index.ts

import * as express from 'express'
import * as multer from 'multer'
import * as cors from 'cors'
import * as fs from 'fs'
import * as path from 'path'
import * as Loki from 'lokijs'
import { imageFilter, loadCollection, cleanFolder } from './utils';

// setup
const DB_NAME = 'db.json';
const COLLECTION_NAME = 'images';
const UPLOAD_PATH = 'uploads';
const upload = multer({ dest: `${UPLOAD_PATH}/`, fileFilter: imageFilter });
const db = new Loki(`${UPLOAD_PATH}/${DB_NAME}`, { persistenceMethod: 'fs' });

// optional: clean all data before start
// cleanFolder(UPLOAD_PATH);

// app
const app = express();
app.use(cors());

app.get('/', async (req, res) => {
    // default route
    res.send(`
        <h1>Demo file upload</h1>
        <p>Please refer to <a href="https://scotch.io/tutorials/express-file-uploads-with-multer">my tutorial</a> for details.</p>
        <ul>
            <li>GET /images   - list all upload images</li>
            <li>GET /images/{id} - get one uploaded image</li>
            <li>POST /profile - handle single image upload</li>
            <li>POST /photos/upload - handle multiple images upload</li>
        </ul>
    `);
})

app.post('/profile', upload.single('avatar'), async (req, res) => {
    try {
        const col = await loadCollection(COLLECTION_NAME, db);
        const data = col.insert(req.file);

        db.saveDatabase();
        res.send({ id: data.$loki, fileName: data.filename, originalName: data.originalname });
    } catch (err) {
        res.sendStatus(400);
    }
})

app.post('/photos/upload', upload.array('photos', 12), async (req, res) => {
    try {
        const col = await loadCollection(COLLECTION_NAME, db)
        let data = [].concat(col.insert(req.files));

        db.saveDatabase();
        res.send(data.map(x => ({ id: x.$loki, fileName: x.filename, originalName: x.originalname })));
    } catch (err) {
        res.sendStatus(400);
    }
})

app.get('/images', async (req, res) => {
    try {
        const col = await loadCollection(COLLECTION_NAME, db);
        res.send(col.data);
    } catch (err) {
        res.sendStatus(400);
    }
})

app.get('/images/:id', async (req, res) => {
    try {
        const col = await loadCollection(COLLECTION_NAME, db);
        const result = col.get(req.params.id);

        if (!result) {
            res.sendStatus(404);
            return;
        };

        res.setHeader('Content-Type', result.mimetype);
        fs.createReadStream(path.join(UPLOAD_PATH, result.filename)).pipe(res);
    } catch (err) {
        res.sendStatus(400);
    }
})

app.listen(3000, function () {
    console.log('listening on port 3000!');
})