Mastodon metadata proxy using a Cloudflare Worker

README.md

Inspired by this article by Maarten Balliauw, this Cloudflare Worker code enables a proxy for Mastodon metadata under your own domain, with a memorable alias.

This allows people to search for you under your own @user@domain alias, finding your account on whichever server it currently resides on. This has a lot of advantages when it comes to discoverability!

If you move servers, you can update the mastodonHandle value to reflect that; searching for the alias will then direct people to your account on the new server.

Example: search @me@markb.uk on your Mastodon server and you should find my account—if the search isn't currently broken because it's too busy. 😉

worker.js

addEventListener("fetch", (event) => {
    event.respondWith(
        handleRequest(event.request).catch(
            (err) => new Response(err.stack, { status: 500 })
        )
    );
});

async function handleRequest(request) {
    const { pathname, searchParams } = new URL(request.url);

    const path = pathname.trim().replace(/(\/+)$/, '').toLowerCase();

    const notFoundResponse = new Response('Not Found', { status: 404 });

    const mastodonServer = 'https://mastodon.social'
    const mastodonHandle = 'acct:markeebee@mastodon.social';
    const mastodonAlias = 'acct:me@markb.uk';

    if (path == '/.well-known/nodeinfo') {
        return fetch(`${mastodonServer}${path}`);
    }
    
    if (path === '/.well-known/webfinger' || path === '/.well-known/host-meta') {
        // Get the requested resource from the query string
        const requestedResource = searchParams.get('resource');

        // We only want to proxy the specified alias!
        if (requestedResource !== mastodonAlias) {
            return notFoundResponse;
        }

        // Replace the requested alias in the query string with the real resource
        searchParams.set('resource', mastodonHandle);

        // Forward the request on to the real server
        return fetch(`${mastodonServer}${path}?${searchParams}`);
    }

    return notFoundResponse;
}