From c77e5dee84e4c09bbb41e8dcb8fd63b96b7178c7 Mon Sep 17 00:00:00 2001
From: Allen Porter <allen.porter@gmail.com>
Date: Mon, 3 Oct 2022 18:10:57 -0700
Subject: [PATCH] Allow remote WebRTC playback using STUN server from RTSPtoWeb
 integration (#13942)

Co-authored-by: Bram Kragten <mail@bramkragten.nl>
---
 src/components/ha-web-rtc-player.ts | 37 +++++++++++++++++++++++++++--
 src/data/rtsp_to_webrtc.ts          | 10 ++++++++
 2 files changed, 45 insertions(+), 2 deletions(-)
 create mode 100644 src/data/rtsp_to_webrtc.ts

diff --git a/src/components/ha-web-rtc-player.ts b/src/components/ha-web-rtc-player.ts
index 3987ff918c..0e7d31bc3a 100644
--- a/src/components/ha-web-rtc-player.ts
+++ b/src/components/ha-web-rtc-player.ts
@@ -7,7 +7,9 @@ import {
   TemplateResult,
 } from "lit";
 import { customElement, property, state, query } from "lit/decorators";
+import { isComponentLoaded } from "../common/config/is_component_loaded";
 import { handleWebRtcOffer, WebRtcAnswer } from "../data/camera";
+import { fetchWebRtcSettings } from "../data/rtsp_to_webrtc";
 import type { HomeAssistant } from "../types";
 import "./ha-alert";
 
@@ -86,7 +88,8 @@ class HaWebRtcPlayer extends LitElement {
   private async _startWebRtc(): Promise<void> {
     this._error = undefined;
 
-    const peerConnection = new RTCPeerConnection();
+    const configuration = await this._fetchPeerConfiguration();
+    const peerConnection = new RTCPeerConnection(configuration);
     // Some cameras (such as nest) require a data channel to establish a stream
     // however, not used by any integrations.
     peerConnection.createDataChannel("dataSendChannel");
@@ -102,12 +105,25 @@ class HaWebRtcPlayer extends LitElement {
     );
     await peerConnection.setLocalDescription(offer);
 
+    let candidates = ""; // Build an Offer SDP string with ice candidates
+    const iceResolver = new Promise<void>((resolve) => {
+      peerConnection.addEventListener("icecandidate", async (event) => {
+        if (!event.candidate) {
+          resolve(); // Gathering complete
+          return;
+        }
+        candidates += `a=${event.candidate.candidate}\r\n`;
+      });
+    });
+    await iceResolver;
+    const offer_sdp = offer.sdp! + candidates;
+
     let webRtcAnswer: WebRtcAnswer;
     try {
       webRtcAnswer = await handleWebRtcOffer(
         this.hass,
         this.entityid,
-        offer.sdp!
+        offer_sdp
       );
     } catch (err: any) {
       this._error = "Failed to start WebRTC stream: " + err.message;
@@ -138,6 +154,23 @@ class HaWebRtcPlayer extends LitElement {
     this._peerConnection = peerConnection;
   }
 
+  private async _fetchPeerConfiguration(): Promise<RTCConfiguration> {
+    if (!isComponentLoaded(this.hass!, "rtsp_to_webrtc")) {
+      return {};
+    }
+    const settings = await fetchWebRtcSettings(this.hass!);
+    if (!settings || !settings.stun_server) {
+      return {};
+    }
+    return {
+      iceServers: [
+        {
+          urls: [`stun:${settings.stun_server!}`],
+        },
+      ],
+    };
+  }
+
   private _cleanUp() {
     if (this._remoteStream) {
       this._remoteStream.getTracks().forEach((track) => {
diff --git a/src/data/rtsp_to_webrtc.ts b/src/data/rtsp_to_webrtc.ts
new file mode 100644
index 0000000000..777d7147e4
--- /dev/null
+++ b/src/data/rtsp_to_webrtc.ts
@@ -0,0 +1,10 @@
+import { HomeAssistant } from "../types";
+
+export interface WebRtcSettings {
+  stun_server?: string;
+}
+
+export const fetchWebRtcSettings = async (hass: HomeAssistant) =>
+  hass.callWS<WebRtcSettings>({
+    type: "rtsp_to_webrtc/get_settings",
+  });