Lean image-resizing service built with Deno + TypeScript. Created for IPFS.

about

Glasgow was built to transform large, high-quality images from an upstream service into fast, digestable smaller ones, on the fly.

We use an in-process cache to avoid needlessly recompressing images and increasing latency. The cache stores the Promise to a result, so two requests in short succession will only hit the upstream service once.

assumptions

The motivation for Glasgow was to run quietly over an IPFS gateway. Accordingly, Glasgow assumes that image paths are immutable, that monty.jpg will only ever resolve to one image. This means that the service will never re-request an image from upstream if it exits in the cache and is only suitable for use cases where the content of a path does not change.

usage

Create config.ts and add your configuration.

export const config: Config = {
	port: 8000,
	upstream: "https://ipfs.prodia.com/ipfs/",
	routes: {
		small: {
			size: 150,
			cache: 50, // maximum cache size in megabytes
		},
		medium: {
			size: 500,
			cache: 50,
		},
		large: {
			size: 1000,
			cache: 50,
		},
	},
};

Run.

deno task start

http://localhost:8000/small/monty.jpg now shows a resized version of http://my-server/my-images/monty.jpg.