AWS Lambda + API Gateway Adapter - Trpc

AWS Lambda adapter

The AWS Lambda adapter is supported for API Gateway Rest API(v1) and HTTP API(v2) use cases.

Example app

<table> <thead> <tr> <th>Description</th> <th>Links</th> </tr> </thead> <tbody> <tr> <td>API Gateway with NodeJS client.</td> <td> <ul> <li><a href="https://github.com/trpc/trpc/tree/main/examples/lambda-api-gateway">Source</a></li> </ul> </td> </tr> </tbody> </table>

How to add tRPC

1. Install deps

bash

yarn add @trpc/server

2. Create a tRPC router

Implement your tRPC router. A sample router is given below:

import { initTRPC } from '@trpc/server';
import { z } from 'zod';

export const t = initTRPC.create();

const appRouter = t.router({
  getUser: t.procedure.input(z.string()).query((opts) => {
    opts.input; // string
    return { id: opts.input, name: 'Bilbo' };
  }),
});

// export type definition of API
export type AppRouter = typeof appRouter;

3. Use the Amazon API Gateway adapter

tRPC includes an adapter for API Gateway out of the box. This adapter lets you run your routes through the API Gateway handler.

import { CreateAWSLambdaContextOptions, awsLambdaRequestHandler } from '@trpc/server/adapters/aws-lambda';

const appRouter = /* ... */;

// created for each request
const createContext = ({
  event,
  context,
}: CreateAWSLambdaContextOptions<APIGatewayProxyEventV2>) => ({}) // no context
type Context = Awaited<ReturnType<typeof createContext>>;

export const handler = awsLambdaRequestHandler({
  router: appRouter,
  createContext,
})

Build & deploy your code, now use your API Gateway URL to call your function.

Endpoint	HTTP URI
`getUser`	`GET https://<execution-api-link>/getUser?input=INPUT`

where INPUT is a URI-encoded JSON string. |

A word about payload format version

API Gateway has two different event data formats when it invokes a Lambda. For REST APIs they should be version "1.0"(APIGatewayProxyEvent), but you can choose which for HTTP APIs by stating either version "1.0" or "2.0".

Version 1.0: APIGatewayProxyEvent
Version 2.0: APIGatewayProxyEventV2

To infer what version you might have, supply the context as following:

function createContext({
  event,
  context,
}: CreateAWSLambdaContextOptions<APIGatewayProxyEvent>) {
  ...
}

// CreateAWSLambdaContextOptions<APIGatewayProxyEvent> or CreateAWSLambdaContextOptions<APIGatewayProxyEventV2>