Rev Fetch

This is a key-based reverse proxy, powered by Cloudflare Workers.

Not working as an any-URL reverse proxy, you can store an URL in the KV, and the code will fetch and return the body for you (URL redirects are followed), like a bridge.

Demo code 
export default {
  /**
   * @param {Request} request
   * @param {Env} env
   * @param {ExecutionContext} ctx
   * @returns {Promise<Response>}
   */
  async fetch(request, { KV }, ctx) {
    if (request.method !== 'GET') {
      return new Response('Method not allowed!', {status: 405});
    }
    // Reading request URL
    const url = new URL(request.url);
    const key = url.pathname.slice(1);
    const val = await KV.get(key);
    if (!val) {
      return new Response("No resource found with this key.", { status: 404 });
    }
    if (isValidHttpUrl(val)) {
      return fetch(url);
    }
    return new Response(`'${val}' is not a valid URL.`, { status: 500 });
  }
}

Fetching Latest GitHub Release

Thing is, we'd also like to fetch GitHub release/workflow assets from time to time.

Use cURL on the browser_download_url is convenient. If it is the latest stable release that you care about, it's even more so to track it with a link like https://github.com/{owner}/{repo}/releases/latest/download/{ASSET_NAME}.

Unfortunately, many projects would add version tag to their release assets, which makes that little trick not so favorable. Sometimes your memory is not working well, and you still need to open the browser and check the URL.

Besides, browser_download_url stucks on private repositories, especially when you want to share an asset with (a limited of) the public.

GitHub provides API access for many things, including dealing with release/workflow assets.

At fisrt, I only thought of workarounds atop of current sturctures. That is, manually querying the release aseets I'd like to share via GitHub API, for their api.github.com URLs. The GitHub auth token is embedded in the URL as its password. The code is modified to specially handle api.github.com/.../assets/ URLs.

Later I found it tiring to manually request the API again and agian. It's also easy to make mistakes finding the URL by my own human hands and eyes. So I think it's time to think of a better way to handle all of this.

First the token should better not be hard-coded, but I'd also like an easy way to reference them rather than passing it directly. It's almost impossible to memorize the token and also inconvient to pass them via -H 'Authorization: Bearer {token}' when using cURL, and it's not easy to customize request headers when using a browser (although I think a decent web UI could do both, memorize the token and customize the header).

So I make it able to query the token from KV, and the token is stored with a name.

Then it should be able to locate the release asset (by name), so I won't need to find what I want (and its URL) on my own. I also make it able to return just the API info, so it's easier to debug and we have a way to check the metadata. This is useful if we are curious about the info itself, or we'd like to see if it's really what we want before requesting the actual asset content.

So, to retrieve an asset from the latest GitHub release, with the asset's name containing the {matcher}.

/gh/latest/{owner}/{repo}/{matcher}

If {matcher} is omitted, release data fetched from the API is returned.

/gh/latest/{owner}/{repo}

Add a info query parameter to get the asset info instead.

/gh/latest/{owner}/{repo}/{matcher}?info

If authorization is needed (e.g., for reading private repos or avoiding rate limits), send the query with the "Authorization" header, or just pass the token via token or auth query parameter.

/gh/latest/{owner}/{repo}?token={TOKEN}
/gh/latest/{owner}/{repo}/{matcher}?token={TOKEN}
/gh/latest/{owner}/{repo}/{matcher}?info&token={TOKEN}

You can also store the token (with a key prefixed with token:, like token:{name}) in KV and pass the {name} via key query parameter.

/gh/latest/{owner}/{repo}?key=name
/gh/latest/{owner}/{repo}/{matcher}?key=name
/gh/latest/{owner}/{repo}/{matcher}?info&key=name

TODO: