TamperMonkey

smart_redirect.js

// ==UserScript==
// @name         Smart Redirector
// @version      1.5
// @description  Redirect specific sites based on a configuration array using smart asterisks.
// @author       Ellis Donovan
// @match        *://*/*
// @run-at       document-start
// @grant        none
// @updateURL    https://gist.githubusercontent.com/EIIisD/80ff22e4959a82bd78ab2ee75adc0d76/raw/smart_redirect.js
// @downloadURL  https://gist.githubusercontent.com/EIIisD/80ff22e4959a82bd78ab2ee75adc0d76/raw/smart_redirect.js
// ==/UserScript==

(function () {
  "use strict";

  /**
   * Configuration: Array of [Match Pattern, Destination URL]
   * - Use * as a wildcard to match any sequence of characters.
   * - Use $1, $2, etc. in the destination to insert the text matched by each * wildcard.
   * - Patterns are matched against the full URL (including protocol).
   * - Matches are case-insensitive.
   * - Trailing slashes are ignored in matching.
   */
  const REDIRECTS = [
    // Kraken
    ["*www.kraken.com/", "https://www.kraken.com/c"],
    ["*www.kraken.com/en-gb", "https://www.kraken.com/c"],

    // Discord
    [
      "*discord.com/",
      "https://discord.com/channels/1405350618880540773/1429704856951586836",
    ],

    // Example using capture groups:
    // ["*://twitter.com/*/status/*", "https://nitter.net/$2/status/$3"],
  ];

  const currentUrl = window.location.href;

  // Normalize URL for comparison (remove trailing slash)
  const normalize = (url) => url.replace(/\/$/, "");

  function getRedirect(url) {
    const cleanUrl = normalize(url);

    for (const [pattern, destination] of REDIRECTS) {
      const cleanPattern = normalize(pattern);

      // Escape regex characters, then replace * with (.*) to capture the wildcard content
      const escapeRegex = (s) =>
        s.replace(/([.*+?^=!:${}()|\[\]\/\\])/g, "\\$1");
      const regexBody = cleanPattern.split("*").map(escapeRegex).join("(.*)");

      // Case-insensitive match against the full string
      const regex = new RegExp("^" + regexBody + "$", "i");

      if (regex.test(cleanUrl)) {
        // Use replace to substitute $1, $2, etc. with captured groups
        return cleanUrl.replace(regex, destination);
      }
    }
    return null;
  }

  // Find matching redirect
  const targetUrl = getRedirect(currentUrl);

  if (targetUrl) {
    // Prevent infinite redirection loop:
    // 1. Exact match
    // 2. Destination is same as current URL but with/without trailing slash
    if (
      currentUrl !== targetUrl &&
      normalize(currentUrl) !== normalize(targetUrl)
    ) {
      console.log(`[Smart Redirector] Redirecting to: ${targetUrl}`);
      window.location.replace(targetUrl);
    }
  }
})();