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Raw body

One of the most common use-case for having access to the raw request body is performing webhook signature verifications. Usually to perform webhook signature validations the unserialized request body is required to calculate an HMAC hash.

Warning This feature can be used only if the built-in global body parser middleware is enabled, ie., you must not pass bodyParser: false when creating the app.

Use with Express#

First enable the option when creating your Nest Express application:

import { NestFactory } from '@nestjs/core';
import type { NestExpressApplication } from '@nestjs/platform-express';
import { AppModule } from './app.module';

// in the "bootstrap" function
const app = await NestFactory.create<NestExpressApplication>(AppModule, {
  rawBody: true,
});
await app.listen(process.env.PORT ?? 3000);

To access the raw request body in a controller, a convenience interface RawBodyRequest is provided to expose a rawBody field on the request: use the interface RawBodyRequest type:

import { Controller, Post, RawBodyRequest, Req } from '@nestjs/common';
import { Request } from 'express';

@Controller('cats')
class CatsController {
  @Post()
  create(@Req() req: RawBodyRequest<Request>) {
    const raw = req.rawBody; // returns a `Buffer`.
  }
}

Registering a different parser#

By default, only json and urlencoded parsers are registered. If you want to register a different parser on the fly, you will need to do so explicitly.

For example, to register a text parser, you can use the following code:

app.useBodyParser('text');

Warning Ensure that you are providing the correct application type to the NestFactory.create call. For Express applications, the correct type is NestExpressApplication. Otherwise the .useBodyParser method will not be found.

Body parser size limit#

If your application needs to parse a body larger than the default 100kb of Express, use the following:

app.useBodyParser('json', { limit: '10mb' });

The .useBodyParser method will respect the rawBody option that is passed in the application options.

Use with Fastify#

First enable the option when creating your Nest Fastify application:

import { NestFactory } from '@nestjs/core';
import {
  FastifyAdapter,
  NestFastifyApplication,
} from '@nestjs/platform-fastify';
import { AppModule } from './app.module';

// in the "bootstrap" function
const app = await NestFactory.create<NestFastifyApplication>(
  AppModule,
  new FastifyAdapter(),
  {
    rawBody: true,
  },
);
await app.listen(process.env.PORT ?? 3000);

To access the raw request body in a controller, a convenience interface RawBodyRequest is provided to expose a rawBody field on the request: use the interface RawBodyRequest type:

import { Controller, Post, RawBodyRequest, Req } from '@nestjs/common';
import { FastifyRequest } from 'fastify';

@Controller('cats')
class CatsController {
  @Post()
  create(@Req() req: RawBodyRequest<FastifyRequest>) {
    const raw = req.rawBody; // returns a `Buffer`.
  }
}

Registering a different parser#

By default, only application/json and application/x-www-form-urlencoded parsers are registered. If you want to register a different parser on the fly, you will need to do so explicitly.

For example, to register a text/plain parser, you can use the following code:

app.useBodyParser('text/plain');

Warning Ensure that you are providing the correct application type to the NestFactory.create call. For Fastify applications, the correct type is NestFastifyApplication. Otherwise the .useBodyParser method will not be found.

Body parser size limit#

If your application needs to parse a body larger than the default 1MiB of Fastify, use the following:

const bodyLimit = 10_485_760; // 10MiB
app.useBodyParser('application/json', { bodyLimit });

The .useBodyParser method will respect the rawBody option that is passed in the application options.