Multer Example

multer_example.js

const express = require('express');
const multer = require('multer');
const { v4: uuidv4 } = require('uuid');
const fs = require('fs');
const path = require('path');
const Resource = require('./models/Resource'); // Assuming you have a Resource model defined

const app = express();

// Set up multer storage configuration
const storage = multer.diskStorage({
  destination: function (req, file, cb) {
    cb(null, 'uploads/');
  },
  filename: function (req, file, cb) {
    const filename = uuidv4() + path.extname(file.originalname);
    cb(null, filename);
  }
});

const upload = multer({
  storage: storage,
  limits: { fileSize: 5 * 1024 * 1024 } // 5MB file size limit
}).single('pdfFile');

// Endpoint to handle file upload
app.post('/upload', (req, res) => {
  upload(req, res, async function (err) {
    if (err instanceof multer.MulterError) {
      // A multer error occurred (e.g., file size exceeded limit)
      return res.status(400).json({ error: 'File size exceeded limit' });
    } else if (err) {
      // An unknown error occurred
      return res.status(500).json({ error: 'Unknown error occurred' });
    }

    // Check if file is not provided
    if (!req.file) {
      return res.status(400).json({ error: 'No file provided' });
    }

    // Check if file is not a PDF
    if (req.file.mimetype !== 'application/pdf') {
      // Delete uploaded file
      fs.unlinkSync(req.file.path);
      return res.status(400).json({ error: 'File must be a PDF' });
    }

    // Save file information to database
    const resource = new Resource({
      originalName: req.file.originalname,
      filename: req.file.filename,
      size: req.file.size,
      uploadedAt: new Date(),
      creator: req.user // Assuming you have user authentication and req.user contains user info
    });

    try {
      await resource.save();
      res.status(200).json({ message: 'File uploaded successfully' });
    } catch (error) {
      // If an error occurred while saving to the database
      // Delete uploaded file
      fs.unlinkSync(req.file.path);
      res.status(500).json({ error: 'Failed to save file information to database' });
    }
  });
});

app.listen(3000, () => {
  console.log('Server is running on port 3000');
});