multiverproxy

A Cloudflare Worker designed to proxy Lunar Client's multiver changes.

• demo the proxy

Important Notice:
This worker is currently under development, and its reliability has not been fully tested.
It is not recommended for use in projects until this notice is removed.

How the Worker Works

Constants

const PROXY = 'multiverproxy.unethical.team';
const YML_URL = 'https://launcherupdates.lunarclientcdn.com/latest.yml';

• PROXY: This sets the expected hostname for incoming requests. If a request's 'host' header doesn't match this value, the worker responds with an 'Access Denied' message. It's specific to our use case and not required.
• YML_URL: This stores the URL of Lunar Client's 'latest.yml' file, which contains info about the latest Lunar Client launcher version.

Event Listener

addEventListener('fetch', (event) => {
  event.respondWith(handleRequest(event.request));
});

• This listener triggers whenever a fetch request is made to the worker. It calls the handleRequest function to process the request and respond accordingly.

fetchLatestLauncherVersion

async function fetchLatestLauncherVersion() {
  if (ymlContent) return latestVersion;

  try {
    const response = await fetch(YML_URL);
    if (response.ok) {
      ymlContent = await response.text();
      const match = ymlContent.match(/version: (.+)/);
      latestVersion = match && match[1] ? match[1] : '1.0.0';
    } else {
      throw new Error(`Failed to fetch YML content: ${response.status} ${response.statusText}`);
    }
    return latestVersion;
  } catch (error) {
    throw new Error(`Failed to fetch latest launcher version: ${error.message}`);
  }
}

• This fetches the latest version of the Lunar Client's launcher from the 'latest.yml' file. This information is used in handleRequest.

handleRequest

async function handleRequest(request) {
  try {
    if (request.headers.get('host') !== PROXY) {
      return new Response('Access Denied.', {
        status: 403,
      });
    }

    const launcherVersion = await fetchLatestLauncherVersion();
    const targetURL = 'https://api.lunarclientprod.com/launcher/launch';

    const headers = {
      'Content-Type': 'application/json; charset=UTF-8',
      'User-Agent': `Lunar Client Launcher v${launcherVersion}`,
    };

    const response = await fetch(targetURL, {
      method: 'POST',
      headers: headers,
      body: JSON.stringify({
        version: '1.8.9',
        branch: 'master',
        os: 'win32',
        arch: 'x64',
        launcher_version: launcherVersion,
        hwid: '0',
      }),
    });

    if (!response.ok) {
      throw new Error(`Request to Lunar Client API failed with status ${response.status}`);
    }

    return response;
  } catch (error) {
    console.error('Error in handleRequest:', error);
    return new Response('An error occurred while processing the request.', { status: 500 });
  }
}

• This function manages incoming requests and acts as a proxy for Lunar Client's API.
• It checks if the 'host' header in the incoming request matches the expected 'PROXY' constant. If not, it responds with a '403 Access Denied' error.
• It then calls fetchLatestLauncherVersion to obtain the latest launcher version.
• It sends a POST request to the Lunar Client API.
• If the request succeeds, it returns the response from the Lunar Client API.
• If the request fails, it responds with a '500 Internal Server Error' and logs the error for debugging purposes.