Silly CORS

Hate CORS errors? Don't care about security and just want your thing to work? Thanks to this project, you can go silly with CORS!

Silly CORS is a cors-proxy that sits between the browser and request destination. It automatically adds the necessary headers to satisfy browsers' cross-origin requirements.

Note that CORS was not designed to annoy you, but is actually quite useful when properly configured. You shouldn't use CORS proxies in production.

Requirements

This service is designed to be used in Docker behind a reverse proxy. If you don't have one, take a look at traefik, using which will allow you to easily get a minimal setup with SSL certificates.

Architecture: ARM64 or x86_64 (AMD64)

Setup

Use following image with docker run or docker-compose.yml:

ghcr.io/dubzer/silly-cors:latest

Then add Silly CORS to your reverse-proxy config, forwarding to port 3001 (or custom from env variable).

Configuration

Silly CORS uses environment variables for configuration. All of them are optional.

• PORT - by default is 3001.
• SECRET - arbitrary string that can be used for auth. Empty by default (without auth).

API

Everything related to the proxy starts with Silly.

Request headers

• Silly-Secret - if you've configured SECRET env variable, place it's value in this header.

Handling errors

It's important to properly handle any unexpected scenarios.

All errors from Silly CORS will have Silly-Response=true header in them. So you can check for it, and for example, log an error.

Usage example

Let's imagine we've started to get tired from all this sillines and want to reduce its amount by calling HTTP method DELETE on https://api.service.example/cats/1.

To do this, add your destination to the Silly CORS deployment path. In this example, it's https://silly-cors.deployment/. And don't forget about trailing slash or you'll end up with an invalid domain!

After awaiting a promise, we make sure that no errors has occured in Silly CORS by checking the header Silly-Response.

const url = "https://silly-cors.deployment/" + "https://api.service.example/cats/1";
const response = await fetch(url, {
    method: "DELETE", 
});

if (result.headers.get("Silly-Response")) {
    console.error("Oops! Silliness overload", response, await response.text());
    return;
}

return result.json();