Soliditas

A matrix media proxy as cloudflare worker.

Environment variables

• HOSTNAME: the hostname, for example example.org
• SERVERNAME: the servername, for example example.org
• KLIPY_API_KEY (optional secret): previews Klipy links through the Klipy API

Constructing media id

Example in TypeScript, as seen in mxcId.ts:

function toBase64Url(value: string): string {
  const bytes = new TextEncoder().encode(value);
  let binary = '';

  for (const byte of bytes) {
    binary += String.fromCodePoint(byte);
  }

  return btoa(binary).replaceAll('+', '-').replaceAll('/', '_').replaceAll(/=+$/g, '');
}

function toMatrixID(fname: string, prefix: string): string {
  const base64 = toBase64Url(fname);
  return prefix + base64;
}

You can test it against the /_soliditas/adressconvert?remoteType=[remoteType]&remoteId=[remoteID] endpoint.

Supported proxied upstreams

Giphy

You need to generate a matrix id, using the algorithm as shown above.

Example:

1. The giphy id is yXPquATCb8kGk, this has been translated using the toMatrixID function, see above, to giphy_XPquATCb8kGk.
2. mxc: mxc://example.org/giphy_XPquATCb8kGk
3. will return a redirect to https://i.giphy.com/yXPquATCb8kGk.webp

Tenor

You need to generate a matrix id, using the algorithm as shown above.

Example:

To-Do

Klipy

You need to generate a matrix id, using the algorithm as shown above.

Example:

1. The path on the klipy cdn is ffd4ac143e6335ac68951b787d3c1902/e8/3a/5LM0jRpL.gif
2. mxc: mxc://example.org/klipy_ZmZkNGFjMTQzZTYzMzVhYzY4OTUxYjc4N2QzYzE5MDIvZTgvM2EvNUxNMGpScEwuZ2lm
3. will return a redirect to https://static.klipy.com/ii/ffd4ac143e6335ac68951b787d3c1902/e8/3a/5LM0jRpL.gif

Link previews

GET /_soliditas/preview_url?url=[url] answers in the shape of the Matrix /preview_url endpoint. Missing og: tags are filled from twitter: tags, <title>, <meta name="description"> and oEmbed. Twitter/X links are read from the FxTwitter API, Bluesky posts from their author's PDS, Reddit and TikTok titles from their oEmbed endpoints, Klipy GIFs, stickers and clips from the Klipy API, Tumblr posts without an image get the fxtumblr render, and fediverse posts are read from their ActivityPub object.

The scraper is the Rust crate sable-link-preview, which the Sable client also runs natively. wasm/ compiles it for the worker, and pnpm build:wasm (run before test, dev and deploy) needs Rust with the wasm32-unknown-unknown target and wasm-bindgen-cli 0.2.130.

Posts from X, Bluesky, the fediverse, Tumblr, Reddit and TikTok, and pages that declare og:type note, are answered with og:type note and Sable's note: Open Graph keys: the author, text, counts, content warning, every image and video (og:image, then og:image:1, og:image:2...) and the quoted post under related:1:, described in the sable-link-preview README.

og:image is returned as mxc://[servername]/og_[base64url of the image url]. When a page has more than one image, com.sable.images lists up to ten of them as { url, width, height }, and og:image stays the single image other clients show.

License

This project is licensed under Apache 2.0, see LICENSE.