feat(webhooks): add list and granular delete endpoints

- GET /:did/webhooks lists subscriptions for the authenticated owner
  (token field excluded — write-only as elsewhere).
- DELETE /:did/webhooks/:id deletes a single subscription. The query
  scopes on (did, id) so a verified caller cannot delete rows that
  belong to a different DID even with a valid id.

Also extracts the auth gate into requireDidOwnership now that three
endpoints share it.

server.ts

@@ -1,15 +1,44 @@
 import { Application, Router } from "@oak/oak";
 import {
   addWebhookSubscription,
+  deleteWebhookById,
   deleteWebhooksByDid,
   getNotes,
   getNotesByDid,
   getNotesByDids,
+  listWebhooksByDid,
   type WebhookVerb,
 } from "./src/data/db.ts";
 import { authenticateRequest } from "./src/auth/verify.ts";
 import { log } from "./src/log.ts";
 
+type AuthCtx = {
+  request: { headers: { get(key: string): string | null } };
+  response: { status: number; body: unknown };
+};
+
+const requireDidOwnership = async (
+  ctx: AuthCtx,
+  did: string,
+): Promise<boolean> => {
+  let verifiedDid: string;
+  try {
+    verifiedDid = await authenticateRequest(
+      ctx.request.headers.get("Authorization"),
+    );
+  } catch {
+    ctx.response.status = 401;
+    ctx.response.body = { error: "Unauthorized" };
+    return false;
+  }
+  if (verifiedDid !== did) {
+    ctx.response.status = 403;
+    ctx.response.body = { error: "You can only manage your own webhooks" };
+    return false;
+  }
+  return true;
+};
+
 const router = new Router();
 
 const PAGINATION = 20;
@@ -88,23 +117,15 @@ router.post("/notes/feed", async (ctx) => {
 
 const ALLOWED_VERBS = ["create", "delete", "bulk-create"] as const;
 
+router.get("/:did/webhooks", async (ctx) => {
+  const { did } = ctx.params;
+  if (!(await requireDidOwnership(ctx, did))) return;
+  ctx.response.body = listWebhooksByDid(did);
+});
+
 router.post("/:did/webhooks", async (ctx) => {
   const { did } = ctx.params;
-  let verifiedDid: string;
-  try {
-    verifiedDid = await authenticateRequest(
-      ctx.request.headers.get("Authorization"),
-    );
-  } catch {
-    ctx.response.status = 401;
-    ctx.response.body = { error: "Unauthorized" };
-    return;
-  }
-  if (verifiedDid !== did) {
-    ctx.response.status = 403;
-    ctx.response.body = { error: "You can only manage your own webhooks" };
-    return;
-  }
+  if (!(await requireDidOwnership(ctx, did))) return;
   const body = await ctx.request.body.json();
   const { method, url, token, verb } = body ?? {};
   if (!method || !url) {
@@ -129,25 +150,25 @@ router.post("/:did/webhooks", async (ctx) => {
 
 router.delete("/:did/webhooks", async (ctx) => {
   const { did } = ctx.params;
-  let verifiedDid: string;
-  try {
-    verifiedDid = await authenticateRequest(
-      ctx.request.headers.get("Authorization"),
-    );
-  } catch {
-    ctx.response.status = 401;
-    ctx.response.body = { error: "Unauthorized" };
-    return;
-  }
-  if (verifiedDid !== did) {
-    ctx.response.status = 403;
-    ctx.response.body = { error: "You can only manage your own webhooks" };
-    return;
-  }
+  if (!(await requireDidOwnership(ctx, did))) return;
   deleteWebhooksByDid(did);
   ctx.response.status = 204;
 });
 
+router.delete("/:did/webhooks/:id", async (ctx) => {
+  const { did, id } = ctx.params;
+  if (!(await requireDidOwnership(ctx, did))) return;
+  const numericId = Number(id);
+  if (!Number.isInteger(numericId) || numericId <= 0) {
+    ctx.response.status = 400;
+    ctx.response.body = { error: "id must be a positive integer" };
+    return;
+  }
+  const deleted = deleteWebhookById({ did, id: numericId });
+  ctx.response.status = deleted ? 204 : 404;
+  if (!deleted) ctx.response.body = { error: "webhook not found" };
+});
+
 // router.delete("/:did/:rkey", async (ctx) => {
 //   const { did, rkey } = ctx.params;
 //   let verifiedDid: string;

src/data/db.ts

@@ -119,6 +119,23 @@ export const deleteWebhooksByDid = (did: string): void => {
   db.exec("DELETE FROM webhook_subscription WHERE did = ?", did);
 };
 
+export const deleteWebhookById = (
+  { did, id }: { did: string; id: number },
+): boolean => {
+  const result = db.prepare(
+    "DELETE FROM webhook_subscription WHERE did = ? AND id = ?",
+  ).run(did, id);
+  return result > 0;
+};
+
+export const listWebhooksByDid = (
+  did: string,
+): Omit<WebhookSubscriptionRow, "token">[] => {
+  return db.prepare(
+    "SELECT id, did, method, url, verb FROM webhook_subscription WHERE did = ? ORDER BY id DESC",
+  ).all<Omit<WebhookSubscriptionRow, "token">>(did);
+};
+
 export const getWebhooksByDidAndVerb = (
   did: string,
   verb: WebhookVerb,