initial import from /x/ monorepo

Signed-off-by: Xe Iaso <me@xeiaso.net>

cmd/anubis/js/main.mjs

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+import { process } from './proof-of-work.mjs';
+import { testVideo } from './video.mjs';
+
+// from Xeact
+const u = (url = "", params = {}) => {
+  let result = new URL(url, window.location.href);
+  Object.entries(params).forEach((kv) => {
+    let [k, v] = kv;
+    result.searchParams.set(k, v);
+  });
+  return result.toString();
+};
+
+const imageURL = (mood) => {
+  return `/.within.website/x/cmd/anubis/static/img/${mood}.webp`;
+};
+
+(async () => {
+  const status = document.getElementById('status');
+  const image = document.getElementById('image');
+  const title = document.getElementById('title');
+  const spinner = document.getElementById('spinner');
+  // const testarea = document.getElementById('testarea');
+
+  // const videoWorks = await testVideo(testarea);
+  // console.log(`videoWorks: ${videoWorks}`);
+
+  // if (!videoWorks) {
+  //   title.innerHTML = "Oh no!";
+  //   status.innerHTML = "Checks failed. Please check your browser's settings and try again.";
+  //   image.src = imageURL("sad");
+  //   spinner.innerHTML = "";
+  //   spinner.style.display = "none";
+  //   return;
+  // }
+
+  status.innerHTML = 'Calculating...';
+
+  const { challenge, difficulty } = await fetch("/.within.website/x/cmd/anubis/api/make-challenge", { method: "POST" })
+    .then(r => {
+      if (!r.ok) {
+        throw new Error("Failed to fetch config");
+      }
+      return r.json();
+    })
+    .catch(err => {
+      title.innerHTML = "Oh no!";
+      status.innerHTML = `Failed to fetch config: ${err.message}`;
+      image.src = imageURL("sad");
+      spinner.innerHTML = "";
+      spinner.style.display = "none";
+      throw err;
+    });
+
+  status.innerHTML = `Calculating...<br/>Difficulty: ${difficulty}`;
+
+  const t0 = Date.now();
+  const { hash, nonce } = await process(challenge, difficulty);
+  const t1 = Date.now();
+
+  title.innerHTML = "Success!";
+  status.innerHTML = `Done! Took ${t1 - t0}ms, ${nonce} iterations`;
+  image.src = imageURL("happy");
+  spinner.innerHTML = "";
+  spinner.style.display = "none";
+
+  setTimeout(() => {
+    const redir = window.location.href;
+    window.location.href = u("/.within.website/x/cmd/anubis/api/pass-challenge", { response: hash, nonce, redir, elapsedTime: t1 - t0 });
+  }, 2000);
+})();

cmd/anubis/js/proof-of-work.mjs

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+// https://dev.to/ratmd/simple-proof-of-work-in-javascript-3kgm
+
+export function process(data, difficulty = 5) {
+  return new Promise((resolve, reject) => {
+    let webWorkerURL = URL.createObjectURL(new Blob([
+      '(', processTask(), ')()'
+    ], { type: 'application/javascript' }));
+
+    let worker = new Worker(webWorkerURL);
+
+    worker.onmessage = (event) => {
+      worker.terminate();
+      resolve(event.data);
+    };
+
+    worker.onerror = (event) => {
+      worker.terminate();
+      reject();
+    };
+
+    worker.postMessage({
+      data,
+      difficulty
+    });
+
+    URL.revokeObjectURL(webWorkerURL);
+  });
+}
+
+function processTask() {
+  return function () {
+    const sha256 = (text) => {
+      const encoded = new TextEncoder().encode(text);
+      return crypto.subtle.digest("SHA-256", encoded.buffer).then((result) =>
+        Array.from(new Uint8Array(result))
+          .map((c) => c.toString(16).padStart(2, "0"))
+          .join(""),
+      );
+    };
+
+    addEventListener('message', async (event) => {
+      let data = event.data.data;
+      let difficulty = event.data.difficulty;
+
+      let hash;
+      let nonce = 0;
+      do {
+        hash = await sha256(data + nonce++);
+      } while (hash.substring(0, difficulty) !== Array(difficulty + 1).join('0'));
+
+      nonce -= 1; // last nonce was post-incremented
+
+      postMessage({
+        hash,
+        data,
+        difficulty,
+        nonce,
+      });
+    });
+  }.toString();
+}
+

cmd/anubis/js/video.mjs

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+const videoElement = `<video id="videotest" width="0" height="0" src="/.within.website/x/cmd/anubis/static/testdata/black.mp4"></video>`;
+
+export const testVideo = async (testarea) => {
+  testarea.innerHTML = videoElement;
+  return (await new Promise((resolve) => {
+    const video = document.getElementById('videotest');
+    video.oncanplay = () => {
+      testarea.style.display = "none";
+      resolve(true);
+    };
+    video.onerror = (ev) => {
+      testarea.style.display = "none";
+      resolve(false);
+    };
+  }));
+};