plainpicture / node-zipper

A tiny nodejs app to generate and stream zipfiles

Zipper

Zipper is a tiny nodejs app, which takes a URL pointing to a json file that lists files (URLs) you want to generate a zipfile for while streaming it to your client.

Use case

Say, you want to provide your users a way to download a number of files, e.g. large images or arbitrary blobs. You can implement this by generating a zipfile in background workers, upload it to e.g. S3 and point the user to this uploaded file. However, if the zip is comprised of many large files, your workers will be blocked for a long time and the user has to wait for the actual upload before he/she can start downloading the file. Streaming the zipfile from within your frontend is probably not possible as well, due to timeouts, memory issues, missing streaming support, etc. Using zipper, you can offload the zip file generation and streaming from your app, by a) uploading a multiline json file to e.g. http://url.to/file.json:

{ filename: "filename1.jpg", url: "http://url.to/filename1.jpg" }
{ filename: "filename2.jpg", url: "http://url.to/filename2.jpg" }
...

and b) redirecting the user to zipper while pointing to the uploaded file:

http://zipper.host:8080/generate?signature=SIGNATURE&url=http://url.to/file.json&filename=file.zip

Zipper will then download the file, download the listed files one after another while generating a zip file and stream it to the user as file.zip.

Installation

$ npm install
$ PORT=8080 BIND=0.0.0.0 TOKEN=SECRET_TOKEN node app.js

Signature

The signature is build and checked via sha256(token + ":" filename + ":" + url)