index.js

const http = require('http')
const httpProxy = require('http-proxy')
const express = require('express')
const request = require('request')
const httpsrv = require('httpsrv')
const fs = require('fs')
const SECRET = /rpc-secret=(.*)/.exec(
	fs.readFileSync('aria2c.conf', 'utf-8')
)[1]
const ENCODED_SECRET = Buffer.from(SECRET).toString('base64')

const PORT = process.env.PORT || 1234
const app = express()
const proxy = httpProxy.createProxyServer({
	target: 'ws://127.0.0.1:6800',
	ws: true
})
const server = http.createServer(app)

// Proxy websocket
server.on('upgrade', (req, socket, head) => {
	proxy.ws(req, socket, head)
})

// Handle normal http traffic
app.use('/jsonrpc', (req, res) => {
	req.pipe(request('http://127.0.0.1:6800/jsonrpc')).pipe(res)
})
app.use(
	'/downloads/' + ENCODED_SECRET,
	httpsrv({
		basedir: __dirname + '/downloads'
	})
)
app.use('/ariang', express.static(__dirname + '/ariang'))
app.get('/', (req, res) => {
	res.send(`
<label for="secret">Enter your aria2 secret:</label>
<input id="secret" type="password">
<button id="panel">Go to AriaNg panel</button>
<button id="downloads">View downloaded files</button>
<script>
panel.onclick=function(){
	open('/ariang/#!/settings/rpc/set/wss/'+location.hostname+'/443/jsonrpc/'+btoa(secret.value),'_blank')
}
downloads.onclick=function(){
	open('/downloads/'+btoa(secret.value)+'/')
}
</script>
`)
})
server.listen(PORT, () => console.log(`Listening on http://127.0.0.1:${PORT}`))

if (process.env.HEROKU_APP_NAME) {
	const readNumUpload = () =>
		new Promise((res, rej) =>
			fs.readFile('numUpload', 'utf-8', (err, text) =>
				err ? rej(err) : res(text)
			)
		)
	const APP_URL = `https://${process.env.HEROKU_APP_NAME}.herokuapp.com`
	const preventIdling = () => {
		request.post(
			'http://127.0.0.1:6800/jsonrpc',
			{
				json: {
					jsonrpc: '2.0',
					method: 'aria2.getGlobalStat',
					id: 'preventIdling',
					params: [`token:${SECRET}`]
				}
			},
			async (err, resp, body) => {
				console.log('preventIdling: getGlobalStat response', body)
				const { numActive, numWaiting } = body.result
				const numUpload = await readNumUpload()
				console.log(
					'preventIdling: numbers',
					numActive,
					numWaiting,
					numUpload
				)
				if (
					parseInt(numActive) +
						parseInt(numWaiting) +
						parseInt(numUpload) >
					0
				) {
					console.log('preventIdling: make request to prevent idling')
					request(APP_URL)
				}
			}
		)
		setTimeout(preventIdling, 15 * 60 * 1000) // 15 min
	}
	preventIdling()
}