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server.js
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server.js
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var http = require('http')
var https = require('https')
var corsify = require('corsify')
var collect = require('stream-collector')
var pump = require('pump')
var iterate = require('random-iterate')
var limiter = require('size-limit-stream')
var eos = require('end-of-stream')
var origins = require('./origins.json') || {}
var flushHeaders = function (res) {
if (res.flushHeaders) {
res.flushHeaders()
} else {
if (!res._header) res._implicitHeader()
res._send('')
}
}
module.exports = function (opts) {
var channels = {}
var maxBroadcasts = (opts && opts.maxBroadcasts) || Infinity
var subs = 0
console.log('Imported origins:', origins)
var get = function (channel) {
if (channels[channel]) return channels[channel]
var sub = {name: channel, subscribers: [], heartbeat: null}
sub.heartbeat = setInterval(heartbeater(sub), 30 * 1000)
channels[channel] = sub
return channels[channel]
}
var getOrigin = function (req, res) {
return (origins.allowed && origins.allowed.includes(req.headers.origin)) ? req.headers.origin : ''
}
var cors = corsify({
'getOrigin': getOrigin,
'Access-Control-Allow-Methods': 'GET, POST',
'Access-Control-Allow-Headers': 'X-Requested-With, X-HTTP-Method-Override, Content-Type, Accept, Authorization'
})
var onRequest = cors(function (req, res) {
if (req.url === '/stats') {
res.setHeader('Content-Type', 'application/json; charset=utf-8')
flushHeaders(res)
res.end(JSON.stringify({name: 'signalhub', version: require('./package').version, subscribers: subs}, null, 2) + '\n')
return
}
if (req.url.slice(0, 4) !== '/v1/') {
res.statusCode = 404
res.end()
return
}
var name = req.url.slice(4).split('?')[0]
if (req.method === 'POST') {
res.setHeader('X-Accel-Buffering', 'no')
collect(pump(req, limiter(2048 * 1024)), function (err, data) {
if (err) return res.end()
if (!channels[name]) return res.end()
var channel = get(name)
server.emit('publish', channel.name, data)
data = Buffer.concat(data).toString()
var ite = iterate(channel.subscribers)
var next
var cnt = 0
while ((next = ite()) && cnt++ < maxBroadcasts) {
next.write('data: ' + data + '\n\n')
}
res.end()
})
return
}
if (req.method === 'GET') {
res.setHeader('Content-Type', 'text/event-stream; charset=utf-8')
res.setHeader('Cache-Control', 'no-cache')
// Disable NGINX request buffering
res.setHeader('X-Accel-Buffering', 'no')
var app = name.split('/')[0]
var channelNames = name.slice(app.length + 1)
channelNames.split(',').forEach(function (channelName) {
var channel = get(app + '/' + channelName)
server.emit('subscribe', channel.name)
channel.subscribers.push(res)
subs++
eos(res, function () {
subs--
var i = channel.subscribers.indexOf(res)
if (i > -1) channel.subscribers.splice(i, 1)
if (!channel.subscribers.length && channel === channels[channel.name]) {
clearInterval(channel.heartbeat)
delete channels[channel.name]
}
})
})
flushHeaders(res)
return
}
res.statusCode = 404
res.end()
})
var useHttps = !!(opts && opts.key && opts.cert)
var server = useHttps ? https.createServer(opts) : http.createServer()
server.on('request', onRequest)
server.on('close', function () {
var names = Object.keys(channels)
for (var i = 0; i < names.length; i++) {
clearInterval(channels[names[i]].heartbeat)
}
})
return server
}
function heartbeater (sub) {
return function () {
for (var i = 0; i < sub.subscribers.length; i++) {
sub.subscribers[i].write(':heartbeat signal\n\n')
}
}
}