expressjsHow do I store and retrieve a blob using Express.js?

Storing and retrieving a blob using Express.js is a relatively simple process.

First, you need to install the multer package which provides a middleware for handling multipart/form-data, which is necessary for uploading files.

$ npm install --save multer

Once installed, you can create a route in your Express app to handle the file upload.

const multer = require('multer');

const storage = multer.diskStorage({
  destination: (req, file, cb) => {
    cb(null, './uploads');
  },
  filename: (req, file, cb) => {
    cb(null, `${file.fieldname}-${Date.now()}`);
  },
});

const upload = multer({ storage });

app.post('/upload', upload.single('myFile'), (req, res) => {
  // req.file is the `myFile` file
  // req.body will hold the text fields, if there were any
});

To retrieve the blob, you can simply create a route in your Express app that serves the file.

app.get('/uploads/:file', (req, res) => {
  const file = req.params.file;
  const filePath = path.join(__dirname, 'uploads', file);
  res.download(filePath);
});

The parts of the code are:

1. multer package installation - $ npm install --save multer
2. File upload route - creates a route to handle the file upload, using multer and diskStorage
3. File retrieval route - creates a route to serve the file

Helpful links

• Multer
• Express File Uploads

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