Modify unauthorized exception

[JaumeS4]

I'm submitting a...

[ ] Regression
[ ] Bug report
[ ] Feature request
[x] Documentation issue or request
[ ] Support request => Please do not submit support request here, instead post your question on Stack Overflow.

Expected behavior

It would be interesting to add documentation/feature to be able to modify the Unauthorized exception when jwt is invalid, has expired...

[popemann]

+1
I would also like to send a custom exception in case of expired/invalid JWT. Just sending an Unauthorised exception is not enough to know whether is because of the token or other reason.

[kamilmysliwiec]

Just wrap method call with try..catch and return an exception tailored to your app's requirements.

[popemann]

@kamilmysliwiec
What method exactly? In case of an expired/invalid JWT token, the controller's method won't be called, so where exactly should I put try...catch ? Sorry if it seems like a dumb question. Maybe you could provide a basic example like in the documentation, it would be appreciated.

[KOflyan]

@JaumeS4 @popemann Possible solution is to use exception filter and substitute your custom exception whenever the UnauthorizedException is fired.

1. Create the filter:

unauthorized-exception.filter.ts

import { ExceptionFilter, Catch, ArgumentsHost, HttpException, UnauthorizedException } from '@nestjs/common';
import { Response } from 'express';
import { UnauthorizedException as MyUnauthorizedException } from '../exception/exception';

@Catch(UnauthorizedException)
export class UnauthorizedExceptionFilter implements ExceptionFilter {

  catch(exception: UnauthorizedException, host: ArgumentsHost): void {
    const ctx = host.switchToHttp();
    const response = ctx.getResponse<Response>();
    let status = exception.getStatus();
    response
      .status(status)
      .json({
        timestamp: new Date().toISOString(),
        error: new MyUnauthorizedException()
      });
  }
}

2. Enable the filter:

main.ts

    app.useGlobalFilters(new UnauthorizedExceptionFilter());

But yea, cleaner way would be to make it possible to override passport fail callback or whatever.

[popemann]

@KOflyan hmm, yeah, this is also nice.
I was also curious about Kamil's solution, 'cause I didn't really understand where that try...catch should be put.