#Better Auth Implementation in NestJS

11 messages · Page 1 of 1 (latest)

buoyant idol
#

Hello! Is there an example implementation of better-auth in nestjs?

lunar flax
waxen heron
#

I've gotten as far as this:

import { All, Controller, Req, Res } from "@nestjs/common";
import { toNodeHandler } from "better-auth/node";
import { auth } from "@/lib/auth";
import type { Request, Response } from "express";

@Controller("auth")
export class AuthController {
  private readonly handler = toNodeHandler(auth.handler);

  @All("*path")
  async handleAuth(@Req() req: Request, @Res() res: Response) {
    await this.handler(req, res);
  }
}

Which works - almost! It's set up (apparently) successfully with Drizzle and Better Auth. The issue I'm currently running into though, is that for POST requests with a body, I get the following error:

[Nest] 15512  - 19/02/2025, 19:47:37   ERROR [ExceptionsHandler] TypeError: Response body object should not be disturbed or locked      
    at extractBody (node:internal/deps/undici/undici:5518:17)
    at new Request (node:internal/deps/undici/undici:9697:48)
    at getRequest (C:\Users\Matt\Documents\Code\Nest-BetterAuth-Drizzle\node_modules\better-call\src\adapter\request.ts:98:9)
    at AuthController.handler (C:\Users\Matt\Documents\Code\Nest-BetterAuth-Drizzle\node_modules\better-call\src\adapter\node.ts:11:34)
    at AuthController.handleAuth (C:\Users\Matt\Documents\Code\Nest-BetterAuth-Drizzle\src\modules\auth\auth.controller.ts:12:16)      
    at C:\Users\Matt\Documents\Code\Nest-BetterAuth-Drizzle\node_modules\@nestjs\core\router\router-execution-context.js:38:29
    at process.processTicksAndRejections (node:internal/process/task_queues:105:5)
    at async C:\Users\Matt\Documents\Code\Nest-BetterAuth-Drizzle\node_modules\@nestjs\core\router\router-execution-context.js:46:28
    at async C:\Users\Matt\Documents\Code\Nest-BetterAuth-Drizzle\node_modules\@nestjs\core\router\router-proxy.js:9:17
#

If anyone has any info on how I could fix this, I'd be very happy, as I simply can't seem to figure out how to troubleshoot this properly. My hypothesis is that it's getting into errors due to the way Express is internally set up in NestJS - seeing the Better Auth docs requires to register express.json() after registering the Auth endpoint. Not really sure what to do about it though.

image.png
#

I did find a working way, registering the auth endpoint in the main.ts file, although I wish it would be possible in its own module for further expansion and cleaner separation with the rest of the code - maybe someone sees this in the future and can give me advice... Anyway, here's how you can register it in the main.ts file:

import { NestFactory } from "@nestjs/core";
import { AppModule } from "./app.module";
import { toNodeHandler } from "better-auth/node";
import { auth } from "@/lib/auth";

async function bootstrap() {
  const app = (await NestFactory.create(AppModule)).setGlobalPrefix("api");

  app.getHttpAdapter().all("/api/auth/*path", toNodeHandler(auth));

  await app.listen(process.env.PORT ?? 3000);
}
void bootstrap();
lunar flax
twilit badge
serene verge
#

@waxen heron Did you get this working or did you fallback to the package from Thalles?

waxen heron
#

Created some guards/decorators or so to go with it

#

Felt a bit weird, but it worked