PubSub HTTP Handler

PubSub HTTP Handler is a simple Typescript/Javascript package that solves serving an HTTP endpoint that can consume PubSub messages. To do this task we utilize the Fastify framework or Google Cloud Functions.

This package was built so that when creating microservices that subscribe to a PubSub-topic, we don't have to implement a server or validate the request.

Quickstart

▶ yarn add pubsub-http-handler

Example with Fastify Server

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);
};

Example with Google Cloud Functions

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

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

export const helloWorld = createPubSubCloudFunctions<MyHandler>(
  ({ data, log }) => {
    log.info(`Hello, ${data.name}`);
  },
);

Read more about configuration here or check out the API documentation

Options

• onError (function, default is undefined). Use to ensure that the function doesn't throw. Warning: Using this option will make the function return 204 regardless.

• parseJson (boolean, default is true). When set to true, uses JSON.parse to parse the data sent through PubSub.

• parser (function, optional). This option can be used to parse data coming from PubSub. The function must return data (this data is passed to the handler, as data). You can optionally throw an exception if the data could not be parsed, which in turn can be caught by onError if you'd like.

We export a function called makePubSubConfig to help with type inference. This is basicly a function that lets you return a function while using parser, which is returned in handler. If you know a way for the types to work without using a function like this, we would love a pull request!

Contributing

We love contributions! 🙏 Bug reports and pull requests are welcome on GitHub.