Azure Blob Storage

Subscribe files.events.webhook() to a storage account's Event Grid events, in either schema.

Azure Blob Storage publishes BlobCreated and BlobDeleted events through Event Grid. The azure adapter reads both the Event Grid and CloudEvents schemas, and webhook() answers Event Grid’s validation handshake.

import { createRouteHandler } from "files-sdk/next";
import { files } from "@/lib/files";

const webhook = files.events.webhook({
  verify: { token: process.env.STORAGE_WEBHOOK_TOKEN! },
});

export const { POST } = createRouteHandler(webhook);
// Only for the CloudEvents schema, which handshakes with OPTIONS:
export const OPTIONS = (req: Request) => webhook.handle(req);

Event Grid doesn’t sign deliveries, so put a secret in the endpoint URL (?token=). The subscription can’t be created until the endpoint is live, because Event Grid validates it first.

az provider register --namespace Microsoft.EventGrid  # first use in a subscription
storageid=$(az storage account show --name ACCOUNT --resource-group RG \
  --query id --output tsv)
az eventgrid event-subscription create --name uploads \
  --source-resource-id "$storageid" \
  --endpoint "https://app.example.com/api/storage-events?token=$STORAGE_WEBHOOK_TOKEN" \
  --included-event-types Microsoft.Storage.BlobCreated Microsoft.Storage.BlobDeleted \
  --subject-begins-with /blobServices/default/containers/my-container/

Keep the trailing slash in --subject-begins-with, so other containers whose names start the same way don’t match. Add --event-delivery-schema cloudeventschemav1_0 for CloudEvents. To send the secret as a header instead of in the URL, use --delivery-attribute-mapping Authorization static "Bearer $STORAGE_WEBHOOK_TOKEN" true.

What maps to what

The key is the blob name from the event’s subject; the container becomes the event’s bucket, and events() keeps only the adapter’s own container by default, so a system topic shared by several containers delivers only yours. Pass events({ bucket: "my-container" }) to pick another, or bucket: false for all of them.