[yxhuvud]

While more interesting than the first part, it should be noted that the policy does not solve the same problem as the one they had originally, where different fail reasons led to different URLs.

If you only intend to redirect to one url in case of fail, then using normal validations (possibly on a service object implementing ActiveModel::Validations will suffice and produce as simple code as their solution.

Which isn't saying that I dislike it, only that it is quite equivalent with a separate service model without controller integration.

[danso]

Yeah, I agree with you...I think the implication is that the original implementation was bad for various reasons, among them, redirecting to different URLs based on error. But if in fact, that kind of redirection needed to be done (which would seem to be a mild violation of best-OOP practices), then I'd agree, a Policy object that lived outside of the Model and the Controller would be needed.

However, the OP apparently realized in the refactoring that it made more sense to simply have two paths...or setup a convention so that `redirect` can infer the correct error page from the error itself. If the OP had insisted that the Policy keep the path logic, I'm sure DHH would jump all over that as being bad-design-looking-for-a-solution.

[tomblomfield]

Yes - you're absolutely right. We perhaps could have made this trade-off more explicit.

We didn't want the Policy object to know about the redirect paths, so we opted to cut down the number of responses available - we simply redirect_to :back by default, but this can be configured in the controller.