Dart - bucket.on()

Create a new bucket notification trigger when certain files are created or deleted.

import 'package:nitric_sdk/nitric.dart';
import 'package:nitric_sdk/resources.dart';

// Create a readable, writable, and deletable reference to an 'assets' bucket
final assets = Nitric.bucket("assets").allow([
  BucketPermission.read,
]);

// The request will contain the name of the file `key` and the type of event `type`
assets.on(BlobEventType.delete, '*', (ctx) async {
  print("A file named ${ctx.req.file.key} was deleted");

  return ctx;
});

assets.on(BlobEventType.write, '/images/cat', (ctx) async {
  print("A cat image was created");

  return ctx;
});

assets.on(BlobEventType.write, '/images/dog', (ctx) async {
  final dogImage = await ctx.req.file.read();

  print(dogImage)

  return ctx;
});

Parameters

Name
blobEventType
Required
Required
Type
BlobEventType.write or BlobEventType.delete
Description
The notification type for a triggered event, either on a file write or a file delete.
Name
keyPrefixFilter
Required
Required
Type
String
Description
The file prefix filter that must match for a triggered event. If multiple filters overlap across notifications, an error will be thrown when registering the resource.
Name
middleware
Required
Required
Type
BlobEventHandler
Description
The middleware (code) to be triggered by the bucket notification being triggered.

Available trigger types:

BlobEventType.write

Run when a file in the bucket is created using: file.write()

BlobEventType.delete

Run when a file in the bucket is deleted using: file.delete()

Trigger type cloud mapping

Permission	AWS	GCP	Azure
BlobEventType.write	s3:ObjectCreated:*	OBJECT_FINALIZE	Microsoft.Storage.BlobCreated
BlobEventType.delete	s3:ObjectRemoved:*	OBJECT_DELETE	Microsoft.Storage.BlobDeleted