Create and link DB users for social logins

wp-special-link-rule.js

function (user, context, callback) {
  /* Disclaimer: Not well-tested. Might have clashes with existing linking rules, enterprise connections, etc */
  console.log('-- User creation/linking rule --');
  
  var DB_CONN = 'DB_CONNECTION_NAME_HERE';
  
  if (context.clientID !== 'CLIENT_ID_HERE') {
    return callback(null, user, context);
  }
  
  var dbIdentity = _.find(user.identities, { connection: DB_CONN });
  if (dbIdentity) {
    console.log('User already has a database account');
    return callback(null, user, context);
  }
  
  console.log('User has no DB identity. Going to create one.');
  
  /* Obtain Management API token */
  request.post({
    url: 'https://' + auth0.domain + '/oauth/token',
    json: { 'client_id': configuration.API_EXPLORER_CLIENT_ID, 'client_secret': configuration.API_EXPLORER_CLIENT_SECRET, 'audience':auth0.baseUrl+'/', 'grant_type':'client_credentials'}
  }, function(err, response, body) {
    if (err || response.statusCode >= 400) {
      console.log('Error obtaining access token.', err ? err : response.statusMessage);
      return callback(err);
    }
    
    var token = body.access_token;
    console.log('Obtained access token.', token);
    /* Create DB user */
    request.post({
      url: auth0.baseUrl + '/users',
      headers: {
        Authorization: 'Bearer ' + token
      },
      json: {
        connection: DB_CONN,
        email: user.email,
        username: user.email.split('@')[0],
        password: require('uuid').v4()
      }
    }, function(err2, response2, body2) {
      if (err2 || response2.statusCode >= 400) {
        console.log('Error creating user.', err2 ? err2 : response2.statusMessage);
        return callback(err2);
      }
      
      console.log('Created new user', body2);
      var dbUserId = body2.identities[0].user_id;
      
      /* Link DB user to current user */
      request.post({
        url: auth0.baseUrl + '/users/' + user.user_id + '/identities',
        headers: {
          Authorization: 'Bearer ' + token
        },
        json: { provider: 'auth0', user_id: dbUserId }
      }, function(err3, response3, body3) {
        if (err3 || response3.statusCode >= 400) {
          console.log('Error linking user.', err3 ? err3 : response3.statusMessage);
          return callback(err3);
        }
        
        console.log('DB user successfully created and linked');
        return callback(null, user, context);
      }); // link user
    }); // create user
  }); // /oauth/token
  
}