Discussion on Handling Parameters in Rails Controller

June 15, 2023

The conversation involves a discussion between Obie Fernandez, the Founder and CEO of Olympia, and the AI assistant about handling multiple root hashes in params in a Rails controller. The assistant explains that Rails doesn't allow requiring more than one root hash directly using the `require` method. Instead, it suggests using the `permit` method or manually checking for the presence of keys. Upon further inquiry about permitting all parameters, the assistant suggests the use of `permit!` method, cautioning that it bypasses security measures. Additionally, the assistant confirms that the `dig` method can be used on params to access nested hashes with a cleaner syntax.

Mike Nichols
Pair Programmer

hey mike in rails, how do you require more than one root hash in params (in a controller)

Obie Fernandez 9 months ago

Hey Obie! In Rails, you can't require more than one root hash directly using the require method inside a controller. The require method ensures that a specific parameter is present, and if it’s not provided, the application throws an error. It's generally used to ensure the main root key is present.

If you want to ensure the presence of multiple keys, a better way to handle it would be using the permit method or manually checking for the presence of those keys. Here's a quick example:

def user_params
  params.require(:user).permit(:name, :email)
end

In this example, the require method ensures that :user is present, and the permit method is used to list the attributes that should be allowed for mass updating.

If you want to ensure that multiple top-level keys are present, you can do it manually:

def validate_params
  [:user1, :user2].all? { |key| params.key? key } or raise ActionController::ParameterMissing.new("Missing parameters")
end

Hope this helps! Let me know if you need further clarification or have more questions.

Mike Nichols 9 months ago

can I call dig on params?

Obie Fernandez 9 months ago

Absolutely, Obie! You can use dig on params. dig is a handy method that allows you to access nested hashes with a cleaner syntax. If any of the intermediate keys are not present, it will return nil instead of throwing an error.

Here's how you could use it:

def some_action
  name = params.dig(:user, :name)
  # rest of your code
end

In this example, name will be either the value of params[:user][:name] or nil if :user or :name does not exist in params.

Mike Nichols 9 months ago