Update samba shares as drives are mounted / unmounted on an RPi

media-watch.js

import { readdirSync, watch, readFileSync, writeFileSync } from 'fs';
import { exec } from 'child_process';

const PATHNAME = '/media/pi';
const SMB_CONF = '/etc/samba/smb.conf';

let currentMedia = [];

function getMedia() {
    return readdirSync(PATHNAME);
}

function readSmbConf() {
    return readFileSync(SMB_CONF).toString();
}

function updateSmbConf(shares) {
    const conf = readSmbConf();

    const entryString = '###### auto shares setup';
    const regexp = new RegExp(`${entryString}.*`, 's');

    const updated = conf.replace(regexp, `${entryString}\n${shares.map(share => buildShare(share)).join('\n')}`)

    writeFileSync(SMB_CONF, updated);

    restartSmb()
}

function restartSmb() {
    exec('sudo systemctl restart smbd');
}

function buildShare(share) {
    return `
[${share}]
   comment = ${share} Mounted Media
   path = ${PATHNAME}/${share}
   browseable = yes
   read only = yes
   guest ok = no
   force user = pi
`
}

watch(PATHNAME, (eventType, filename) => {
    const updated = getMedia()

    if(updated.length !== currentMedia.length) {
        updateSmbConf(updated)
        console.log('Updating shares')
    } else {
        console.log('Skipping shares update')
    }

    currentMedia = updated;
});

currentMedia = getMedia()
updateSmbConf(currentMedia);
console.log('Shares initialized')