Add indications to accounts on Threads for if it is federated with the ActivityPub fediverse.

threads-federation-detector.js

// ==UserScript==
// @name         Threads Federation Detector
// @namespace    http://tampermonkey.net/
// @version      1.0
// @description  Detect federated accounts on Threads. Add indications to accounts on Threads for if it is federated with the ActivityPub fediverse.
// @author       Eana Hufwe
// @match        https://www.threads.com/*
// @match        https://www.threads.net/*
// @match        https://threads.com/*
// @match        https://threads.net/*
// @grant        GM_xmlhttpRequest
// @run-at       document-start
// ==/UserScript==

(function() {
    'use strict';

    // Cache for webfinger results
    const federationCache = new Map();
    const visitedLinks = new WeakSet();

    // Add CSS for the federation indicator
    const style = document.createElement('style');
    style.textContent = `
        a.federation-indicator.federated {
            filter: drop-shadow(0 0 3px #00d084) drop-shadow(0 0 6px #00d084);
        }

        a.federation-indicator:not(.federated) {
            filter: drop-shadow(0 0 3px #ff3b30) drop-shadow(0 0 6px #ff3b30);
            text-decoration: line-through;
        }
    `;
    document.head.appendChild(style);

    function checkWebfinger(account) {
        return new Promise((resolve) => {
            GM_xmlhttpRequest({
                method: 'GET',
                url: `https://threads.net/.well-known/webfinger?resource=acct:${account}@threads.net`,
                onload: function(response) {
                    resolve(response.status === 200);
                },
                onerror: function() {
                    resolve(false);
                }
            });
        });
    }

    async function processAccountLink(link) {
        if (link.classList.contains('federation-indicator')) {
            return;
        }

        const href = link.getAttribute('href');
        const match = href.match(/^\/@([a-zA-Z0-9_\-\.]+)$/);

        if (!match) {
            return;
        }

        const account = match[1];

        // Check cache first
        if (federationCache.has(account)) {
            if (federationCache.get(account)) {
                addFederationIndicator(link);
            } else {
                addNonFederationIndicator(link);
            }
            return;
        }

        // Make webfinger request
        const isFederated = await checkWebfinger(account);
        console.log("checkWebfinger", account, isFederated);
        federationCache.set(account, isFederated);

        if (isFederated) {
            addFederationIndicator(link);
        } else {
            addNonFederationIndicator(link);
        }
    }

    function addFederationIndicator(link) {
        // Check if indicator already exists
        if (link.classList.contains('federation-indicator')) {
            return;
        }

        link.classList.add('federation-indicator', 'federated');
        link.title = 'Federated account';
    }

    function addNonFederationIndicator(link) {
        // Check if indicator already exists
        if (link.classList.contains('federation-indicator')) {
            return;
        }

        link.classList.add('federation-indicator');
        link.title = 'Non-federated account';
    }

    function scanForAccountLinks() {
        const links = document.querySelectorAll('a[href^="/@"]');
        links.forEach(processAccountLink);
    }

    // Initial scan when DOM is ready
    if (document.readyState === 'loading') {
        document.addEventListener('DOMContentLoaded', scanForAccountLinks);
    } else {
        scanForAccountLinks();
    }

    // Watch for dynamic content changes
    const observer = new MutationObserver((mutations) => {
        let hasNewLinks = false;
        mutations.forEach((mutation) => {
            mutation.addedNodes.forEach((node) => {
                if (node.nodeType === Node.ELEMENT_NODE) {
                    const shouldLog = node?.innerHtml?.match(/href="@\/[a-zA-Z0-9_\-\.]+"/g);
                    if (node.matches('a[href^="/@"]')) {
                        if (shouldLog) console.log("added node match", node);
                        processAccountLink(node);
                        hasNewLinks = true;
                    } else if (node.querySelector) {
                        const newLinks = node.querySelectorAll('a[href^="/@"]');
                        if (shouldLog) console.log("added node qs", node, newLinks);
                        if (newLinks.length > 0) {
                            newLinks.forEach(processAccountLink);
                            hasNewLinks = true;
                        }
                    } else {
                        if (shouldLog) console.log("added node else", node);
                    }
                }
            });
        });
    });

    observer.observe(document.body || document.documentElement, {
        childList: true,
        subtree: true
    });
})();