pad.libre-service.eu-etherpad/src/static/js/admin/settings.js

'use strict';

$(document).ready(() => {
  const loc = document.location;
  const port = loc.port === '' ? (loc.protocol === 'https:' ? 443 : 80) : loc.port;
  const url = `${loc.protocol}//${loc.hostname}:${port}/`;
  const pathComponents = location.pathname.split('/');
  // Strip admin/plugins
  const baseURL = `${pathComponents.slice(0, pathComponents.length - 2).join('/')}/`;
  const resource = `${baseURL.substring(1)}socket.io`;

  // connect
  const room = `${url}settings`;
  const socket = io.connect(room, {path: `${baseURL}socket.io`, resource});

  socket.on('settings', (settings) => {
    /* Check whether the settings.json is authorized to be viewed */
    if (settings.results === 'NOT_ALLOWED') {
      $('.innerwrapper').hide();
      $('.innerwrapper-err').show();
      $('.err-message').html('Settings json is not authorized to be viewed in Admin page!!');
      return;
    }

    /* Check to make sure the JSON is clean before proceeding */
    if (isJSONClean(settings.results)) {
      $('.settings').append(settings.results);
      $('.settings').focus();
      $('.settings').autosize();
    } else {
      alert('YOUR JSON IS BAD AND YOU SHOULD FEEL BAD');
    }
  });

  /* When the admin clicks save Settings check the JSON then send the JSON back to the server */
  $('#saveSettings').on('click', () => {
    const editedSettings = $('.settings').val();
    if (isJSONClean(editedSettings)) {
      // JSON is clean so emit it to the server
      socket.emit('saveSettings', $('.settings').val());
    } else {
      alert('YOUR JSON IS BAD AND YOU SHOULD FEEL BAD');
      $('.settings').focus();
    }
  });

  /* Tell Etherpad Server to restart */
  $('#restartEtherpad').on('click', () => {
    socket.emit('restartServer');
  });

  socket.on('saveprogress', (progress) => {
    $('#response').show();
    $('#response').text(progress);
    $('#response').fadeOut('slow');
  });

  socket.emit('load'); // Load the JSON from the server
});


const isJSONClean = (data) => {
  let cleanSettings = JSON.minify(data);
  // this is a bit naive. In theory some key/value might contain the sequences ',]' or ',}'
  cleanSettings = cleanSettings.replace(',]', ']').replace(',}', '}');
  try {
    return typeof jQuery.parseJSON(cleanSettings) === 'object';
  } catch (e) {
    return false; // the JSON failed to be parsed
  }
};