Triggers & Edge Functions

Storage objects fire the standard trigger lifecycle - every CRUD event has a BEFORE and AFTER hook on both the storage.Object label and the storage.objects collection. This lets you post-process uploads (thumbnail, virus-scan, OCR), enforce custom invariants, or kick off downstream workflows.

Available events

Example: auto-thumbnail

-- Drop a 200x200 thumbnail into a sibling bucket on every avatar upload.
CREATE TRIGGER avatar_thumbnail
  AFTER INSERT ON LABEL `storage.Object`
  WHEN row.bucket_id = "avatars" AND row.mime_type STARTS WITH "image/"
  EXECUTE EDGE FUNCTION generate_thumbnail
    WITH ARGS {
      source_bucket: "avatars",
      source_path: row.path,
      dest_bucket: "thumbnails",
      width: 200,
      height: 200
    };

Edge function recipe (TypeScript)

// edge_functions/generate_thumbnail.ts
import { AnvilClient } from "anvilent";

export async function handler(args: {
  source_bucket: string;
  source_path: string;
  dest_bucket: string;
  width: number;
  height: number;
}) {
  // service_role JWT is injected by the runtime - bypasses RLS.
  const client = anvil.client;

  // Re-encode via the built-in render endpoint.
  const url = client.storage
    .from(args.source_bucket)
    .getPublicUrl(args.source_path, {
      transform: { width: args.width, height: args.height, format: "webp" },
    }).publicUrl;

  const blob = await fetch(url).then((r) => r.blob());

  await client.storage
    .from(args.dest_bucket)
    .upload(args.source_path.replace(/\.[^.]+$/, ".webp"), blob, {
      contentType: "image/webp",
      upsert: true,
    });
}

Other patterns