feat: add webhook_subscription table and CRUD endpoints

- Migration: CREATE TABLE webhook_subscription (id, did, method, url) with index on did
- db.ts: addWebhookSubscription and deleteWebhooksByDid helpers
- server.ts: POST /:did/webhooks (201) and DELETE /:did/webhooks (204)

server.ts

@@ -1,5 +1,10 @@
 import { Application, Router } from "@oak/oak";
-import { getNotes, getNotesByDid } from "./src/data/db.ts";
+import {
+  addWebhookSubscription,
+  deleteWebhooksByDid,
+  getNotes,
+  getNotesByDid,
+} from "./src/data/db.ts";
 import { log } from "./src/log.ts";
 
 const router = new Router();
@@ -23,6 +28,26 @@ router.get("/:did/notes", (ctx) => {
   ctx.response.body = getNotesByDid(did, cursor, limit);
 });
 
+router.post("/:did/webhooks", async (ctx) => {
+  const { did } = ctx.params;
+  const body = await ctx.request.body.json();
+  const { method, url } = body ?? {};
+  if (!method || !url) {
+    ctx.response.status = 400;
+    ctx.response.body = { error: "method and url are required" };
+    return;
+  }
+  const subscription = addWebhookSubscription({ did, method, url });
+  ctx.response.status = 201;
+  ctx.response.body = subscription;
+});
+
+router.delete("/:did/webhooks", (ctx) => {
+  const { did } = ctx.params;
+  deleteWebhooksByDid(did);
+  ctx.response.status = 204;
+});
+
 // router.delete("/:did/:rkey", async (ctx) => {
 //   const { did, rkey } = ctx.params;
 //   let verifiedDid: string;

src/data/db.ts

@@ -67,6 +67,31 @@ export const saveCursor = (cursor: number) => {
   );
 };
 
+type WebhookSubscriptionRow = {
+  id: number;
+  did: string;
+  method: string;
+  url: string;
+};
+
+export const addWebhookSubscription = (
+  { did, method, url }: Omit<WebhookSubscriptionRow, "id">,
+): WebhookSubscriptionRow => {
+  db.exec(
+    "INSERT INTO webhook_subscription (did, method, url) VALUES (?, ?, ?)",
+    did,
+    method,
+    url,
+  );
+  return db.prepare(
+    "SELECT id, did, method, url FROM webhook_subscription WHERE id = last_insert_rowid()",
+  ).get<WebhookSubscriptionRow>()!;
+};
+
+export const deleteWebhooksByDid = (did: string): void => {
+  db.exec("DELETE FROM webhook_subscription WHERE did = ?", did);
+};
+
 export const upsertNote = (note: Note) => {
   const now = new Date().toISOString();
   db.exec(

src/migrations/init.ts

@@ -18,4 +18,18 @@ db.exec(`
   );
 `);
 
+db.exec(`
+  CREATE TABLE IF NOT EXISTS webhook_subscription (
+    id     INTEGER PRIMARY KEY,
+    did    TEXT NOT NULL,
+    method TEXT NOT NULL,
+    url    TEXT NOT NULL
+  );
+`);
+
+db.exec(`
+  CREATE INDEX IF NOT EXISTS idx_webhook_subscription_did
+    ON webhook_subscription(did);
+`);
+
 db.close();