add webfinger and routes boilerplate

src/routes/well-known/webfinger.ts

@@ -0,0 +1,80 @@
+import type { FastifyReply, FastifyRequest, RouteOptions } from "fastify";
+import { IsNull } from "typeorm";
+
+import log from "../../log.js";
+import MercuryDataSource from "../../db/index.js";
+import { Blog } from "../../db/entities/blog.js";
+import { BASE_URL } from "../../config.js";
+
+const route: RouteOptions = {
+  method: "GET",
+  url: "/.well-known/webfinger",
+  handler: async (req, res) => {
+    // TypeScript complains if we just use plain `req.query` :(
+    const encodedResource = (req.query as { resource: string }).resource;
+
+    if (!encodedResource || typeof encodedResource !== "string") {
+      res.status(400).send({
+        error: "resource query parameter is missing or invalid",
+      });
+      return;
+    }
+    const resource = decodeURIComponent(encodedResource);
+
+    log.debug("Handling WebFinger request for %s", resource);
+
+    if (resource.startsWith("acct:")) {
+      await handleAcctWebfinger(req, res, resource);
+      return;
+    }
+
+    res.status(500).send({ error: "Unhandled WebFinger resource type" });
+  },
+};
+
+export default route;
+
+async function handleAcctWebfinger(
+  req: FastifyRequest,
+  res: FastifyReply,
+  resource: string
+): Promise<void> {
+  const [username, domain] = resource.slice("acct:".length).split("@");
+  if (domain !== process.env.DOMAIN) {
+    res.status(404).send({
+      error: "Account not found",
+    });
+    return;
+  }
+
+  const blog = await MercuryDataSource.getRepository(Blog).findOneBy({
+    username: username,
+    host: IsNull(),
+  });
+  if (!blog) {
+    res.status(404).send({
+      error: "Account not found",
+    });
+    return;
+  }
+
+  res.send({
+    subject: resource,
+    aliases: [
+      `${BASE_URL}/@${blog.username}`,
+      `${BASE_URL}/blogs/${blog.username}`,
+    ],
+    links: [
+      {
+        rel: "http://webfinger.net/rel/profile-page",
+        type: "text/html",
+        href: `${BASE_URL}/@${blog.username}`,
+      },
+      {
+        rel: "self",
+        type: "application/activity+json",
+        href: `${BASE_URL}/blogs/${blog.username}`,
+      },
+    ],
+  });
+}