Jassif Team Institution

CommonJS (Node.js இல் இயல்புநிலை)

const path = require('path');

// Destructure specific methods if needed
const { join, resolve, basename } = require('path');

ES Modules (Node.js 14+ with "type": "module" in package.json)

import path from 'path';

// Or import specific methods
import { join, resolve, basename } from 'path';

const path = require('path');

// Get filename from a path
const filename = path.basename('/users/docs/file.txt');
console.log(filename); // 'file.txt'

// Get filename without extension
const filenameWithoutExt = path.basename('/users/docs/file.txt', '.txt');
console.log(filenameWithoutExt); // 'file'

எடுத்துக்காட்டு: CommonJS இல் __dirname மற்றும் __filename பயன்படுத்துதல்

// CommonJS module (e.g., app.js)
const path = require('path');

// Get the directory name of the current module
console.log('Directory name:', __dirname);

// Get the file name of the current module
console.log('File name:', __filename);

// Building paths relative to the current module
const configPath = path.join(__dirname, 'config', 'app-config.json');
console.log('Config file path:', configPath);

// Getting the directory name using path.dirname()
console.log('Directory using path.dirname():', path.dirname(__filename));

எடுத்துக்காட்டு: ES தொகுதிகளில் __dirname மற்றும் __filename பெறுதல்

// ES Module (e.g., app.mjs or "type": "module" in package.json)
import { fileURLToPath } from 'url';
import { dirname } from 'path';

// Get the current module's URL
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

console.log('ES Module file path:', __filename);
console.log('ES Module directory:', __dirname);

// Example with dynamic imports
async function loadConfig() {
  const configPath = new URL('../config/app-config.json', import.meta.url);
  const config = await import(configPath, { with: { type: 'json' } });
  return config;
}

const path = require('path');

const extension = path.extname('file.txt');
console.log(extension); // '.txt'

console.log(path.extname('index.html')); // '.html'
console.log(path.extname('index.coffee.md')); // '.md'
console.log(path.extname('index.')); // '.'
console.log(path.extname('index')); // ''
console.log(path.extname('.index')); // ''

எடுத்துக்காட்டு: அடிப்படை பாதை இணைத்தல்

const path = require('path');

// Join path segments
const fullPath = path.join('/users', 'docs', 'file.txt');
console.log(fullPath); // Output depends on OS

// Handle relative paths and navigation
console.log(path.join('/users', '../system', './logs', 'file.txt'));

// Handle multiple slashes
console.log(path.join('users', '//docs', 'file.txt')); // Normalizes slashes

எடுத்துக்காட்டு: பாதைகளை தீர்த்தல்

const path = require('path');

// 1. Resolve relative to current working directory
console.log(path.resolve('file.txt'));

// 2. Resolve with multiple segments
console.log(path.resolve('/users', 'docs', 'file.txt'));

// 3. Right-to-left processing
console.log(path.resolve('/first', '/second', 'third')); // '/second/third'

// 4. Using __dirname for module-relative paths
console.log(path.resolve(__dirname, 'config', 'app.json'));

எடுத்துக்காட்டு: கோப்பு பாதையைப் பாகுபடுத்துதல்

const path = require('path');

// Parse a file path
const pathInfo = path.parse('/users/docs/file.txt');
console.log(pathInfo);
/* Output on Unix/macOS:
{
  root: '/',
  dir: '/users/docs',
  base: 'file.txt',
  ext: '.txt',
  name: 'file'
}
*/

// Accessing parsed components
console.log('Directory:', pathInfo.dir); // /users/docs
console.log('Filename:', pathInfo.base); // file.txt
console.log('Name only:', pathInfo.name); // file
console.log('Extension:', pathInfo.ext); // .txt

எடுத்துக்காட்டு: பாதை பொருள்களை வடிவமைத்தல்

const path = require('path');

// Method 1: Using dir and base
const pathString1 = path.format({
  dir: '/users/docs',
  base: 'file.txt'
});
console.log(pathString1); // '/users/docs/file.txt'

// Method 2: Using root, dir, name, and ext
const pathString2 = path.format({
  root: '/',
  dir: '/users/docs',
  name: 'file',
  ext: '.txt'
});
console.log(pathString2); // '/users/docs/file.txt'

// Practical example: Modify and reconstruct a path
const parsedPath = path.parse('/users/docs/old-file.txt');
parsedPath.base = 'new-file.md';
const newPath = path.format(parsedPath);
console.log(newPath); // '/users/docs/new-file.md'

எடுத்துக்காட்டு: பாதைகளை இயல்பாக்குதல்

const path = require('path');

