Support API Gateway Response Streaming

[filipe-cantarelli]

Prerequisites

• I have written a descriptive issue title
• I have searched existing issues to ensure the feature has not already been requested

🚀 Feature Proposal

Introduce a new disableBase64Encoding option that disables Base64 encoding and ensures the isBase64Encoded property is not included in the response.

I implemented this in my fork here:
https://github.com/filipe-cantarelli/aws-lambda-fastify

Since this adds a new option, I wanted to check with the community first and get some feedback before opening a pull request.

Motivation

API Gateway response streaming does not support the isBase64Encoded property (see: https://aws.amazon.com/blogs/compute/building-responsive-apis-with-amazon-api-gateway-response-streaming/
).

A practical workaround is to introduce a disableBase64Encoding option, which disables Base64 encoding and prevents the isBase64Encoded property from being included in the response.

Example

import { pipeline } from 'node:stream/promises';
import awsLambdaFastify from '@fastify/aws-lambda';
import { app } from './app.js';


const proxy = awsLambdaFastify(app, { payloadAsStream: true, disableBase64Encoding: true })
export const handler = awslambda.streamifyResponse(async (event, responseStream, context) => {
    const { meta, stream } = await proxy(event, context)
    responseStream = awslambda.HttpResponseStream.from(responseStream, meta)
    console.error(meta);
    await pipeline(stream, responseStream)
})
await app.ready() // https://github.com/fastify/aws-lambda-fastify/issues/89

[adrai]

Did not had time to test the new streaming capabilities... but sounds good.
Please feel free to open a PR.
Please add some dedicated tests.

[adrai]

btw. maybe we could set disableBase64Encoding to true by default if payloadAsStream = true and the using api-gateway (not alb)...?

we could check for requestContext?.alb: https://docs.aws.amazon.com/lambda/latest/dg/services-alb.html

What do you think?

[filipe-cantarelli]

btw. maybe we could set disableBase64Encoding to true by default if payloadAsStream = true and the using api-gateway (not alb)...?

we could check for requestContext?.alb: https://docs.aws.amazon.com/lambda/latest/dg/services-alb.html

What do you think?

I think that works, as people would often forget to add this. But we still want to have the option to override it, right?

[adrai]

I think that works, as people would often forget to add this. But we still want to have the option to override it, right?

yes

[filipe-cantarelli]

#288