Using GridFS for storing files into MongoDB

This code sets up an Express server for handling file uploads, downloads, renaming, and deletions using MongoDB's GridFS for storage. Here's a detailed breakdown of what each part of the code does:

1. Imports and Configuration

• express: A web framework for Node.js used to set up the server and define routes.
• bodyParser: Middleware for parsing JSON request bodies.
• logger (morgan): Middleware for logging HTTP requests.
• dotenv: Loads environment variables from a .env file into process.env.
• connectDB: A custom module that handles the connection to the database.
• mongoose: An ODM (Object Data Modeling) library for MongoDB and Node.js, allowing interaction with the MongoDB database.
• upload: A custom utility from ./utils/upload that handles file uploads.
• archiver: A library used for creating ZIP archives.
• stream: Node.js module to handle streaming data.

Configuration and Setup:

• dotenv.config(): Loads environment variables from .env file.
• app = express(): Creates an Express application.
• connectDB(): Establishes a connection to the MongoDB database.

2. GridFS Bucket Initialization

• GridFS: MongoDB specification for storing and retrieving large files like images, audio files, etc.
• bucket: A GridFSBucket instance is created when the MongoDB connection is established. It uses the collection uploads for storing files.

3. Middleware

• bodyParser.json(): Parses incoming requests with JSON payloads.
• logger('dev'): Logs requests to the console.

4. Routes for API Endpoints

• /upload/file:

  • Uploads a single file.
  • Uses upload().single('file') to handle single file uploads.
  • On success, responds with a 201 status and a success message; on failure, responds with a 400 status and an error message.

• /upload/files:

  • Uploads multiple files.
  • Uses upload().array('files') to handle multiple file uploads.
  • Similar success and error handling as the single file upload.

• /download/files/:fileId:

  • Downloads a specific file by its ID.
  • Retrieves the file from GridFS, sets appropriate headers, and pipes the file stream to the response.
  • If the file is not found, responds with a 404 status.

• /download/files-zip:

  • Downloads all files as a ZIP archive.
  • Retrieves all files from GridFS, uses archiver to create a ZIP, and pipes it to the response.
  • If no files are found, responds with a 404 status.

• /download/files-base64:

  • Downloads all files in Base64 format.
  • Retrieves files, converts each file to Base64, and sends an array of Base64 strings in the response.

• /rename/file/:fileId:

  • Renames a file identified by its ID.
  • Uses GridFS's rename function and responds with success or error messages.

• /delete/file/:fileId:

  • Deletes a file by its ID.
  • Uses GridFS's delete function and responds with appropriate success or error messages.

5. Server Listening

• app.listen(port, ...):
  • Starts the server and listens on the specified port (default 3000 if not defined in the environment variables).
  • Logs a message indicating the server is running.

Key Points:

• Error Handling: Each route includes try-catch blocks for handling errors and responding with relevant status codes and messages.
• Streaming: Uses streams extensively for efficient handling of file uploads and downloads.
• Mongoose Integration: Relies on Mongoose for interacting with MongoDB, especially for file management with GridFS.
• Archiver Usage: Utilizes the archiver package to compress files into ZIP format for batch downloads.

This setup provides a comprehensive file management system using Node.js, Express, and MongoDB, facilitating file operations via RESTful API endpoints.

or, Checkout this video demonstration

file-upload-with-mongodb.mp4