// Resolve relative navigation
console.log(path.normalize('/users/./docs/../data/file.txt')); // '/users/data/file.txt'

// Handle multiple consecutive slashes
console.log(path.normalize('/users//docs////file.txt')); // '/users/docs/file.txt'

// Windows-style paths (automatically handled)
console.log(path.normalize('C:\\users\\docs\\..\\file.txt')); // 'C:\\users\\file.txt'

// Edge cases
console.log(path.normalize('')); // '.'
console.log(path.normalize('.')); // '.'
console.log(path.normalize('..')); // '..'
console.log(path.normalize('/..')); // '/'

எடுத்துக்காட்டு: உறவினர் பாதைகளைக் கண்டறிதல்

const path = require('path');

// Basic relative path
console.log(path.relative('/users/docs/file.txt', '/users/images/photo.jpg'));
// Output: '../../images/photo.jpg'

// Same directory
console.log(path.relative('/users/docs/file1.txt', '/users/docs/file2.txt'));
// Output: 'file2.txt'

// Same file
console.log(path.relative('/users/docs/file.txt', '/users/docs/file.txt'));
// Output: ''

// Different roots (Windows)
console.log(path.relative('C:\\user\\test\\aaa', 'C:\\user\\impl\\bbb'));
// Output: '..\\..\\impl\\bbb'

// Practical example: Creating a relative path for web
const absolutePath = '/var/www/static/images/logo.png';
const webRoot = '/var/www/';
const webPath = path.relative(webRoot, absolutePath).replace(/\\/g, '/');
console.log(webPath); // 'static/images/logo.png'

எடுத்துக்காட்டு: முழுமையான பாதைகளைச் சரிபார்த்தல்

const path = require('path');

// POSIX (Unix/Linux/macOS)
console.log(path.isAbsolute('/users/docs')); // true
console.log(path.isAbsolute('users/docs')); // false

// Windows
console.log(path.isAbsolute('C:\\temp')); // true
console.log(path.isAbsolute('temp')); // false

// UNC paths (Windows network paths)
console.log(path.isAbsolute('\\\\server\\share')); // true

// Practical example: Ensure absolute path for config files
function ensureAbsolute(configPath) {
  return path.isAbsolute(configPath)
    ? configPath
    : path.resolve(process.cwd(), configPath);
}

console.log(ensureAbsolute('config.json')); // Resolves to absolute path
console.log(ensureAbsolute('/etc/app/config.json')); // Already absolute

எடுத்துக்காட்டு: பாதை பிரிப்பான்களுடன் பணிபுரிதல்

const path = require('path');

// Get the platform-specific separator
console.log(`Path separator: ${JSON.stringify(path.sep)}`); // '\\' on Windows, '/' on POSIX

// Building paths safely across platforms
const parts = ['users', 'docs', 'file.txt'];
const filePath = parts.join(path.sep);
console.log('Built path:', filePath);

// Splitting paths correctly
const pathToSplit = process.platform === 'win32'
  ? 'C:\\Users\\docs\\file.txt'
  : '/users/docs/file.txt';
const pathParts = pathToSplit.split(path.sep);
console.log('Split path:', pathParts);

// Normalizing paths with the correct separator
const normalized = path.normalize(`users${path.sep}docs${path.sep}..${path.sep}file.txt`);
console.log('Normalized path:', normalized);

எடுத்துக்காட்டு: PATH சூழல் மாறியுடன் பணிபுரிதல்

const path = require('path');

// Get the platform-specific delimiter
console.log(`Path delimiter: ${JSON.stringify(path.delimiter)}`); // ';' on Windows, ':' on POSIX

// Working with PATH environment variable
function findInPath(executable) {
  if (!process.env.PATH) return null;

  // Split PATH into directories
  const pathDirs = process.env.PATH.split(path.delimiter);

  // Check each directory for the executable
  for (const dir of pathDirs) {
    try {
      const fullPath = path.join(dir, executable);
      require('fs').accessSync(fullPath, require('fs').constants.X_OK);
      return fullPath;
    } catch (err) {
      // File not found or not executable
      continue;
    }
  }
  return null;
}

// Example: Find node executable in PATH
const nodePath = findInPath(process.platform === 'win32' ? 'node.exe' : 'node');
console.log('Node.js path:', nodePath || 'Not found in PATH');

எடுத்துக்காட்டு: எந்த மேடையிலும் விண்டோஸ் பாதைகளுடன் பணிபுரிதல்

const path = require('path');

