This code defines a module that reads session data from a JSON file at SESSIONS_PATH and returns an array of session data. It also includes error handling to reset the session array if an error occurs while reading the file.

Cell 10

var fs = require('fs');
var path = require('path');

var TOKEN_DIR = path.join(process.env.HOME || process.env.HOMEPATH || process.env.USERPROFILE, '.credentials');
var SESSIONS_PATH = path.join(TOKEN_DIR, 'sessions.json');

var sessions = [];
var sessionModified = 0;

function readSessions() {
    try {
        if(fs.existsSync(SESSIONS_PATH)
           && fs.statSync(SESSIONS_PATH).mtime.getTime() > sessionModified) {
            sessionModified = fs.statSync(SESSIONS_PATH).mtime.getTime();
            sessions = JSON.parse(fs.readFileSync(SESSIONS_PATH)
                .toString());
        }
    } catch (e) {
        sessions = [];
    }
    return sessions;
};
module.exports = readSessions;

const fs = require('fs').promises;
const path = require('path');

const TOKEN_DIR = path.join(
  process.env.HOME || process.env.HOMEPATH || process.env.USERPROFILE,
  '.credentials'
);
const SESSIONS_PATH = path.join(TOKEN_DIR,'sessions.json');

let sessions = [];
let sessionModified = 0;

/**
 * Reads sessions from the JSON file at SESSIONS_PATH.
 * If the file is newer than the last modification, it is updated.
 * @returns {Promise} An array of session objects.
 */
async function readSessions() {
  try {
    // Check if the sessions file exists and is newer than the last modification
    if (await fs.access(SESSIONS_PATH)) {
      const stats = await fs.stat(SESSIONS_PATH);
      if (stats.mtimeMs > sessionModified) {
        // Update sessionModified and sessions
        sessionModified = stats.mtimeMs;
        sessions = JSON.parse(await fs.readFile(SESSIONS_PATH, 'utf8'));
      }
    }
  } catch (e) {
    // If an error occurs, reset sessions to an empty array
    sessions = [];
  }
  return sessions;
}

module.exports = readSessions;

Code Breakdown

Module Dependencies

• fs: File system module for interacting with the file system.
• path: Module for working with file paths.

Constants

• TOKEN_DIR: Directory path for storing credentials, constructed from the following environment variables in order of preference:
  • HOME
  • HOMEPATH
  • USERPROFILE
• SESSIONS_PATH: Path to the'sessions.json' file within TOKEN_DIR.

Variables

• sessions: Array to store session data.
• sessionModified: Timestamp of the last modification to the'sessions.json' file.

Function: readSessions()

1. Checks if the'sessions.json' file exists and has been modified since the last read.
2. If the file exists and has been modified, reads its contents, parses it as JSON, and updates the sessions array.
3. Returns the sessions array.

Error Handling

• If an error occurs while reading the file, the sessions array is reset to an empty array.

Export

• The readSessions function is exported as a module.