How to change the default error output in restify

Question

Is there any way that I can change the default error output? Say I'm going to change the rest error output:

{
    "code": "InvalidArgumentError",
    "message": "blah blah..."
}

to:

{
    "code": 10001,
    "message": "blah blah",
    "extraMsg": "blah blah"
}

Here are some of my ideas:

• Listen to the error events.
  It seems like not all the RestError have emitted extra events (like NotFound, MethodNotAllowed, VersionNotAllowed... do). So I can't catch all the errors to rewrite them.

• Listen to an event before response data sent.
  I look through the official documents and have found nothing relative.

• Modify the implementation of the RestError class.
  Well it's obviously not a good approach.

Any other ideas?

Answer 1

Finally I provide a customized JSON formatter to get what I want:

var server = restify.createServer( {
    formatters: {
        'application/json': function customizedFormatJSON( req, res, body ) {
            // Copied from restify/lib/formatters/json.js

            if ( body instanceof Error ) {
                // snoop for RestError or HttpError, but don't rely on
                // instanceof
                res.statusCode = body.statusCode || 500;

                if ( body.body ) {
                    body = {
                        code: 10001,
                        scode: body.body.code,
                        msg: body.body.message
                    };
                } else {
                    body = {
                        code: 10001,
                        msg: body.message
                    };
                }
            } else if ( Buffer.isBuffer( body ) ) {
                body = body.toString( 'base64' );
            }

            var data = JSON.stringify( body );
            res.setHeader( 'Content-Length', Buffer.byteLength( data ) );

            return data;
        }
    }
} );