connection.js

const _ = require("lodash");
const uuid = require("uuid");
const Promise = require("bluebird");
const EventEmitter = require("events");

const BaseConnector = require("./connector/base");
const FileSystem = require("./fs");
const Commands = require("./commands");
const errors = require("./errors");
const DEFAULT_MESSAGE = require("./messages");

class FtpConnection extends EventEmitter {
  constructor(server, options) {
    super();
    this.server = server;
    this.id = uuid.v4();
    this.log = options.log.child({ id: this.id, ip: this.ip });
    this.commands = new Commands(this);
    this.transferType = "binary";
    this.encoding = "utf8";
    this.bufferSize = false;
    this._restByteCount = 0;
    this._secure = false;

    this.connector = new BaseConnector(this);

    this._buffer = "";
    this.commandSocket = options.socket;
    this.commandSocket.on("error", (err) => {
      this.log.error(err, "Client error");
      this.server.emit("client-error", {
        connection: this,
        context: "commandSocket",
        error: err,
      });
    });
    this.commandSocket.on("data", this._handleData.bind(this));
    this.commandSocket.on("timeout", () => {
      this.log.trace("Client timeout");
      this.close();
    });
    this.commandSocket.on("close", () => {
      if (this.connector) this.connector.end();
      if (this.commandSocket && !this.commandSocket.destroyed)
        this.commandSocket.destroy();
      this.removeAllListeners();
    });
  }

  _handleData(data) {
    if (!data.toString(this.encoding).match(/\r\n$/)) {
      this._buffer += data.toString(this.encoding);
      return;
    }
    const messages = _.compact(
      (this._buffer + data.toString(this.encoding)).split("\r\n")
    );
    this._buffer = "";
    this.log.trace(messages);
    return Promise.mapSeries(messages, (message) =>
      this.commands.handle(message)
    );
  }

  get ip() {
    try {
      return this.commandSocket ? this.commandSocket.remoteAddress : undefined;
    } catch (ex) {
      return null;
    }
  }

  get restByteCount() {
    return this._restByteCount > 0 ? this._restByteCount : undefined;
  }
  set restByteCount(rbc) {
    this._restByteCount = rbc;
  }

  get secure() {
    return this.server.isTLS || this._secure;
  }
  set secure(sec) {
    this._secure = sec;
  }

  close(code = 421, message = "Closing connection") {
    return Promise.resolve(code)
      .then((_code) => _code && this.reply(_code, message))
      .finally(() => this.commandSocket && this.commandSocket.destroy());
  }

  login(username, password) {
    return Promise.try(() => {
      const loginListeners = this.server.listeners("login");
      if (!loginListeners || !loginListeners.length) {
        if (!this.server.options.anonymous)
          throw new errors.GeneralError('No "login" listener setup', 500);
      } else {
        return this.server.emitPromise("login", {
          connection: this,
          username,
          password,
        });
      }
    }).then(({ root, cwd, fs, blacklist = [], whitelist = [] } = {}) => {
      this.authenticated = true;
      this.commands.blacklist = _.concat(this.commands.blacklist, blacklist);
      this.commands.whitelist = _.concat(this.commands.whitelist, whitelist);
      this.fs = fs || new FileSystem(this, { root, cwd });
    });
  }

  reply(options = {}, ...letters) {
    const satisfyParameters = () => {
      if (typeof options === "number") options = { code: options }; // allow passing in code as first param
      if (!Array.isArray(letters)) letters = [letters];
      if (!letters.length) letters = [{}];
      return Promise.map(letters, (promise, index) => {
        return Promise.resolve(promise).then((letter) => {
          if (!letter) letter = {};
          else if (typeof letter === "string") letter = { message: letter }; // allow passing in message as first param

          if (!letter.socket)
            letter.socket = options.socket
              ? options.socket
              : this.commandSocket;
          if (!options.useEmptyMessage) {
            if (!letter.message)
              letter.message =
                DEFAULT_MESSAGE[options.code] || "No information";
            if (!letter.encoding) letter.encoding = this.encoding;
          }
          return Promise.resolve(letter.message) // allow passing in a promise as a message
            .then((message) => {
              if (!options.useEmptyMessage) {
                const seperator = !options.hasOwnProperty("eol")
                  ? letters.length - 1 === index
                    ? " "
                    : "-"
                  : options.eol
                  ? " "
                  : "-";
                message = !letter.raw
                  ? _.compact([letter.code || options.code, message]).join(
                      seperator
                    )
                  : message;
                letter.message = message;
              } else {
                letter.message = "";
              }
              return letter;
            });
        });
      });
    };

    const processLetter = (letter) => {
      return new Promise((resolve, reject) => {
        if (letter.socket && letter.socket.writable) {
          this.log.trace(
            {
              port: letter.socket.address().port,
              encoding: letter.encoding,
              message: letter.message,
            },
            "Reply"
          );
          letter.socket.write(
            letter.message + "\r\n",
            letter.encoding,
            (err) => {
              if (err) {
                this.log.error(err);
                return reject(err);
              }
              resolve();
            }
          );
        } else {
          this.log.trace(
            { message: letter.message },
            "Could not write message"
          );
          reject(new errors.SocketError("Socket not writable"));
        }
      });
    };

    return satisfyParameters()
      .then((satisfiedLetters) =>
        Promise.mapSeries(satisfiedLetters, (letter, index) => {
          return processLetter(letter, index);
        })
      )
      .catch((err) => {
        this.log.error(err);
      });
  }
}
module.exports = FtpConnection;