Support for SyncRequestControl #952

const client = ldap.createClient({
  url: bindURL,
});

client.bind(bindDN, bindPassword, (err) => {
  if (err) {
    console.error(err);
    return;
  }
  console.log('bind success');

  client.search(searchDN, {scope: 'base'}, new SyncRequestControl({value: {mode: 3}}), (err, res) => {
    if (err) {
      console.error(err);
      return;
    }

    res.on('searchRequest', ({ messageId, protocolOp, controls }) => {
      console.log(`searchRequest: messageId=${messageId}, protocolOp=${protocolOp}, controls=${controls.map(c => c.type)}`);
    });
    res.on('searchEntry', ({messageID, protocolOp, controls}) => {
      console.log(`entry: messageId=${messageID}, protocolOp=${protocolOp}, controls=${controls.map(c => c.type)}`);
    });
    res.on('searchReference', (referral) => {
      console.log('referral: ' + referral.uris.join());
    });
    res.on('error', (err) => {
      console.error(`error: ${err.name}, ${err.message}, [${err.code}]`);
      client.unbind();
    });
    res.on('end', (result) => {
      console.log('status: ' + result.status);
      client.unbind((err) => {
        if (err) {
          console.error(err);
          return;
        }
        console.log('unbind success');
      });
    });
  });
});

class SyncRequestControl extends Control {
  static OID = '1.3.6.1.4.1.4203.1.9.1.1';

  _value: any;

  constructor(options: any = {}) {
    options.type = SyncRequestControl.OID;
    super(options);

    if (!options.value) {
      return;
    }

    if (typeof options.value === 'object') {
      this._value = options.value;
    } else {
      // TODO check if actually a buffer
      this.parse(options.value);
    }
  }

  get value() {
    return this._value;
  }

  set value(value) {
    this._value = {...value};
  }

  private parse(ber: Buffer) {
    throw new Error('Not implemented');
  }

  _toBer (ber) {
    const writer = new BerWriter();

    writer.startSequence();
    writer.writeInt(this._value.mode, 0x0a);
    writer.endSequence();

    ber.writeBuffer(writer.buffer, 0x04)
    return ber
  }
}