Add shared printful webhook secret for authentication

apps/api/src/scripts/register-webhooks.ts

@@ -3,7 +3,7 @@ import { env } from "../util";
 
 const DOMAIN = "dev.api.bladeandbrawn.com";
 
-const PRINTFUL_WEBHOOK_URL = `http://${DOMAIN}/webhooks/printful`;
+const PRINTFUL_WEBHOOK_URL = `http://${DOMAIN}/webhooks/printful?secret=${env.PRINTFUL_WEBHOOK_SECRET}`;
 const WEBFLOW_WEBHOOK_URL = `https://${DOMAIN}/webhooks/webflow`;
 
 function printError(err: unknown): never {

apps/api/src/server.ts

@@ -322,8 +322,11 @@ export const app = new Elysia()
     )
 
     // WEBHOOKS
-    .post("/webhooks/printful", async ({ body }) => {
+    .post("/webhooks/printful", async ({ body, query }) => {
         // https://webflow.com/integrations/printful
+        const verified = crypto.timingSafeEqual(Buffer.from(query.secret, "hex"), Buffer.from(env.PRINTFUL_WEBHOOK_SECRET, "hex"));
+        if (!verified) throw status(400, "Invalid secret");
+
         const payload = body as Printful.Webhook.EventPayload;
 
         switch (payload.type) {
@@ -360,6 +363,9 @@ export const app = new Elysia()
                 const shipment = payload.data.shipment;
                 log.info({ wOrderId, carrier: shipment.carrier, tracking: shipment.tracking_number }, "printful webhook: package shipped");
 
+                // TODO: possible to have multiple packages shipped
+                // order should NOT be immediately fulfulled in that case
+
                 await s.Commerce.Apparel.Orders.Queue.enqueue({
                     type: "apparel_order_fulfill",
                     source: "printful",
@@ -371,7 +377,7 @@ export const app = new Elysia()
             default:
                 log.warn({ type: (payload as any).type }, "printful webhook: unhandled event type");
         }
-    })
+    }, { query: t.Object({ secret: t.String() }) })
     .post("/webhooks/webflow", async ({ request, body }) => {
         if (!s.Commerce.Webflow.Util.verifyWebflowSignature(request, body))
             throw status(400, "Invalid signature");

apps/api/src/util.ts

@@ -11,6 +11,7 @@ export const log = pino({
 export const env = {
     PRINTFUL_AUTH: requireEnv("PRINTFUL_AUTH"),
     PRINTFUL_STORE_ID: requireEnv("PRINTFUL_STORE_ID"),
+    PRINTFUL_WEBHOOK_SECRET: requireEnv("PRINTFUL_WEBHOOK_SECRET"),
     WEBFLOW_SITE_ID: requireEnv("WEBFLOW_SITE_ID"),
     WEBFLOW_COLLECTION_SKUS_ID: requireEnv("WEBFLOW_COLLECTION_SKUS_ID"),
     WEBFLOW_COLLECTION_PRODUCTS_ID: requireEnv("WEBFLOW_COLLECTION_PRODUCTS_ID"),