performance improvements

.github/renovate.json

@@ -0,0 +1,16 @@
+{
+  "$schema": "https://docs.renovatebot.com/renovate-schema.json",
+  "extends": ["config:base"],
+  "labels": ["dependencies"],
+  "rangeStrategy": "bump",
+  "dependencyDashboard": false,
+  "timezone": "Pacific/Auckland",
+  "schedule": ["every 2 weeks"],
+  "packageRules": [
+    {
+      "matchDepTypes": ["devDependencies"],
+      "groupName": "devDependencies",
+      "automerge": true
+    }
+  ]
+}

README.md

@@ -3,6 +3,7 @@
 [![Build Status](https://github.com/k-yle/rtsp-relay/workflows/build/badge.svg)](https://github.com/k-yle/rtsp-relay/actions)
 [![Coverage Status](https://coveralls.io/repos/github/k-yle/rtsp-relay/badge.svg?branch=main)](https://coveralls.io/github/k-yle/rtsp-relay?branch=main)
 [![npm version](https://badge.fury.io/js/rtsp-relay.svg)](https://badge.fury.io/js/rtsp-relay)
+![npm bundle size](https://img.shields.io/bundlephobia/minzip/rtsp-relay)
 
 This module allows you to view an RTSP stream in your web browser using an existing express.js server.
 
@@ -58,6 +59,24 @@ app.listen(2000);
 
 Open [http://localhost:2000](http://localhost:2000) in your web browser.
 
+### Usage with many cameras
+
+If you have hundreds of cameras and don't want to define a seperate route for each one, you can use a dynamic URL:
+
+```js
+app.ws('/api/stream/:cameraIP', (ws, req) =>
+  proxy({
+    url: `rtsp://${req.params.cameraIP}:554/feed`,
+  })(ws),
+);
+```
+
+### Usage with many clients
+
+You may see a `MaxListenersExceededWarning` if the relay is re-transmitting 10+ streams at once, or if 10+ clients are watching.
+
+This is expected, and you can silence the warning by adding `process.setMaxListeners(0);` to your code.
+
 ## Contributing
 
 We have end-to-end tests to ensure that the module actually works. These tests spin up a RTSP server using [aler9/rtsp-simple-server](https://github.com/aler9/rtsp-simple-server) and create several different streams for testing. These tests are far from complete.

index.js

@@ -13,6 +13,7 @@ const ps = require('ps-node');
  *
  * @typedef {import("express").Application} Application
  * @typedef {import("ws")} WebSocket
+ * @typedef {import("child_process").ChildProcessWithoutNullStreams} Stream
  */
 
 class InboundStreamWrapper {
@@ -25,9 +26,9 @@ class InboundStreamWrapper {
       [
         '-i',
         url,
-        '-f',
+        '-f', // force format
         'mpegts',
-        '-codec:v',
+        '-codec:v', // specify video codec (MPEG1 required for jsmpeg)
         'mpeg1video',
         '-r',
         '30', // 30 fps. any lower and the client can't decode it
@@ -61,7 +62,7 @@ class InboundStreamWrapper {
   get(options) {
     this.verbose = options.verbose;
     if (!this.stream) this.start(options);
-    return this.stream;
+    return /** @type {Stream} */ (this.stream);
   }
 
   /** @param {number} clientsLeft */
@@ -89,6 +90,13 @@ module.exports = (app) => {
   if (!wsInstance) wsInstance = ews(app);
   const wsServer = wsInstance.getWss();
 
+  /**
+   * This map stores all the streams in existance, keyed by the URL.
+   * This means we only ever create one InboundStream per URL.
+   * @type {{ [url: string]: InboundStreamWrapper }}
+   */
+  const Inbound = {};
+
   return {
     killAll() {
       ps.lookup({ command: 'ffmpeg' }, (err, list) => {
@@ -101,12 +109,13 @@ module.exports = (app) => {
 
     /** @param {Options} props */
     proxy({ url, additionalFlags = [], verbose }) {
-      const Inbound = new InboundStreamWrapper();
+      if (!url) throw new Error('URL to rtsp stream is required');
+
+      // TODO: node15 use ||=
+      if (!Inbound[url]) Inbound[url] = new InboundStreamWrapper();
 
       /** @param {WebSocket} ws */
       function handler(ws) {
-        if (!url) throw new Error('URL to rtsp stream is required');
-
         // these should be detected from the source stream
         const [width, height] = [0, 0];
 
@@ -117,18 +126,23 @@ module.exports = (app) => {
         ws.send(streamHeader, { binary: true });
 
         if (verbose) console.log('[rtsp-relay] New WebSocket Connection');
-        const streamIn = Inbound.get({ url, additionalFlags, verbose });
+
+        const streamIn = Inbound[url].get({ url, additionalFlags, verbose });
+
+        /** @param {Buffer} chunk */
+        function onData(chunk) {
+          if (ws.readyState === 1) ws.send(chunk);
+        }
+
         ws.on('close', () => {
           const c = wsServer.clients.size;
           if (verbose)
             console.log(`[rtsp-relay] WebSocket Disconnected ${c} left`);
-          Inbound.kill(c);
+          Inbound[url].kill(c);
+          streamIn.stdout.off('data', onData);
         });
 
-        // @ts-expect-error will fix later
-        streamIn.stdout.on('data', (data, opts) => {
-          if (ws.readyState === 1) ws.send(data, opts);
-        });
+        streamIn.stdout.on('data', onData);
       }
       return handler;
     },

package.json

@@ -1,6 +1,6 @@
 {
   "name": "rtsp-relay",
-  "version": "1.1.1",
+  "version": "1.1.2",
   "author": "Kyle Hensel",
   "license": "MIT",
   "description": "📽 Relay an RTSP stream through an existing express.js server",

test/setupTests.js

@@ -4,6 +4,13 @@ const { path: ffmpegPath } = require('@ffmpeg-installer/ffmpeg');
 const { join } = require('path');
 const rtspRelay = require('..');
 
+process.on('warning', (err) => {
+  if (err.name === 'MaxListenersExceededWarning') {
+    console.log(err.stack);
+    console.trace();
+  }
+});
+
 console.log(`Setting up RTSP server on ${process.platform} (${process.arch})`);
 
 const rtspServer = spawn(