Simplify creating RFC 7807 responses from functional endpoints #29462
Description
This is currently possible, but could be better:
RouterFunctions.route() .GET("/path", request -> { throw new IllegalArgumentException("..."); }) .onError(IllegalArgumentException.class, (ex, serverRequest) -> { ErrorResponse errorResponse = ErrorResponse.createFor( (Exception) ex, HttpStatus.BAD_REQUEST, null, "Invalid input", null, null); return ServerResponse.status(errorResponse.getStatusCode()) .body(errorResponse.getBody()); }) .build()We could add a ServerResponse#from(ErrorResponse) shortcut, and also provide a builder for ErrorResponse.