Handling File Uploads in Express with Multer

This article provides a comprehensive guide on how to handle file uploads in Express using the Multer middleware. Below is a summary of key points and steps covered:

Key Concepts

1. Multipart Form Data:

   • File uploads use multipart/form-data encoding, which regular body parsers like express.json() cannot handle.

2. Multer Middleware:

   • Parses multipart data from the request.
   • Provides access to uploaded files via req.file or req.files.

3. Storage Configuration:

   • Use multer.diskStorage to define where and how files are stored on disk.
   • Alternatively, use multer.memoryStorage() for in-memory storage.

4. Middleware Functions:

   • upload.single('avatar'): For handling single file uploads.
   • upload.array('photos', 12): For handling multiple file uploads with a limit.
   • upload.fields([ { name: 'avatar', maxCount: 1 }, { name: 'cover', maxCount: 1 } ]): For handling different types of files.

5. Serving Uploaded Files:

   • Use express.static to serve uploaded files from the

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