Web Client

A static site served by nginx. It provides the interviewer's console and a browser-based participant view that doubles as a non-VR fallback and as the easiest way to test a deployment.

Source lives in this repository, under website/.

There is no server-side logic - nginx serves files, and everything happens in the browser against Janus.

Routes

Route	Serves	Role
/	Token entry page	Separate participant and interviewer forms
/interview?ID=<token>	Participant view	INTERVIEW_ROLE = 'interviewee'
/interviewer?ID=<token>	Interviewer console	INTERVIEW_ROLE = 'interviewer'
/chat?ID=<token>	Standalone chat
/demos/	Stock Janus demos	Debugging - echotest is useful for isolating a client media problem

Both interview routes accept ID or room. Without one, the page redirects to /. The token is converted to a Janus room ID by roomIdFromString() in js/state.js - which must stay identical to the VR client's version. See Token and room derivation.

Features

Feature	Available to	Notes
Pre-interview device check	both	Camera/mic preview and device selection before joining
Device switching	both	Mid-session, without rejoining
Virtual background	both	Interviewer defaults to office, participant to none
Chat	both	Over the textroom data channel
Answer options	interviewer → participant	Pushed live; the participant's response is logged
Gaze overlay	interviewer	Live view of participant gaze
Follow-up prompts	interviewer
Recording control	interviewer	Toggles server-side recording; participant sees an indicator
Diagnostics	both	Connection state and statistics

Configuration

Everything deployment-specific is in janus-html/settings.js. Because it is static, changing it means rebuilding the image - there is no runtime configuration.

server = [ "wss://janus.example.org", "/janus" ];

iceServers = [
    { urls: "turn:turn.example.org:3478",               username: "<user>", credential: "<password>" },
    { urls: "turn:turn.example.org:3478?transport=tcp", username: "<user>", credential: "<password>" },
    { urls: "stun:stun1.l.google.com:3478" }
];

These credentials are public by construction

settings.js is downloaded by every browser that opens the page. TURN credentials placed here are readable by anyone. Treat them as published, rotate them, and read coturn security.

Building

docker compose builds this image itself from ./website - there is nothing to publish or pin. Edit website/janus-html/settings.js, then:

docker compose build website
docker compose up -d website

The image is nginx:alpine with a custom config (website/nginx.conf) providing the pretty routes and adding .mjs and .wasm MIME types - the latter is needed by the virtual background.

Known issue: answer options occasionally not arriving

Symptom: the interviewer pushes answer options and they never appear for the participant, while audio and video continue working normally.

That selectivity is the diagnostic. Audio, video and the control channel share the same network path and TURN server, so a fault affecting only one of them is not a network fault. The textroom needs several extra round trips that media does not - SCTP association, then create, then join - and it previously ran under a hard 12-second deadline that discarded all progress on expiry and restarted ICE from zero. On a good network that never fires; on a marginal one it is a coin flip.

Client-side fixes have shipped: the deadline behaviour was reworked, and recording state is now re-broadcast on a heartbeat instead of sent once.

One server-side item remains open

Widening Janus's rtp_port_range was identified as still needed, so that one struggling session cannot degrade others. See Janus configuration.

Full analysis: Web Client Reliability.