uploadio/lib/utils.js

Simple middleware for uploading files.

const fs = require('fs');
const path = require('path');
const { Readable } = require('stream');

// Parameters for safe file name parsing.
const SAFE_FILE_NAME_REGEX = /[^\w-]/g;
const MAX_EXTENSION_LENGTH = 3;

// Parameters to generate unique temporary file names:
const TEMP_COUNTER_MAX = 65536;
const TEMP_PREFIX = 'tmp';
let tempCounter = 0;

/**
 * Builds instance options from arguments objects(can't be arrow function).
 * @returns {Object} - result options.
 */
const buildOptions = function () {
  const result = {};
  [...arguments].forEach((options) => {
    if (!options || typeof options !== 'object') {
      return true;
    }
    Object.keys(options).forEach((i) => (result[i] = options[i]));
  });
  return result;
};

/**
 * Logs message to console if debug option set to true.
 * @param {Object} options - options object.
 * @param {string} msg - message to log.
 * @returns {boolean} - false if debug is off.
 */
const debugLog = (options, msg) => {
  const opts = options || {};
  if (!opts.debug) {
    return false;
  }
  console.log(`File upload: ${msg}`); // eslint-disable-line
  return true;
};

/**
 * Decodes uriEncoded file names.
 * @param fileName {String} - file name to decode.
 * @returns {String}
 */
const uriDecodeFileName = (opts, fileName) => {
  return opts.uriDecodeFileNames ? decodeURIComponent(fileName) : fileName;
};

/**
 * Generates unique temporary file name. e.g. tmp-5000-156788789789.
 * @param {string} prefix - a prefix for generated unique file name.
 * @returns {string}
 */
const getTempFilename = (prefix = TEMP_PREFIX) => {
  tempCounter = tempCounter >= TEMP_COUNTER_MAX ? 1 : tempCounter + 1;
  return `${prefix}-${tempCounter}-${Date.now()}`;
};

const parseFileName = (opts, fileName) => {
  // Check fileName argument
  if (!fileName || typeof fileName !== 'string') {
    return getTempFilename();
  }
  // Cut off file name if it's lenght more then 255.
  const fileLength = 255;
  const parsedName =
    fileName.length <= fileLength ? fileName : fileName.substr(0, fileLength);
  // Decode file name if uriDecodeFileNames option set true.
  return uriDecodeFileName(opts, parsedName);
};

/**
 * Creates a folder for file specified in the path variable
 * @param {Object} fileUploadOptions
 * @param {string} filePath
 * @returns {boolean}
 */
const checkAndMakeDir = (fileUploadOptions, filePath) => {
  // Check upload options were set.
  if (!fileUploadOptions) {
    return false;
  }
  if (!fileUploadOptions.createParentPath) {
    return false;
  }
  // Check whether folder for the file exists.
  if (!filePath) {
    return false;
  }
  const parentPath = path.dirname(filePath);
  // Create folder if it doesn't exist.
  if (!fs.existsSync(parentPath)) {
    fs.mkdirSync(parentPath, {
      recursive: true,
    });
  }
  // Checks folder again and return a results.
  return fs.existsSync(parentPath);
};

/**
 * Builds request fields (using to build req.body and req.files)
 * @param {Object} instance - request object.
 * @param {string} field - field name.
 * @param {any} value - field value.
 * @returns {Object}
 */
const buildFields = (instance, field, value) => {
  // Do nothing if value is not set.
  if (value === null || value === undefined) {
    return instance;
  }
  instance = instance || {};
  // Non-array fields
  if (!instance[field]) {
    instance[field] = value;
    return instance;
  }
  // Array fields
  if (instance[field] instanceof Array) {
    instance[field].push(value);
  } else {
    instance[field] = [instance[field], value];
  }
  return instance;
};

module.exports = {
  buildOptions,
  checkAndMakeDir,
  debugLog,
  parseFileName,
  buildFields,
};