sse.js

/*jshint globalstrict: true, node: true, trailing:true, unused:true */

'use strict';

var util = require('util');

module.exports = function SSEFeed() {
    this.subscribers = [];
    this.id = 0;
    return this;
};

SSEFeed.prototype.send = function(res, type, data) {
    res.write(util.format('id: %d\nevent: %s\ndata: %j\n\n',
                          this.id, type, data));
    res.flush();
};

SSEFeed.protoype.subscribe = function() {
    return function(req, res, next) {
        this.subscribers.push(res);
        req.socket.setTimeout(Infinity);
        res.writeHead(200, {
            'Content-Type': 'text/event-stream',
            'Cache-Control': 'no-cache',
            'Connection': 'keep-alive'
        });
        req.on('close', function() {
            this.subscribers.splice(this.subscribers.indexOf(res), 1);
        });
        return next();
    };
};

SSEFeed.prototype.emit = function(type, data) {
    this.id++;
    this.subscribers.forEach(function(subscriber) {
        this.send(subscriber, type, data);
    }.bind(this));
};

/* Local Variables:  */
/* mode:javascript   */
/* comment-column:0  */
/* js-indent-level:4 */
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