Tsoa: authenticationMiddleware return error as JSON directly

Created on 8 Oct 2018 · 3Comments · Source: lukeautry/tsoa

Hello,
is there any way to return a JSON object from the authenticationMiddleware to the caller without changing the template? In some cases I just want to return a plain JSON object to the client to tell the client the reason why the authentication failed and can not work with the generic 401 return.

Best regards

Source

caringdeveloper

Most helpful comment

@Peekaboo1337 The pattern I use is to throw errors, and I have a special ServerError type with various properties.

Using express, I create this handler:

app.use((err: any, _req: express.Request, res: express.Response, next: express.NextFunction) => {
    const status = err.status || 500;
    const body: any = {
      fields: err.fields || undefined,
      message: err.message || 'An error occurred during the request.',
      name: err.name,
      status,
      type: err.type || ErrorType.Unknown
    };
    res.status(status).json(body);
    next();
  });

server-error.ts (ErrorType is an enum)

export class ServerError extends Error {
  constructor(
    message: string,
    public readonly status = 500,
    public readonly type: ErrorType = ErrorType.Unknown
  ) {
    super(message);
  }
}

Controller usage:

throw new ServerError('this is a message', HttpStatusCode.NotFound, ErrorType.MyCustomErrorType)

lukeautry on 10 Oct 2018

👍6

All 3 comments

@Peekaboo1337 The pattern I use is to throw errors, and I have a special ServerError type with various properties.

Using express, I create this handler:

app.use((err: any, _req: express.Request, res: express.Response, next: express.NextFunction) => {
    const status = err.status || 500;
    const body: any = {
      fields: err.fields || undefined,
      message: err.message || 'An error occurred during the request.',
      name: err.name,
      status,
      type: err.type || ErrorType.Unknown
    };
    res.status(status).json(body);
    next();
  });

server-error.ts (ErrorType is an enum)

export class ServerError extends Error {
  constructor(
    message: string,
    public readonly status = 500,
    public readonly type: ErrorType = ErrorType.Unknown
  ) {
    super(message);
  }
}

Controller usage:

throw new ServerError('this is a message', HttpStatusCode.NotFound, ErrorType.MyCustomErrorType)

lukeautry on 10 Oct 2018

👍6

@lukeautry This looks awesome. Thanks a lot! Will implement!

caringdeveloper on 10 Oct 2018

Just commenting to say this helped me out tremendously! This advice could probably be placed in the main documentation since a lot of developers probably want the functionality to pass back a custom error message.