wip invalidate cache when room is finished

slug is another term in our app
this is the room id

src/backend/core/api/serializers.py

@@ -130,15 +130,16 @@ class RoomSerializer(serializers.ModelSerializer):
             del output["configuration"]
 
         if role is not None or instance.is_public:
-            slug = f"{instance.id!s}"
+            room_id = f"{instance.id!s}"
             username = request.query_params.get("username", None)
 
             output["livekit"] = {
                 "url": settings.LIVEKIT_CONFIGURATION["url"],
-                "room": slug,
+                "room": room_id,
                 "token": utils.generate_token(
-                    room=slug, user=request.user, username=username
+                    room=room_id, user=request.user, username=username
                 ),
+                "passphrase": utils.get_cached_passphrase(room_id)
             }
             
         output["is_administrable"] = is_admin

src/backend/core/api/viewsets.py

@@ -47,6 +47,8 @@ from core.recording.worker.mediator import (
 
 from . import permissions, serializers
 
+from livekit import api as livekit_api
+
 # pylint: disable=too-many-ancestors
 
 logger = getLogger(__name__)
@@ -210,6 +212,10 @@ class RoomViewSet(
         Allow unregistered rooms when activated.
         For unregistered rooms we only return a null id and the livekit room and token.
         """
+
+        # todo - determine whether encryption is needed store a shared secret in memory or in redis
+        # todo - check if a secret already exists, else create one.
+
         try:
             instance = self.get_object()
         except Http404:
@@ -343,6 +349,36 @@ class RoomViewSet(
             {"message": f"Recording stopped for room {room.slug}."}
         )
 
+    @decorators.action(
+        detail=False,
+        methods=["post"],
+        url_path="livekit-webhook",
+        permission_classes=[],
+        authentication_classes=[],
+    )
+    def handle_livekit_webhook(self, request, pk=None):  # pylint: disable=unused-argument
+        """Handle LiveKit webhook events."""
+        auth_token = request.headers.get("Authorization")
+        if not auth_token:
+            return drf_response.Response(
+                {"error": "Missing LiveKit authentication token"},
+                status=drf_status.HTTP_401_UNAUTHORIZED
+            )
+
+        token_verifier = livekit_api.TokenVerifier()
+        webhook_receiver = livekit_api.WebhookReceiver(token_verifier)
+
+        webhook_data = webhook_receiver.receive(request.body.decode("utf-8"), auth_token)
+
+        # Todo - livekit triggers a webhook for all events, see if we can restrict webhook to a limited number of events.
+        # Todo - handle Egress stopped / aborted events.
+
+        if webhook_data.event == "room_finished":
+            room_id = webhook_data.room.name
+            utils.clear_cache_passphrase(room_id)
+
+        return drf_response.Response({"message": f"Event processed"})
+
 
 class ResourceAccessListModelMixin:
     """List mixin for resource access API."""

src/backend/core/utils.py

@@ -14,6 +14,47 @@ from django.conf import settings
 
 from livekit.api import AccessToken, VideoGrants
 
+import secrets
+import string
+
+from django.core.cache import cache
+from cryptography.fernet import Fernet
+
+import base64
+
+
+def generate_random_passphrase(length=26):
+    """Generate a random passphrase using letters and digits"""
+    alphabet = string.ascii_letters + string.digits
+    return ''.join(secrets.choice(alphabet) for _ in range(length))
+
+
+def build_room_passphrase_key(room_id: str) -> str:
+    """Build cache key for room passphrase."""
+    return f"room_passphrase:{room_id}"
+
+def get_cached_passphrase(room_id: str) -> str:
+    """Get or generate encrypted passphrase for a room.
+
+    Retrieves existing passphrase from cache or generates,
+    encrypts and caches a new one if not found.
+    """
+    cypher = Fernet(settings.PASSPHRASE_ENCRYPTION_KEY.encode())
+    cache_key = build_room_passphrase_key(room_id)
+    encrypted_passphrase = cache.get(cache_key)
+
+    if encrypted_passphrase is None:
+        passphrase = generate_random_passphrase()
+        encrypted_passphrase = cypher.encrypt(passphrase.encode()).decode()
+        cache.set(cache_key, encrypted_passphrase, timeout=86400)  # 24 hours
+        return passphrase
+
+    return cypher.decrypt(encrypted_passphrase.encode()).decode()
+
+def clear_room_passphrase(room_id: str) -> None:
+    """Remove room passphrase from cache."""
+    cache.delete(build_room_passphrase_key(room_id))
+
 
