ip_location.ts

// Copyright 2018 The Outline Authors
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file except in compliance with the License.
// You may obtain a copy of the License at
//
//      http://www.apache.org/licenses/LICENSE-2.0
//
// Unless required by applicable law or agreed to in writing, software
// distributed under the License is distributed on an "AS IS" BASIS,
// WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
// See the License for the specific language governing permissions and
// limitations under the License.

import * as maxmind from 'maxmind';

export interface IpLocationService {
  // Returns the 2-digit country code for the IP address.
  countryForIp(ipAddress: string): Promise<string>;
}

// An IpLocationService that uses the node-maxmind package.
// The database is downloaded by scripts/update_mmdb.sh.
// The Dockerfile runs this script on boot and configures the system to run it weekly.
export class MmdbLocationService implements IpLocationService {
  private readonly db: Promise<maxmind.Reader>;

  constructor(filename: string) {
    this.db = new Promise<maxmind.Reader>((fulfill, reject) => {
      // TODO: Change type to maxmind.Options once the type definition is updated
      // with these fields.
      const options: {} = {watchForUpdates: true, watchForUpdatesNonPersistent: true};
      maxmind.open(filename, options, (err, reader) => {
        if (err) {
          reject(err);
        } else {
          fulfill(reader);
        }
      });
    });
  }

  countryForIp(ipAddress) {
    return this.db.then((reader) => {
      if (!reader) {
        throw new Error('MMDB reader is not valid');
      }
      if (!maxmind.validate(ipAddress)) {
        throw new Error('Invalid IP address');
      }
      const result = reader.get(ipAddress);
      return (result && result.country && result.country.iso_code) || 'ZZ';
    });
  }
}