fix(docs-site): stop doubling the /ktx basePath on alias-host redirects (#263)

ktx.sh/ and docs.ktx.sh/ redirected to
https://docs.kaelio.com/ktx/ktx/docs/... (note the doubled /ktx) and 404'd.

The host-agnostic `source: "/"` redirect ran before the alias-host
canonicalizers, so it injected the /ktx basePath into the path on the alias
domains, which the alias catch-all then prepended a second time.

Reorder redirects() so alias-host canonicalization runs first, leaving the
generic root/docs rules for the local/canonical host only. The /stars
exclusion stays because redirects run before beforeFiles rewrites.

Add Host-spoofing regression tests (the prior tests only used localhost,
which never exercised the alias-host rules) and remove the vestigial
website/vercel.json, which the live ktx.sh routing already bypasses.

Co-authored-by: Claude Opus 4.8 <noreply@anthropic.com>

docs-site/next.config.mjs

@@ -30,7 +30,36 @@ const config = {
     };
   },
   async redirects() {
+    // Alias-host canonicalization MUST come before the generic root/docs
+    // redirects below. Those generic rules have no host guard, so if they ran
+    // first they would inject a "/ktx" basePath into the path on the alias
+    // hosts, which the alias catch-alls would then prepend a second time —
+    // producing https://docs.kaelio.com/ktx/ktx/docs/... Redirects also run
+    // before beforeFiles rewrites, so the ktx.sh catch-all must exclude
+    // /stars* to let the stars dashboard rewrite proxy through.
     return [
+      {
+        source: "/slack",
+        has: [{ type: "host", value: "ktx.sh" }],
+        destination:
+          "https://join.slack.com/t/ktxcommunity/shared_invite/zt-3y9b44m1x-LVyNNJD5nwaZHq4XS29LMQ",
+        permanent: false,
+        basePath: false,
+      },
+      {
+        source: "/:path*",
+        has: [{ type: "host", value: "docs.ktx.sh" }],
+        destination: "https://docs.kaelio.com/ktx/:path*",
+        permanent: true,
+        basePath: false,
+      },
+      {
+        source: "/:path((?!stars(?:/|$)).*)",
+        has: [{ type: "host", value: "ktx.sh" }],
+        destination: "https://docs.kaelio.com/ktx/:path",
+        permanent: true,
+        basePath: false,
+      },
       {
         source: "/",
         destination: "/ktx/docs/getting-started/introduction",
@@ -43,28 +72,6 @@ const config = {
         permanent: false,
         basePath: false,
       },
-      {
-        source: "/:path*",
-        has: [{ type: "host", value: "docs.ktx.sh" }],
-        destination: "https://docs.kaelio.com/ktx/:path*",
-        permanent: true,
-        basePath: false,
-      },
-      {
-        source: "/slack",
-        has: [{ type: "host", value: "ktx.sh" }],
-        destination:
-          "https://join.slack.com/t/ktxcommunity/shared_invite/zt-3y9b44m1x-LVyNNJD5nwaZHq4XS29LMQ",
-        permanent: false,
-        basePath: false,
-      },
-      {
-        source: "/:path((?!stars(?:/|$)).*)",
-        has: [{ type: "host", value: "ktx.sh" }],
-        destination: "https://docs.kaelio.com/ktx/:path",
-        permanent: true,
-        basePath: false,
-      },
     ];
   },
 };

docs-site/tests/docs-index-route.test.mjs

@@ -2,6 +2,8 @@ import assert from "node:assert/strict";
 import { spawn } from "node:child_process";
 import { once } from "node:events";
 import { readFile, writeFile } from "node:fs/promises";
+import http from "node:http";
+import https from "node:https";
 import { dirname, join } from "node:path";
 import { createServer } from "node:net";
 import { after, before, test } from "node:test";
@@ -100,6 +102,37 @@ after(async () => {
   }
 });
 
+// Node's fetch (undici) overwrites the Host header with the connection host,
+// so the alias-host redirect rules never match. The low-level http(s) client
+// sends Host verbatim, which is what the alias canonicalization keys off of.
+function requestWithHost(hostHeader, path) {
+  const target = new URL(docsSiteUrl);
+  const client = target.protocol === "https:" ? https : http;
+  const port =
+    target.port || (target.protocol === "https:" ? "443" : "80");
+
+  return new Promise((resolve, reject) => {
+    const request = client.request(
+      {
+        hostname: target.hostname,
+        port,
+        path,
+        method: "GET",
+        headers: { Host: hostHeader },
+      },
+      (response) => {
+        response.resume();
+        resolve({
+          status: response.statusCode,
+          location: response.headers.location,
+        });
+      },
+    );
+    request.on("error", reject);
+    request.end();
+  });
+}
+
 test("/ktx/docs redirects to the docs introduction", async () => {
   const response = await fetch(`${docsSiteUrl}${docsBasePath}/docs`, {
     redirect: "manual",
@@ -141,3 +174,51 @@ test("/ktx/api/search returns docs search results", async () => {
     "search should return at least one docs result",
   );
 });
+
+test("ktx.sh canonicalizes to a single /ktx basePath on the docs host", async () => {
+  const root = await requestWithHost("ktx.sh", "/");
+  assert.equal(root.status, 308);
+  assert.equal(root.location, "https://docs.kaelio.com/ktx/");
+  assert.ok(
+    !root.location.includes("/ktx/ktx"),
+    "the basePath must not be doubled",
+  );
+
+  const page = await requestWithHost(
+    "ktx.sh",
+    "/docs/getting-started/quickstart",
+  );
+  assert.equal(page.status, 308);
+  assert.equal(
+    page.location,
+    "https://docs.kaelio.com/ktx/docs/getting-started/quickstart",
+  );
+});
+
+test("docs.ktx.sh canonicalizes to a single /ktx basePath on the docs host", async () => {
+  const root = await requestWithHost("docs.ktx.sh", "/");
+  assert.equal(root.status, 308);
+  assert.equal(root.location, "https://docs.kaelio.com/ktx");
+  assert.ok(
+    !root.location.includes("/ktx/ktx"),
+    "the basePath must not be doubled",
+  );
+
+  const page = await requestWithHost("docs.ktx.sh", "/llms.txt");
+  assert.equal(page.status, 308);
+  assert.equal(page.location, "https://docs.kaelio.com/ktx/llms.txt");
+});
+
+test("ktx.sh keeps the /slack and /stars exceptions", async () => {
+  const slack = await requestWithHost("ktx.sh", "/slack");
+  assert.equal(slack.status, 307);
+  assert.match(slack.location, /^https:\/\/join\.slack\.com\//);
+
+  // /stars is proxied by a beforeFiles rewrite, so the apex catch-all must not
+  // canonicalize it to the docs host.
+  const stars = await requestWithHost("ktx.sh", "/stars");
+  assert.ok(
+    !(stars.location ?? "").startsWith("https://docs.kaelio.com"),
+    "the stars dashboard must not be redirected to the docs host",
+  );
+});

website/vercel.json

@@ -1,10 +0,0 @@
-{
-  "redirects": [
-    {
-      "source": "/:path*",
-      "has": [{ "type": "host", "value": "ktx.sh" }],
-      "destination": "https://docs.ktx.sh/:path*",
-      "permanent": true
-    }
-  ]
-}