent events (SSE) for Connect and Express.
Installation
$ npm install --save sse-pusher
API
var ssePusher = require('sse-pusher');
var push = ssePusher(); // instantiation variant 1
var push = ssePusher.create(); // instantiation variant 2
push([event,] data)
Pushes an optionally typed (i.e., using the event
parameter) event to all connected SSE clients.
Parameters:
event
- event type, must be a string;data
- event data, can be anything that can be serialized usingJSON.stringify()
. More precisely, anything that is not a string, number or boolean will be serialized usingJSON.stringify()
.
push.handler([mountPath])
Returns a function that can be used both as a Connect/Express middleware and an Express route handler.
Parameters:
mountPath
- path where the Connect/Express middleware shall be mounted (e.g.,/some/path
).
Usage
Server-side
First, you have to load the package a instantiate a new SSE-Pusher:
// load package:
var ssePusher = require('sse-pusher');
// instantiate a new SSE-Pusher:
var push = ssePusher();
Afterwards, you have to "wire" the SSE-Pusher with you HTTP framework of choice (i.e., Connect or Express):
var app = connect() || express();
// install the pusher as a Connect/Express middleware:
app.use(push.handler('/some/path')); // variant 1
app.use('/some/path', push.handler()); // variant 2
// install the pusher as an Express route handler:
app.get('/some/path', push.handler());
Finally, using push(event, data)
or push(data)
you can then start pushing data to connected SSE clients:
// push some data:
push('eventname', 'eventdata');
// push some data without specifying an event name:
push({some: 'data'});
Client-side
On the client (i.e., the Web browser) you may then listen to the server-side emitted messages using the following code:
var es = new EventSource('http://localhost:3000/some/path');
// when using push('hello') on the server:
es.onmessage = function (event) {
console.log(event.data); // logs 'hello'
};
// when using push('greeting', 'world') on the server:
es.addEventListener('greeting', function (event) {
console.log(event.data); // logs 'world'
});