While our previous explorations of Supabase Functions focused on request-response patterns, real-world applications often require executing code asynchronously or on a schedule. Supabase provides robust solutions for both background tasks and scheduled functions, leveraging the power of Edge Functions.
Think of background tasks as operations that don't need to immediately respond to a user. This could include sending welcome emails after a user signs up, processing image uploads, or performing complex data manipulations that might take a while. Scheduled functions, on the other hand, are perfect for recurring operations like generating daily reports, cleaning up old data, or sending out weekly newsletters.
Supabase Functions are built on Deno, a secure runtime for JavaScript and TypeScript. This means you can leverage the full power of these languages to build sophisticated background and scheduled tasks. The core idea is to trigger a function's execution without direct HTTP interaction.
To implement background tasks, we typically trigger a Supabase Function from another part of our application, often a database trigger or a client-side event that doesn't require an immediate server response. The key is that the client or trigger initiating the task doesn't wait for the function to complete. Instead, it just fires it off.
One common pattern is using database webhooks. When a specific event (like an INSERT into a users table) occurs, you can configure a webhook to call your Supabase Function. This function then runs in the background without impacting the user's experience of signing up.
/**
* This function can be triggered by a database webhook.
* It processes a new user signup in the background.
*/
import {
serve,
type ServerEvent,
} from "https://deno.land/std@0.192.0/http/server.ts";
console.log("Background task function started...");
serve(async (req: Request) => {
const body = await req.json();
console.log("Received user data:", body);
// Simulate sending a welcome email
await new Promise(resolve => setTimeout(resolve, 5000));
console.log("Welcome email sent to:", body.record.email);
return new Response(JSON.stringify({ message: "Task processed successfully" }), {
headers: { "Content-Type": "application/json" },
});
});