Use case

For Lambda function URLs it is possible to stream response payloads back to the client. While Event Handler does not currently support Lambda function URLs, we will in the future.

We need to investigate how this mode of response impacts the API we plan to launch at GA.

Solution/User Experience

We want an experience with as little friction as possible but there are a lot of unknowns here so this is by no means the definitive DX:

import { Router } from '@aws-lambda-powertools/event-handler/experimental-rest';
import type { Context } from 'aws-lambda';

const app = new Router({streaming: true});

app.get('/stream', async () => {
  const myStream = createWriteStream()
  myStream.write("Hello ");
  myStream.write("world ");
  myStream.write("from ");
  myStream.write("Lambda!");
  myStream.end();
  return myStream;
});

export const handler = async (event: unknown, context: Context) => {
  return app.resolve(event, context);
};

Alternative solutions

Acknowledgment

• This feature request meets Powertools for AWS Lambda (TypeScript) Tenets
• Should this be considered in other Powertools for AWS Lambda languages? i.e. Python, Java, and .NET

Future readers

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