AWS API Gateway V1 streaming

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An example on how to enable streaming for API Gateway REST API routes.

sst.config.ts

api.route("GET /", {
  handler: "index.handler",
  streaming: true,
});

The handler uses the native awslambda.streamifyResponse and awslambda.HttpResponseStream.from to stream responses through API Gateway.

index.ts

export const handler = awslambda.streamifyResponse(
  async (event, stream) => {
    stream = awslambda.HttpResponseStream.from(stream, {
      statusCode: 200,
      headers: {
        "Content-Type": "text/plain; charset=UTF-8",
        "X-Content-Type-Options": "nosniff",
      },
    });

    stream.write("Hello ");
    await new Promise((resolve) => setTimeout(resolve, 3000));
    stream.write("World");

    stream.end();
  },
);

sst.config.ts

const api = new sst.aws.ApiGatewayV1("MyApi");
api.route("GET /", {
  handler: "index.handler",
  streaming: true,
});
api.route("GET /hono", {
  handler: "hono.handler",
  streaming: true,
});
api.deploy();

hono.ts

import { Hono } from "hono";
import { streamText } from "hono/streaming";
import { streamHandle } from "hono/aws-lambda";

const app = new Hono().get("/hono", (c) => {
  return streamText(c, async (stream) => {
    await stream.writeln("Hello");
    await stream.sleep(3000);
    await stream.writeln("World");
  });
});

export const handler = streamHandle(app);

View the full example.