// Always use Windows-style path handling
const winPath = 'C:\\Users\\user\\Documents\\file.txt';
console.log('Windows basename:', path.win32.basename(winPath));
console.log('Windows dirname:', path.win32.dirname(winPath));

// Normalize Windows paths
console.log('Normalized path:', path.win32.normalize('C:\\\\temp\\\\foo\\..\\bar\\file.txt'));

// Convert between forward and backward slashes
const mixedPath = 'C:/Users/User/Documents//file.txt';
console.log('Normalized mixed slashes:', path.win32.normalize(mixedPath));

// Working with UNC paths
const uncPath = '\\\\server\\share\\folder\\file.txt';
console.log('UNC path components:', path.win32.parse(uncPath));

எடுத்துக்காட்டு: எந்த மேடையிலும் POSIX பாதைகளுடன் பணிபுரிதல்

const path = require('path');

// Always use POSIX-style path handling
const posixPath = '/home/user/documents/file.txt';
console.log('POSIX basename:', path.posix.basename(posixPath));
console.log('POSIX dirname:', path.posix.dirname(posixPath));

// Normalize POSIX paths
console.log('Normalized path:', path.posix.normalize('/usr/local//bin/../lib/file.txt'));

// Working with relative paths
console.log('Relative path:', path.posix.relative('/data/test/aaa', '/data/impl/bbb'));

// Joining paths with POSIX separators
const urlPath = ['static', 'images', 'logo.png'].join(path.posix.sep);
console.log('URL path:', urlPath); // 'static/images/logo.png'

எடுத்துக்காட்டு: தொகுதி பாதை தீர்மானம்

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

// Current module's directory and file info
console.log('Module directory:', __dirname);
console.log('Module file path:', __filename);

// Common path patterns
const paths = {
  // Configuration files relative to project root
  config: path.join(__dirname, '..', 'config', 'app.json'),
 
  // Logs directory (create if doesn't exist)
  logs: path.join(__dirname, '..', 'logs'),
 
  // Public assets
  public: path.join(__dirname, '..', 'public'),
 
  // Uploads directory with proper permissions
  uploads: path.join(__dirname, '..', 'uploads')
};

// Ensure directories exist
async function ensureDirectories() {
  try {
    await Promise.all([
      fs.mkdir(paths.logs, { recursive: true }),
      fs.mkdir(paths.public, { recursive: true }),
      fs.mkdir(paths.uploads, { recursive: true, mode: 0o755 })
    ]);
    console.log('All directories ready');
  } catch (error) {
    console.error('Error creating directories:', error);
  }
}

// Example: Load configuration
async function loadConfig() {
  try {
    const configData = await fs.readFile(paths.config, 'utf8');
    return JSON.parse(configData);
  } catch (error) {
    console.error('Error loading config:', error.message);
    return {};
  }
}

// Example: Log to application log
async function logToFile(message) {
  try {
    const logFile = path.join(paths.logs, `${new Date().toISOString().split('T')[0]}.log`);
    const logMessage = `[${new Date().toISOString()}] ${message}\n`;
    await fs.appendFile(logFile, logMessage, 'utf8');
  } catch (error) {
    console.error('Error writing to log:', error);
  }
}

// Initialize and run examples
(async () => {
  await ensureDirectories();
  const config = await loadConfig();
  console.log('Loaded config:', config);
  await logToFile('Application started');
})();

// ES Module (app.mjs or with "type": "module" in package.json)
import { fileURLToPath } from 'url';
import { dirname, join } from 'path';
import { promises as fs } from 'fs';

// Get current module's directory and file path
const __filename = fileURLToPath(import.meta.url);
const __dirname = dirname(__filename);

// Utility function for path resolution in ES modules
function resolvePath(relativePath) {
  return new URL(relativePath, import.meta.url).pathname;
}

// Example usage
const configPath = join(__dirname, '..', 'config', 'settings.json');
const assetPath = resolvePath('../assets/logo.png');

// Dynamic imports with paths relative to current module
async function loadModule(modulePath) {
  const fullPath = new URL(modulePath, import.meta.url);
  return import(fullPath);
}

எடுத்துக்காட்டு: உற்பத்தி பயன்பாடுகளுக்கான பாதை பயன்பாடுகள்

const path = require('path');
const fs = require('fs/promises');
const os = require('os');

