cmd: add Anubis

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

2 files changed, 112 insertions, 0 deletions

diff --git a/cmd/anubis/static/js/main.mjs b/cmd/anubis/static/js/main.mjs
new file mode 100644
index 0000000..d13e1ad
--- /dev/null
+++ b/cmd/anubis/static/js/main.mjs
@@ -0,0 +1,47 @@
+import { process } from './proof-of-work.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();
+};
+
+(async () => {
+  const status = document.getElementById('status');
+  const image = document.getElementById('image');
+  const title = document.getElementById('title');
+
+  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 => {
+      status.innerHTML = `Failed to fetch config: ${err.message}`;
+      image.src = "/.within.website/x/cmd/anubis/static/img/sad.webp";
+      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 = "/.within.website/x/cmd/anubis/static/img/happy.webp";
+
+  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);
+})();
\ No newline at end of file
diff --git a/cmd/anubis/static/js/proof-of-work.mjs b/cmd/anubis/static/js/proof-of-work.mjs
new file mode 100644
index 0000000..4019fec
--- /dev/null
+++ b/cmd/anubis/static/js/proof-of-work.mjs
@@ -0,0 +1,65 @@
+// 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 () {
+    function sha256(text) {
+      return new Promise((resolve, reject) => {
+        let buffer = (new TextEncoder).encode(text);
+
+        crypto.subtle.digest('SHA-256', buffer.buffer).then(result => {
+          resolve(Array.from(new Uint8Array(result)).map(
+            c => c.toString(16).padStart(2, '0')
+          ).join(''));
+        }, reject);
+      });
+    }
+
+    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.substr(0, difficulty) !== Array(difficulty + 1).join('0'));
+
+      nonce -= 1; // last nonce was post-incremented
+
+      postMessage({
+        hash,
+        data,
+        difficulty,
+        nonce,
+      });
+    });
+  }.toString();
+}
+