ubuntu-based-kiosk/webui/server.js

'use strict';

// webui/server.js - Kiosk Web UI: browser-based config editor for Sites &
// Page Timing, Display & Interaction, and Password Protection & Lockout -
// the three Core Settings menus that are pure config.json read/write with
// no privileged system mutation involved (see menus/addon_webui.sh's
// header for why the rest of Core Settings/Addons/Advanced aren't here).
//
// No login of its own by design: Authelia runs elsewhere, and the admin
// site goes behind the user's own Caddy reverse proxy with Authelia
// forward-auth in front of it, the same way every other self-hosted app
// they run is protected. This process only binds where it's told to
// (BIND_ADDR/PORT below) and trusts whatever's in front of it.
//
// Runs as $KIOSK_USER (see the systemd unit menus/addon_webui.sh
// installs) - the same user Electron runs as, and the owner of
// config.json - so it never needs sudo.

const path = require('path');
const { execFile } = require('child_process');
const express = require('express');
const { loadConfig, saveConfig } = require('./lib/config');
const { ACTIONS } = require('./lib/actions');
const { startJob, getJob } = require('./lib/jobs');

const HELPER_PATH = process.env.HELPER_PATH || '/usr/local/bin/kiosk-webui-helper';
const SUDO_CMD = process.env.SUDO_CMD !== undefined ? process.env.SUDO_CMD : 'sudo';

const app = express();
app.use(express.json({ limit: '256kb' }));
app.use(express.static(path.join(__dirname, 'public')));

const SWIPE_MODES = ['dual', 'standard'];
const NAV_MODES = ['restricted', 'same-origin', 'open'];
const TIME_RE = /^([01]\d|2[0-3]):[0-5]\d$/;

// Same normalization rule as menus/sites.sh's sites_parse_url(): bare
// host -> https://, bare IPv4 -> http://, else passed through as-is.
function parseUrl(raw) {
    if (/^https?:\/\//.test(raw)) return raw;
    if (/^\d+\.\d+\.\d+\.\d+/.test(raw)) return `http://${raw}`;
    return `https://${raw}`;
}

function badRequest(res, message) {
    res.status(400).json({ error: message });
}

app.get('/api/config', (req, res) => {
    res.json(loadConfig());
});

app.put('/api/config', (req, res) => {
    const body = req.body && typeof req.body === 'object' ? req.body : {};
    const patch = {};

    if (body.swipeMode !== undefined) {
        if (!SWIPE_MODES.includes(body.swipeMode)) return badRequest(res, 'swipeMode must be "dual" or "standard"');
        patch.swipeMode = body.swipeMode;
    }
    if (body.allowNavigation !== undefined) {
        if (!NAV_MODES.includes(body.allowNavigation)) {
            return badRequest(res, 'allowNavigation must be "restricted", "same-origin", or "open"');
        }
        patch.allowNavigation = body.allowNavigation;
    }
    if (body.enablePauseButton !== undefined) patch.enablePauseButton = !!body.enablePauseButton;
    if (body.enableKeyboardButton !== undefined) patch.enableKeyboardButton = !!body.enableKeyboardButton;
    if (body.enableNavButton !== undefined) patch.enableNavButton = !!body.enableNavButton;

    let tabCount;
    if (body.tabs !== undefined) {
        if (!Array.isArray(body.tabs)) return badRequest(res, 'tabs must be an array');
        for (const t of body.tabs) {
            if (!t || typeof t.url !== 'string' || t.url.trim() === '') return badRequest(res, 'Every site needs a URL');
            const dur = Number(t.duration);
            if (!Number.isInteger(dur) || dur < -1 || dur > 86400) {
                return badRequest(res, 'Duration must be a whole number between -1 and 86400');
            }
        }
        patch.tabs = body.tabs.map((t) => ({ ...t, url: parseUrl(t.url.trim()) }));
        tabCount = patch.tabs.length;
    }

    if (body.homeTabIndex !== undefined) {
        const idx = Number(body.homeTabIndex);
        const count = tabCount !== undefined ? tabCount : loadConfig().tabs.length;
        if (!Number.isInteger(idx) || idx < -1 || idx >= count) return badRequest(res, 'homeTabIndex is out of range');
        patch.homeTabIndex = idx;
    }

    if (body.inactivityTimeoutMinutes !== undefined) {
        const min = Number(body.inactivityTimeoutMinutes);
        if (!Number.isInteger(min) || min < 1 || min > 240) return badRequest(res, 'Inactivity timeout must be 1-240 minutes');
        patch.inactivityTimeout = min * 60;
    }

    if (body.enablePasswordProtection !== undefined) patch.enablePasswordProtection = !!body.enablePasswordProtection;