// Path utility class
class PathUtils {
  static get tempDir() {
    return path.join(os.tmpdir(), 'myapp');
  }
 
  static get userHome() {
    return process.env.HOME || process.env.USERPROFILE || os.homedir();
  }

  static async ensureDirectory(dirPath) {
    try {
      await fs.mkdir(dirPath, { recursive: true, mode: 0o755 });
      return true;
    } catch (error) {
      if (error.code !== 'EEXIST') throw error;
      return false;
    }
  }
 
  static isSafePath(baseDir, targetPath) {
    const normalizedBase = path.resolve(baseDir);
    const normalizedTarget = path.resolve(targetPath);
    return normalizedTarget.startsWith(normalizedBase);
  }
 
  static getUniqueFilename(dir, filename) {
    const { name, ext } = path.parse(filename);
    let counter = 1;
    let candidate = filename;
   
    while (fs.existsSync(path.join(dir, candidate))) {
      candidate = `${name} (${counter++})${ext}`;
    }
    return candidate;
  }
}

// Example usage
(async () => {
  // Ensure temp directory exists
  await PathUtils.ensureDirectory(PathUtils.tempDir);
 
  // Safe file operations
  const userUploads = path.join(PathUtils.userHome, 'uploads');
  const safePath = path.join(userUploads, 'profile.jpg');
 
  if (PathUtils.isSafePath(userUploads, safePath)) {
    console.log('Path is safe for operations');
  } else {
    console.error('Potential path traversal attack detected!');
  }
 
  // Generate unique filename
  const uniqueName = PathUtils.getUniqueFilename(
    userUploads,
    'document.pdf'
  );
  console.log('Unique filename:', uniqueName);
 
  // Working with file extensions
  const filePath = '/users/john/docs/report.pdf';
  const fileInfo = {
    name: path.basename(filePath, path.extname(filePath)),
    ext: path.extname(filePath),
    dir: path.dirname(filePath)
  };
  console.log('File info:', fileInfo);
})();

எடுத்துக்காட்டு: பாதுகாப்பான பாதை கையாளுதல்

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

// 1. Prevent directory traversal attacks
function safeJoin(base, ...paths) {
  const targetPath = path.join(base, ...paths);
  const normalizedPath = path.normalize(targetPath);
 
  // Ensure the resulting path is still within the base directory
  if (!normalizedPath.startsWith(path.resolve(base))) {
    throw new Error('Access denied: Path traversal detected');
  }
 
  return normalizedPath;
}

// 2. Validate file extensions
const ALLOWED_EXTENSIONS = new Set(['.jpg', '.jpeg', '.png', '.gif']);

function hasValidExtension(filePath) {
  const ext = path.extname(filePath).toLowerCase();
  return ALLOWED_EXTENSIONS.has(ext);
}

// 3. Safe file operations
async function safeReadFile(baseDir, relativePath) {
  const safePath = safeJoin(baseDir, relativePath);
 
  // Additional security checks
  if (!hasValidExtension(safePath)) {
    throw new Error('Invalid file type');
  }
 
  const stats = await fs.stat(safePath);
  if (!stats.isFile()) {
    throw new Error('Not a file');
  }
 
  return fs.readFile(safePath, 'utf8');
}

// Example usage
(async () => {
  const UPLOAD_DIR = path.join(process.cwd(), 'uploads');
  const userInput = '../../../etc/passwd'; // Malicious input
 
  try {
    // This will throw an error due to path traversal attempt
    const content = await safeReadFile(UPLOAD_DIR, userInput);
    console.log('File content:', content);
  } catch (error) {
    console.error('Security error:', error.message);
  }
})();

எடுத்துக்காட்டு: குறுக்கு-மேடை பாதை கையாளுதல்

const path = require('path');

// Platform detection
const isWindows = process.platform === 'win32';
const isMac = process.platform === 'darwin';
const isLinux = process.platform === 'linux';

// Platform-specific paths
const appDataDir = isWindows
  ? path.join(process.env.APPDATA || path.join(process.env.USERPROFILE, 'AppData', 'Roaming'))
  : path.join(process.env.HOME || process.env.USERPROFILE, isMac ? 'Library/Application Support' : '.config');

// Application-specific directories
const appName = 'MyApp';
const appDir = path.join(appDataDir, appName);

// Ensure application directory exists
require('fs').mkdirSync(appDir, { recursive: true });

// Platform-specific temporary directory
const tempDir = path.join(require('os').tmpdir(), appName);

// Example: Platform-agnostic path handling
function getConfigPath() {
  const configName = 'config.json';

  // Development vs production paths
  if (process.env.NODE_ENV === 'development') {
    return path.join(process.cwd(), 'config', configName);
  }
  
  // Production path
  return path.join(appDir, configName);
}

console.log('Application directory:', appDir);
console.log('Temporary directory:', tempDir);
console.log('Config file path:', getConfigPath());