Method constructor

lib/server.js:217–359

(cfg, listener)

class Server extends EventEmitter {
  constructor(cfg, listener) {
    super();

    if (typeof cfg !== 'object' || cfg === null)
      throw new Error('Missing configuration object');

    const hostKeys = Object.create(null);
    const hostKeyAlgoOrder = [];

    const hostKeys_ = cfg.hostKeys;
    if (!Array.isArray(hostKeys_))
      throw new Error('hostKeys must be an array');

    const cfgAlgos = (
      typeof cfg.algorithms === 'object' && cfg.algorithms !== null
      ? cfg.algorithms
      : {}
    );

    const hostKeyAlgos = generateAlgorithmList(
      cfgAlgos.serverHostKey,
      DEFAULT_SERVER_HOST_KEY,
      SUPPORTED_SERVER_HOST_KEY
    );
    for (let i = 0; i < hostKeys_.length; ++i) {
      let privateKey;
      if (Buffer.isBuffer(hostKeys_[i]) || typeof hostKeys_[i] === 'string')
        privateKey = parseKey(hostKeys_[i]);
      else
        privateKey = parseKey(hostKeys_[i].key, hostKeys_[i].passphrase);

      if (privateKey instanceof Error)
        throw new Error(`Cannot parse privateKey: ${privateKey.message}`);

      if (Array.isArray(privateKey)) {
        // OpenSSH's newer format only stores 1 key for now
        privateKey = privateKey[0];
      }

      if (privateKey.getPrivatePEM() === null)
        throw new Error('privateKey value contains an invalid private key');

      // Discard key if we already found a key of the same type
      if (hostKeyAlgoOrder.includes(privateKey.type))
        continue;

      if (privateKey.type === 'ssh-rsa') {
        // SSH supports multiple signature hashing algorithms for RSA, so we add
        // the algorithms in the desired order
        let sha1Pos = hostKeyAlgos.indexOf('ssh-rsa');
        const sha256Pos = hostKeyAlgos.indexOf('rsa-sha2-256');
        const sha512Pos = hostKeyAlgos.indexOf('rsa-sha2-512');
        if (sha1Pos === -1) {
          // Fall back to giving SHA1 the lowest priority
          sha1Pos = Infinity;
        }
        [sha1Pos, sha256Pos, sha512Pos].sort(compareNumbers).forEach((pos) => {
          if (pos === -1)