feat: Enhance Balance Subscriptions webhook handling

- Add support for creating new webhooks with optional labels
- Allow using existing webhooks by ID
- Validate webhook event type and revocation status
- Improve error handling for webhook creation and selection

src/server/routes/balance-subscriptions/add.ts

@@ -3,6 +3,7 @@ import type { FastifyInstance } from "fastify";
 import { StatusCodes } from "http-status-codes";
 import { createBalanceSubscription } from "../../../shared/db/balance-subscriptions/create-balance-subscription";
 import { insertWebhook } from "../../../shared/db/webhooks/create-webhook";
+import { getWebhook } from "../../../shared/db/webhooks/get-webhook";
 import { balanceSubscriptionConfigSchema } from "../../../shared/schemas/balance-subscription-config";
 import { WebhooksEventTypes } from "../../../shared/schemas/webhooks";
 import { createCustomError } from "../../middleware/error";
@@ -13,19 +14,36 @@ import { getChainIdFromChain } from "../../utils/chain";
 import { isValidWebhookUrl } from "../../utils/validator";
 import { balanceSubscriptionSchema, toBalanceSubscriptionSchema } from "../../schemas/balance-subscription";
 
-const requestBodySchema = Type.Object({
-  chain: chainIdOrSlugSchema,
-  contractAddress: Type.Optional(AddressSchema),
-  walletAddress: AddressSchema,
-  config: balanceSubscriptionConfigSchema,
-  webhookUrl: Type.Optional(
+const webhookUrlSchema = Type.Object({
+  webhookUrl: Type.String({
+    description: "Webhook URL to create a new webhook",
+    examples: ["https://example.com/webhook"],
+  }),
+  webhookLabel: Type.Optional(
     Type.String({
-      description: "Webhook URL",
-      examples: ["https://example.com/webhook"],
+      description: "Optional label for the webhook when creating a new one",
+      examples: ["My Balance Subscription Webhook"],
+      minLength: 3,
     }),
   ),
 });
 
+const webhookIdSchema = Type.Object({
+  webhookId: Type.Integer({
+    description: "ID of an existing webhook to use",
+  }),
+});
+
+const requestBodySchema = Type.Intersect([
+  Type.Object({
+    chain: chainIdOrSlugSchema,
+    contractAddress: Type.Optional(AddressSchema),
+    walletAddress: AddressSchema,
+    config: balanceSubscriptionConfigSchema,
+  }),
+  Type.Union([webhookUrlSchema, webhookIdSchema]),
+]);
+
 const responseSchema = Type.Object({
   result: balanceSubscriptionSchema,
 });
@@ -49,13 +67,15 @@ export async function addBalanceSubscriptionRoute(fastify: FastifyInstance) {
       },
     },
     handler: async (request, reply) => {
-      const { chain, contractAddress, walletAddress, config, webhookUrl } = request.body;
-
+      const { chain, contractAddress, walletAddress, config } = request.body;
       const chainId = await getChainIdFromChain(chain);
 
-      // Create the webhook (if provided).
-      let webhookId: number | undefined;
-      if (webhookUrl) {
+      let finalWebhookId: number | undefined;
+
+      // Handle webhook creation or validation
+      if ("webhookUrl" in request.body) {
+        // Create new webhook
+        const { webhookUrl, webhookLabel } = request.body;
         if (!isValidWebhookUrl(webhookUrl)) {
           throw createCustomError(
             "Invalid webhook URL. Make sure it starts with 'https://'.",
@@ -66,19 +86,45 @@ export async function addBalanceSubscriptionRoute(fastify: FastifyInstance) {
 
         const webhook = await insertWebhook({
           eventType: WebhooksEventTypes.BALANCE_SUBSCRIPTION,
-          name: "(Auto-generated)",
+          name: webhookLabel || "(Auto-generated)",
           url: webhookUrl,
         });
-        webhookId = webhook.id;
+        finalWebhookId = webhook.id;
+      } else {
+        // Validate existing webhook
+        const { webhookId } = request.body;
+        const webhook = await getWebhook(webhookId);
+        if (!webhook) {
+          throw createCustomError(
+            `Webhook with ID ${webhookId} not found.`,
+            StatusCodes.NOT_FOUND,
+            "NOT_FOUND",
+          );
+        }
+        if (webhook.eventType !== WebhooksEventTypes.BALANCE_SUBSCRIPTION) {
+          throw createCustomError(
+            `Webhook with ID ${webhookId} has incorrect event type. Expected '${WebhooksEventTypes.BALANCE_SUBSCRIPTION}' but got '${webhook.eventType}'.`,
+            StatusCodes.BAD_REQUEST,
+            "BAD_REQUEST",
+          );
+        }
+        if (webhook.revokedAt) {
+          throw createCustomError(
+            `Webhook with ID ${webhookId} has been revoked.`,
+            StatusCodes.BAD_REQUEST,
+            "BAD_REQUEST",
+          );
+        }
+        finalWebhookId = webhookId;
       }
 
-      // Create the balance subscription.
+      // Create the balance subscription
       const balanceSubscription = await createBalanceSubscription({
         chainId: chainId.toString(),
         contractAddress: contractAddress?.toLowerCase(),
         walletAddress: walletAddress.toLowerCase(),
         config,
-        webhookId,
+        webhookId: finalWebhookId,
       });
 
       reply.status(StatusCodes.OK).send({