[pothibo]

Just food for thoughts, I forked DHH's implementation and modified it to support a bigger structure (so you can keep stuff in different files/class). I haven't tested the file so it may contains bugs, I apologize if it does.

The file name contains dash(-) replace them with slash(/) as github doesn't like path.

https://gist.github.com/pothibo/9673715

I hope you like it ;)

Edit: It had a shit loads of typos, I believe I have fixed most of them.

[dhh]

Love when people play code ping pong. There's too much talk and not enough play in these threads. But I have to ask you, do you really think that splitting out those two classes improved things for the example? Or was this just future coding for possibly-maybe extension points? Because from where I'm sitting, it made things less clear and harder to follow with no additional upside.

[pothibo]

In the context of your example, your implementation is the best, hands down.

My fork had two objectives. The first was to nail the argument of "What do I do if my model has 1.2k LOC". Look at it as an extension of your solution.

The second was to show that before using Policy, there is mechanism in rails that you can use to extract bit of code away from the model (concerns, validators, etc.)

So yeah, you could say this was a future coding for possibly-if moons are aligned- extension points ;)

To reiterate, I start with in-model validation 100% of the time and move from there as needs be.

[darrencauthon]

I don't think your model has to have 1200 lines of code to see the benefits. DHH's ticket class stars with 2 lines of model code, which is a very rare case in the Rails applications I've seen. Counting by hand, I see DHH's example has one, two, three...

Twenty-six (26) lines of model code that are dedicated to validating this specific "confirmation" validation.

Given that validation is just one of the concerns of models built with The Rails Way, imagine sprinkling all of the other code that a model will have in-and-around these 26 lines of code. The central purpose of those 26 lines of code vanish into the fog of the rest of the model, creating the mystical behaviors that are common in some Rails applications.

I totally understand the concern about preemptive architecture, but once the code count for a given behavior creeps from 4, to 8, to 12... it's time to organize it into some sort of central place that's isolated from the rest. I mean, gosh, we know how this works in the real world, right?

Dev A: Here's my 26 lines of validation code to the model, DHH says it's the right thing to do.

Dev B (hours later): I need to add a little bit of behavior here, but I'm only adding a little bit of code. I'm not going to try to deduce what all of that code does, so I'll just tack mine on the bottom.

Dev C (days later): I have to add a bit of code... hmm... this is sort of a mess, I see mostly validation code but I also see some behavior. I'm not touching any of it. I'll just patch my stuff here... and here!

[iterate over and over, you get a mess of a Rails app]

I've seen this happen to multiple Rails applications... Rails applications built by experienced developers who know Rails in-and-out.

Plopping a bunch of code in something as important as a Rails model and leaving the cleanup for the next dev isn't very polite.