Add support for custom validation contexts in resource creation and update

[goosys]

• Separated from Add context to Page #2457

---

This pull request introduces support for customizable validation contexts when creating or updating resources in the Administrate controllers. This allows developers to specify different validation scenarios based on user roles or other conditions, providing more flexibility for resource validation logic. Documentation and tests have been updated to reflect and verify this new functionality.

Controller enhancements for validation contexts:

• Added validation_contexts_on_create and validation_contexts_on_update methods to Administrate::ApplicationController, allowing developers to override and specify custom validation contexts for resource creation and update. The default context is :create or :update based on whether the record is new. (app/controllers/administrate/application_controller.rb)

Documentation updates:

• Added a new section in docs/customizing_controller_actions.md.

Testing improvements:

• Added controller specs in spec/controllers/admin/application_controller_spec.rb.

---

Usage:

# Model
validates :name, presence: true, on: :save_by_regular_admin

# Controller
def validation_contexts_on_create(resource)
  if current_user.super_admin?
    super + [:save_by_super_admin]
  else
    super + [:save_by_regular_admin]
  end
end

def validation_contexts_on_update(resource)
  if current_user.super_admin?
    super + [:save_by_super_admin]
  else
    super + [:save_by_regular_admin]
  end
end

[goosys]

@pablobm
I rebased the branch and pushed the updated changes. Could you please review it again?

[pablobm]

Could this be done differently, in a more flexible way? For example, we could have a resource_save hook (or perhaps resource_save_on_create/resource_save_on_update). Then users can add these options or others like validate: false and touch: false, as well as run additional changes and checks before/after the save itself. Or even save differently (not with save). What do you think?

[goosys]

I’m working on refactoring the controllers, and I expect that the save operation itself will likely be split into methods like this in the future:

https://github.com/goosys/administrate/blob/e9aa93f5eea7d0fdebc35a95c55b87966387db40/app/controllers/concerns/administrate/resource_manager.rb#L59-L61

This would allow users to customize the save method to perform additional work before or after saving, or even to change how the resource is saved.

Since validation_context is a natural Active Record feature, I think it would still be reasonable to expose it through a dedicated hook or method, even if the save operation is later split into separate methods.

What do you think?

[pablobm]

The initial problem is probably with me: I don't think I have ever used validation contexts in the real world 😅 They sound great, but for one reason or the other I haven't ended up using them. Perhaps they are more common in the wider Rails community than they are in my own bubble, so I can entertain the option.

But then I think a bit more and remember that #save takes other options. There are valid reasons why users may want to do validation: false or touch: false and we aren't adding additional hooks for them. I think a hook specific for the resource.save (like the one you have in that other branch) is simpler, more useful, and more obvious to users. If that hook is coming up (in your separate proposal), I think it's not worth complicating it more by adding more sub-hooks that are tiny and I feel not as common.