 def generate_color(identity: str) -> str:
     """Generates a consistent HSL color based on a given identity string.

src/backend/meet/settings.py

@@ -483,6 +483,8 @@ class Base(Configuration):
     )
     BREVO_API_CONTACT_ATTRIBUTES = values.DictValue({"VISIO_USER": True})
 
+    PASSPHRASE_ENCRYPTION_KEY = values.Value(environ_name="PASSPHRASE_ENCRYPTION_KEY", environ_prefix=None)
+
     # pylint: disable=invalid-name
     @property
     def ENVIRONMENT(self):

src/frontend/src/features/rooms/api/ApiRoom.ts

@@ -8,6 +8,7 @@ export type ApiRoom = {
     url: string
     room: string
     token: string
+    passphrase: string
   }
   configuration?: {
     [key: string]: string | number | boolean

src/frontend/src/features/rooms/components/Conference.tsx

@@ -1,8 +1,13 @@
-import { useEffect, useMemo, useState } from 'react'
+import { useEffect, useMemo, useRef, useState } from 'react'
 import { useQuery } from '@tanstack/react-query'
 import { useTranslation } from 'react-i18next'
 import { LiveKitRoom, type LocalUserChoices } from '@livekit/components-react'
-import { Room, RoomOptions } from 'livekit-client'
+import {
+  Room,
+  RoomOptions,
+  ExternalE2EEKeyProvider,
+  DeviceUnsupportedError,
+} from 'livekit-client'
 import { keys } from '@/api/queryKeys'
 import { queryClient } from '@/api/queryClient'
 import { Screen } from '@/layout/Screen'
@@ -17,6 +22,9 @@ import { VideoConference } from '../livekit/prefabs/VideoConference'
 import posthog from 'posthog-js'
 import { css } from '@/styled-system/css'
 
+// todo - release worker when quitting the room, same for the key provider?
+// todo - check, seems the demo app from livekit trigger the web worker twice because of re-rendering
+
 export const Conference = ({
   roomId,
   userConfig,
@@ -63,12 +71,49 @@ export const Conference = ({
     retry: false,
   })
 
+  const e2eeEnabled = true
+
+  const workerRef = useRef<Worker | null>(null)
+  const keyProvider = useRef<any | null>(null)
+
+  const getKeyProvider = () => {
+    if (!keyProvider.current && typeof window !== 'undefined') {
+      keyProvider.current = new ExternalE2EEKeyProvider()
+    }
+    return keyProvider.current
+  }
+
+  const getWorker = () => {
+    if (!e2eeEnabled) {
+      return
+    }
+    if (!workerRef.current && typeof window !== 'undefined') {
+      workerRef.current = new Worker(
+        new URL('livekit-client/e2ee-worker', import.meta.url)
+      )
+    }
+    return workerRef.current
+  }
+
+  const e2eePassphrase = data?.livekit?.passphrase
+
+  const [e2eeSetupComplete, setE2eeSetupComplete] = useState(false)
+
   const roomOptions = useMemo((): RoomOptions => {
+    const worker = getWorker()
+    const keyProvider = getKeyProvider()
+
+    // todo - explain why
+    const videoCodec = e2eeEnabled ? undefined : 'vp9'
+    const e2ee = e2eeEnabled ? { keyProvider, worker } : undefined
+
     return {
       adaptiveStream: true,
       dynacast: true,
       publishDefaults: {
-        videoCodec: 'vp9',
+        // todo - explain why
+        red: !e2eeEnabled,
+        videoCodec,
       },
       videoCaptureDefaults: {
         deviceId: userConfig.videoDeviceId ?? undefined,
@@ -76,12 +121,35 @@ export const Conference = ({
       audioCaptureDefaults: {
         deviceId: userConfig.audioDeviceId ?? undefined,
       },
+      e2ee,
     }
     // do not rely on the userConfig object directly as its reference may change on every render
   }, [userConfig.videoDeviceId, userConfig.audioDeviceId])
 
