Image Resizer

Sharp powered, multi-threaded image resizing middleware.

Installation

npm install image-resizer-middleware

Usage

import path from 'node:path'
import { fileURLToPath } from 'node:url'
import express from 'express'
import { getMiddleware } from 'image-resizer-middleware'

const __dirname = path.dirname(fileURLToPath(import.meta.url))
const port = 3000
const publicDirectory = path.join(__dirname, 'public')

const app = express()

app.use(getMiddleware({
	basePath: publicDirectory,
	thumbnailsPath: path.join(publicDirectory, 'thumbnails'),
}))
app.use(express.static(publicDirectory))

app.listen(
	port,
	() => console.log(`Listening on http://localhost:${port}`),
)

Every request for an image under basePath which also contains a width, height, max-width or max-height query parameter will be scaled to the specified value.

For example a request for http://localhost:3000/images/test.png?max-width=50&max-height=50 triggers the creation of a proportionally scaled thumbnail with a maximum bounding box of 50px by 50px. It is saved at $(pwd)/public/thumbnails/images/test_50x50>.png and responded to the request.

Algorithm

All images to be scaled are added to a queue. The queue is worked off with one worker per core.