    if (body.lockoutTimeoutMinutes !== undefined) {
        const min = Number(body.lockoutTimeoutMinutes);
        if (!Number.isInteger(min) || min < 0 || min > 1440) return badRequest(res, 'Lockout timeout must be 0-1440 minutes');
        patch.lockoutTimeout = min;
    }

    if (body.lockoutAtTime !== undefined) {
        if (body.lockoutAtTime !== '' && !TIME_RE.test(body.lockoutAtTime)) {
            return badRequest(res, 'lockoutAtTime must be HH:MM (24-hour) or empty');
        }
        patch.lockoutAtTime = body.lockoutAtTime;
    }

    if (body.requirePasswordOnBoot !== undefined) patch.requirePasswordOnBoot = !!body.requirePasswordOnBoot;

    if (body.newLockoutPassword !== undefined) {
        if (typeof body.newLockoutPassword !== 'string' || body.newLockoutPassword.length === 0) {
            return badRequest(res, 'Password cannot be empty');
        }
        patch.newLockoutPassword = body.newLockoutPassword;
    }

    // Mirrors action_enable_protection() always requiring a password up
    // front - lockout.sh has no path that enables protection without one.
    if (patch.enablePasswordProtection === true) {
        const hasNewPassword = typeof patch.newLockoutPassword === 'string' && patch.newLockoutPassword.length > 0;
        if (!hasNewPassword && !loadConfig().hasLockoutPassword) {
            return badRequest(res, 'Set a lockout password before enabling password protection');
        }
    }

    try {
        res.json(saveConfig(patch));
    } catch (e) {
        console.error('saveConfig failed:', e);
        res.status(500).json({ error: 'Failed to save configuration' });
    }
});

/* ---------------------------------------------------------------------- */
/* Addons: install/reconfigure via the allow-listed root helper           */
/* ---------------------------------------------------------------------- */

app.get('/api/actions', (req, res) => {
    const list = Object.entries(ACTIONS).map(([name, a]) => ({ name, label: a.label, fields: a.fields }));
    res.json(list);
});

app.get('/api/addons/status', (req, res) => {
    const cmd = SUDO_CMD || HELPER_PATH;
    const args = SUDO_CMD ? [HELPER_PATH, 'status_all'] : ['status_all'];
    execFile(cmd, args, { timeout: 10_000 }, (err, stdout, stderr) => {
        if (err) {
            console.error('status_all failed:', stderr || err.message);
            return res.status(500).json({ error: 'Could not read addon status' });
        }
        try {
            res.json(JSON.parse(stdout.trim()));
        } catch (e) {
            res.status(500).json({ error: 'Malformed status response' });
        }
    });
});

app.post('/api/actions/:name/run', (req, res) => {
    try {
        const job = startJob(req.params.name, req.body || {});
        res.json({ jobId: job.id, status: job.status, label: job.label });
    } catch (e) {
        res.status(e.status || 500).json({ error: e.message });
    }
});

app.get('/api/actions/jobs/:jobId', (req, res) => {
    const job = getJob(req.params.jobId);
    if (!job) return res.status(404).json({ error: 'Unknown job' });
    res.json({ id: job.id, name: job.name, label: job.label, status: job.status, exitCode: job.exitCode, log: job.log.join('') });
});

// Server-Sent Events: replays whatever's already logged, then streams
// new lines as they arrive, then a final `done` event - works whether
// the client connects before the job starts producing output or
// reconnects partway through (e.g. after a page reload).
app.get('/api/actions/jobs/:jobId/stream', (req, res) => {
    const job = getJob(req.params.jobId);
    if (!job) return res.status(404).end();

    res.writeHead(200, {
        'Content-Type': 'text/event-stream',
        'Cache-Control': 'no-cache',
        Connection: 'keep-alive',
    });

    if (job.log.length) {
        res.write(`event: log\ndata: ${JSON.stringify(job.log.join(''))}\n\n`);
    }
    if (job.status !== 'running') {
        res.write(`event: done\ndata: ${JSON.stringify({ status: job.status, exitCode: job.exitCode })}\n\n`);
        return res.end();
    }

    const listener = (text) => {
        if (text === null) {
            res.write(`event: done\ndata: ${JSON.stringify({ status: job.status, exitCode: job.exitCode })}\n\n`);
            res.end();
        } else {
            res.write(`event: log\ndata: ${JSON.stringify(text)}\n\n`);
        }
    };
    job.listeners.add(listener);
    req.on('close', () => job.listeners.delete(listener));
});

const PORT = process.env.PORT || 8090;
const BIND_ADDR = process.env.BIND_ADDR || '0.0.0.0';

if (require.main === module) {
    app.listen(PORT, BIND_ADDR, () => {
        console.log(`Kiosk Web UI listening on ${BIND_ADDR}:${PORT}`);
    });
}

module.exports = app;