   const room = useMemo(() => new Room(roomOptions), [roomOptions])
 
+  useEffect(() => {
+    console.log('enter', e2eePassphrase)
+    if (e2eePassphrase) {
+      const keyProvider = getKeyProvider()
+      keyProvider
+        .setKey(e2eePassphrase)
+        .then(() => {
+          room.setE2EEEnabled(true).catch((e) => {
+            if (e instanceof DeviceUnsupportedError) {
+              alert(
+                `You're trying to join an encrypted meeting, but your browser does not support it. Please update it to the latest version and try again.`
+              )
+              console.error(e)
+            } else {
+              throw e
+            }
+          })
+        })
+        .then(() => setE2eeSetupComplete(true))
+    }
+  }, [room, e2eePassphrase])
+
   const [showInviteDialog, setShowInviteDialog] = useState(mode === 'create')
 
   const { t } = useTranslation('rooms')
@@ -102,6 +170,10 @@ export const Conference = ({
     peerConnectionTimeout: 60000, // Default: 15s. Extended for slow TURN/TLS negotiation
   }
 
+  const handleEncryptionError = () => {
+    console.log('error')
+  }
+
   return (
     <QueryAware status={isFetchError ? createStatus : fetchStatus}>
       <Screen header={false} footer={false}>
@@ -109,13 +181,14 @@ export const Conference = ({
           room={room}
           serverUrl={data?.livekit?.url}
           token={data?.livekit?.token}
-          connect={true}
+          connect={e2eeSetupComplete}
           audio={userConfig.audioEnabled}
           video={userConfig.videoEnabled}
           connectOptions={connectOptions}
           className={css({
             backgroundColor: 'primaryDark.50 !important',
           })}
+          onEncryptionError={handleEncryptionError}
         >
           <VideoConference />
           {showInviteDialog && (

src/frontend/src/features/rooms/livekit/components/ParticipantTile.tsx

@@ -15,8 +15,9 @@ import {
   VideoTrack,
   TrackRefContext,
   ParticipantContextIfNeeded,
+  useIsSpeaking,
 } from '@livekit/components-react'
-import React from 'react'
+import React, { useEffect } from 'react'
 import {
   isTrackReference,
   isTrackReferencePinned,

src/helm/env.d/dev/values.livekit.yaml.gotmpl

@@ -17,6 +17,10 @@ livekit:
     udp_port: 443
     domain: livekit.127.0.0.1.nip.io
     loadBalancerAnnotations: {}
+  webhook:
+    api_key: devkey
+    urls:
+      - https://meet.127.0.0.1.nip.io/api/v1.0/rooms/livekit-webhook/
 
 
 loadBalancer:

src/helm/env.d/dev/values.meet.yaml.gotmpl

@@ -61,6 +61,7 @@ backend:
     RECORDING_STORAGE_EVENT_TOKEN: password
     SUMMARY_SERVICE_ENDPOINT: http://meet-summary:80/api/v1/tasks/
     SUMMARY_SERVICE_API_TOKEN: password
+    PASSPHRASE_ENCRYPTION_KEY: lT3cX5dzFhCe-9xNjXUiTCX00r2ZgHgGUJKO66x-QIo=
 
 
   migrate: