LDAP adapter for Keycloak

index.js

const ldap = require('ldapjs');
const fs = require('fs');
const axios = require("axios");
const https = require("https");
const querystring = require('querystring');

const server = ldap.createServer();

const authenticate = async (req, res, next) => {
  if (req.dn.toString() !== 'cn=keycloak' ||
      req.credentials !== 'secret') {
    return next(new ldap.InvalidCredentialsError());
  }

  res.end();
  return next();
};

server.bind('cn=keycloak', authenticate);

const authorize = async (req, res, next) => {
  if (!req.connection.ldap.bindDN.equals('cn=keycloak')) {
    return next(new ldap.InsufficientAccessRightsError());
  }

  return next();
}

const getUsers = async (req, res, next) => {
  const disableSsl = {
    httpsAgent: new https.Agent({
      rejectUnauthorized: false
    })
  }
  const tokenResponse = await axios.post(
    'https://keycloak.localhost/auth/realms/master/protocol/openid-connect/token',
    querystring.stringify({
      client_id: 'admin-cli',
      username: 'admin',
      password: 'password',
      grant_type: 'password'
    }),
    disableSsl
  )
  const token = tokenResponse.data.access_token
  const response = await axios.get(
    'https://keycloak.localhost/auth/admin/realms/applications/users',
    {
      headers: {
        authorization: `Bearer ${token}`
      },
      ...disableSsl
    }
  )
  const users = response.data

  const usersDetails = await Promise.all(users.map(async u => {
    const addr = `https://keycloak.localhost/auth/admin/realms/applications/users/${u.id}/groups`
    const r = await axios
          .get(
            addr,
            {
              headers: {
                authorization: `Bearer ${token}`
              },
              ...disableSsl
            }
          )
    const groups = r.data;

    const {id, username} = u;

    return {
      id,
      username,
      groups
    }
  }));

  req.users = usersDetails;

  return next();
}

const buildData = (u) => ({
  dn: `cn=${u.username},ou=users,o=myhost`,
  attributes: {
    memberOf: [...u.groups.map(({name}) => name), 'Foobar'],
    cn: u.username,
    username: u.username,
    objectClass: 'person'
  }
})

const doFilter = async (req, res, next) => {
  req.users
    .map(buildData)
    .filter(u => req.filter.matches(u.attributes))
    .map(d => {console.log(d); return d;})
    .forEach(d => res.send(d));

  res.end();
  return next();
}

server.search('ou=users', [authorize, getUsers], doFilter)

server.listen(1389, function() {
  console.log('Keycloak LDAP server up at: %s', server.url);
});

package.json

{
  "name": "ldap-keycloak",
  "version": "0.0.1",
  "description": "LDAP adapter for Keycloak",
  "main": "index.js",
  "author": "Ackerley Tng",
  "license": "MIT",
  "dependencies": {
    "axios": "^0.20.0",
    "ldapjs": "^2.2.0"
  }
}