From 9175a81fb0a71b92b638c12decd73750918248ea Mon Sep 17 00:00:00 2001
From: Markus Tacker <m@coderbyheart.com>
Date: Thu, 18 Jul 2019 18:59:48 +0200
Subject: [PATCH] feat(connect): use stable prot for builtin server

---
 scripts/connect.ts              |  5 +++++
 scripts/device/portForDevice.ts | 11 +++++++++++
 scripts/device/ui-server.ts     |  4 +++-
 3 files changed, 19 insertions(+), 1 deletion(-)
 create mode 100644 scripts/device/portForDevice.ts

diff --git a/scripts/connect.ts b/scripts/connect.ts
index f53f0d20..d5d74a77 100644
--- a/scripts/connect.ts
+++ b/scripts/connect.ts
@@ -10,6 +10,10 @@ import { uiServer } from './device/ui-server'
  */
 const main = async (args: { deviceId: string }) => {
 	const clientId = args.deviceId
+	if (!clientId || !clientId.length) {
+		throw new Error('Must provide a device id!')
+	}
+	console.log(chalk.magenta('Fetching IoT endpoint address ...'))
 	const { endpointAddress } = await new Iot({
 		region: process.env.AWS_DEFAULT_REGION,
 	})
@@ -54,6 +58,7 @@ const main = async (args: { deviceId: string }) => {
 
 		connection.register(clientId, {}, async () => {
 			await uiServer({
+				deviceId: clientId,
 				onUpdate: update => {
 					console.log({ clientId, state: { state: { reported: update } } })
 					connection.update(clientId, { state: { reported: update } })
diff --git a/scripts/device/portForDevice.ts b/scripts/device/portForDevice.ts
new file mode 100644
index 00000000..01e891db
--- /dev/null
+++ b/scripts/device/portForDevice.ts
@@ -0,0 +1,11 @@
+/**
+ * Calculates a stable port number based on the device id
+ */
+export const portForDevice = ({ deviceId }: { deviceId: string }): number => {
+	let hash = 0
+	for (let i = 0; i < deviceId.length; i++) {
+		hash = (hash << 5) - hash + deviceId.charCodeAt(i)
+		hash |= 0 // Convert to 32bit integer
+	}
+	return 1024 + Math.round((hash / Math.pow(2, 31)) * (65535 - 1024))
+}
diff --git a/scripts/device/ui-server.ts b/scripts/device/ui-server.ts
index 5221d45d..3008eb73 100644
--- a/scripts/device/ui-server.ts
+++ b/scripts/device/ui-server.ts
@@ -2,11 +2,13 @@ import * as path from 'path'
 import * as http from 'http'
 import { promises as fs } from 'fs'
 import chalk from 'chalk'
+import { portForDevice } from './portForDevice'
 
 export const uiServer = async (args: {
+	deviceId: string
 	onUpdate: (update: object) => void
 }) => {
-	const port = 1024 + Math.round(Math.random() * (65535 - 1024))
+	const port = portForDevice({ deviceId: args.deviceId })
 	const uiPage = await fs.readFile(
 		path.resolve(process.cwd(), 'data', 'device-ui.html'),
 		'utf-8',