feat(websub): add hub route (subscribe/unsubscribe)

src/routes/hub.ts

@@ -0,0 +1,80 @@
+import { Hono } from "hono";
+import { Env } from "../types";
+import {
+  verifyAndStoreSubscription,
+  verifyAndDeleteSubscription,
+} from "../utils/websub";
+
+const DEFAULT_LEASE_SECONDS = 86400;
+const MAX_LEASE_SECONDS = 30 * 24 * 3600; // 30 days
+
+export const hubRouter = new Hono();
+
+hubRouter.post("/", async (c) => {
+  const env = c.env as unknown as Env;
+  let form: FormData;
+  try {
+    form = await c.req.formData();
+  } catch {
+    return c.text(
+      "Bad Request: expected application/x-www-form-urlencoded",
+      400,
+    );
+  }
+
+  const mode = form.get("hub.mode");
+  const topic = form.get("hub.topic");
+  const callbackUrl = form.get("hub.callback");
+
+  if (!mode || !topic || !callbackUrl) {
+    return c.text(
+      "Bad Request: hub.mode, hub.topic and hub.callback are required",
+      400,
+    );
+  }
+
+  if (mode !== "subscribe" && mode !== "unsubscribe") {
+    return c.text(
+      "Bad Request: hub.mode must be subscribe or unsubscribe",
+      400,
+    );
+  }
+
+  // Validate that topic matches a known RSS feed on this hub
+  const topicPattern = new RegExp(
+    `^https://${env.DOMAIN.replace(".", "\\.")}/rss/([^/]+)$`,
+  );
+  const match = topic.match(topicPattern);
+  if (!match) {
+    return c.text(
+      "Bad Request: hub.topic must be an RSS feed URL on this hub",
+      400,
+    );
+  }
+  const feedId = match[1];
+
+  const secret = form.get("hub.secret") ?? undefined;
+  const rawLease = parseInt(form.get("hub.lease_seconds") ?? "", 10);
+  const leaseSeconds = isNaN(rawLease)
+    ? DEFAULT_LEASE_SECONDS
+    : Math.min(Math.max(rawLease, 1), MAX_LEASE_SECONDS);
+
+  // Return 202 immediately; verification is async
+  if (mode === "subscribe") {
+    c.executionCtx.waitUntil(
+      verifyAndStoreSubscription(
+        feedId,
+        callbackUrl as string,
+        secret as string | undefined,
+        leaseSeconds,
+        env,
+      ),
+    );
+  } else {
+    c.executionCtx.waitUntil(
+      verifyAndDeleteSubscription(feedId, callbackUrl as string, env),
+    );
+  }
+
+  return c.text("Accepted", 202);
+});