migrate-from-v4-to-v5.md

Migrate from v4 to v5

v5 is mainly a refactor of the codebase, to make it more maintainable and improve developer experience. The API is the same, but we have officially removed the createPubSubServer.

We also changed from using @sinclair/typebox to @fastify/type-provider-typebox which probably will not affect most users, this bumped @sinclair/typebox from 0.24 to 0.27.

Replacing createPubSubServer with Fastify instance

The reasoning behind removing createPubSubServer is that it was not really needed. It was a function that created a fastify instance, and then returned a listen function. The fastify instance can be created by the user with almost the same amount of code.

Before

import { createPubSubServer, PubSubHandler } from 'pubsub-http-handler';

interface MyHandler {
  hello: string;
  world: string;
}

const server = async () => {
  const handler: PubSubHandler<MyHandler> = ({ message, data }) => {
    // `message` contains attributes, data (as string), messageId
    // `data` contains a base64 decoded JSON serialized object (type is MyHandler in the example)
    // ...
  };

  const { listen } = await createPubSubServer(handler);
  await listen();
};

After

import Fastify from 'fastify';
import { pubSubFastifyPlugin, PubSubHandler } from 'pubsub-http-handler';

interface MyHandler {
  hello: string;
  world: string;
}

const server = async () => {
  const handler: PubSubHandler<MyHandler> = ({ message, data }) => {
    // `message` contains attributes, data (as string), messageId
    // `data` contains a base64 decoded JSON serialized object (type is MyHandler in the example)
    // ...
  };

  const app = Fastify().withTypeProvider<TypeBoxTypeProvider>();

  app.register(pubSubFastifyPlugin, makePubSubConfig({ handler }));

  await app.listen(8000);
};