Body-parser errors always transformed to 500

[tomasAlabes]

Bug Report

Current behavior

If you send a payload that is too big for body-parser, it should respond with a HTTP code 413. But Nest'sBase Exception Filter is considering BP's exception as an unknown error, hence wrapping it in a 500 Internal Server Error.

Input Code

Vanilla Nest app with body-parser enabled. I can't paste the "too big" request.

Expected behavior

As body-parser and cors are part of Nest core functionality, the errors thrown by them should be honored by the app.

Possible Solution

Special check for cors/body-parser exceptions?
A special exception handler that comes with platform-express that understands express middleware?
Duck typing to see if the exception comes with a http status or error code?

Environment

Nest version: 7.4.2

For Tooling issues:

• Node version: 12.18.3
• Platform: Mac

Others:

Using @nestjs/graphql but it doesn't even get to that layer.

PayloadTooLargeError: request entity too large
    at readStream (/Users/path/to/repo/node_modules/raw-body/index.js:155:17)
    at getRawBody (/Users/path/to/repo/node_modules/raw-body/index.js:108:12)
    at read (/Users/path/to/repo/node_modules/body-parser/lib/read.js:77:3)
    at jsonParser (/Users/path/to/repo/node_modules/body-parser/lib/types/json.js:135:5)
    at Layer.handle [as handle_request] (/Users/path/to/repo/node_modules/express/lib/router/layer.js:95:5)
    at trim_prefix (/Users/path/to/repo/node_modules/express/lib/router/index.js:317:13)
    at /Users/path/to/repo/node_modules/express/lib/router/index.js:284:7
    at Function.process_params (/Users/path/to/repo/node_modules/express/lib/router/index.js:335:12)
    at next (/Users/path/to/repo/node_modules/express/lib/router/index.js:275:10)
    at cors (/Users/path/to/repo/node_modules/cors/lib/index.js:188:7)

[tomasAlabes]

From @jmcdo29 in discord:

this is something I've been thinking about since your raised the issue the first time. I could think of a way to make it work, but it may take me some time to getting some code for it. Until then, you could write your own Exception Filter that extends Nest's BaseExceptionFilter, or you could just write one from scratch 🙂

My filter until this is added to the framework: https://gist.github.com/tomasAlabes/249229f97e22774b4ab9682105ce2ca6

[makhataibar]

`
import { NextFunction, Request, Response } from 'express';
import { json, OptionsJson } from 'body-parser';

export const jsonBodyParser = (options?: OptionsJson) => (
req: Request,
res: Response,
next: NextFunction,
) => {
json(options)(req, res, err => {
if (err) {
res.status(err.status).json(err);
} else {
next();
}
});
};

`

[heavenkiller2018]

how to fix it ? "request entity too large"

[makhataibar]

how to fix it ? "request entity too large"

It’s custom body parser middleware

[kamilmysliwiec]

Let's track this here #5990