quad-image

A very, very simple image hosting API, plus support files.

• You send it an image.
• The image is decoded and re-encoded using Piston Image.
• The image is saved to the local disc.
• The URL of the image is returned.

Building

quad-image probably only works on libc/Unix operating systems. It requires Rust, stable should be fine.

Build it by running cargo build --release, and grabbing the binary from target/release/quad-image.

Hosting

The expected deployment situation is:

• quad-image running under a service manager.
• the web/ subdirectory being served by a webserver
• the webserver proxying traffic to quad-image.

There are example config files in quad-image.nginx (for nginx) and quad-image.service (for systemd). All the ports/addresses are hardcoded.

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A Dockerfile is provided, if you prefer that kind of thing. It performs an isolated build and provides a minimal alpine-based container. It is not CI'd or published.

You could run it like this, if you trusted Docker's to manage your data storage, which I wouldn't recommend:

docker run --name quad-image -p 6600:80 -it $(docker build -q .)

Safety

HTTP is handled by Rouille, a simple Rust HTTP library. It's expected that you will run the API server behind nginx, so it doesn't even have to cope with TLS or any HTTP weirdness.

Users have no control over the target filename. They cannot plausibly overwrite files on the server, or generate URLs of their choosing.

Images are decoded and re-encoded using Piston Image before writing to the filesystem, there should be no way to get non-image data served. That is, all files that make it to the filesystem are valid, minimal images with no extra information in, either in metadata or elsewhere in the file.

This protects against:

• users uploading images with their GPS location in metadata
• serving exploits for other image libraries
• distributing payloads that aren't part of the image
• misconfigured webservers attempting to execute uploaded files as PHP

Piston Image is a Rusty library which probably doesn't have all the memory corruption bugs that libpng, libjpeg, etc. have, and almost certainly doesn't have all the insane failure modes that imagemagick's convert has.