ActiveModel::ForbiddenAttributesError when creating new user

📝 Blog Post: How to Fix ActiveModel::ForbiddenAttributesError when Creating New User

Hey there, tech enthusiasts! 👋 Are you struggling with the dreaded ActiveModel::ForbiddenAttributesError when trying to create a new user in Ruby? 😫 Don't worry, we've got you covered! In this easy-to-follow guide, we'll address this common issue, provide simple solutions, and get you up and running in no time. Let's dive in! 💻

Understanding the Problem

The ActiveModel::ForbiddenAttributesError occurs when you pass an entire params hash to the User.new method instead of specifying the specific attributes permitted for mass assignment. This error typically arises due to strong parameter restrictions. 🚫

In the given code snippet, the create action initializes a new user using User.new(params[:user]). However, this approach leads to the ForbiddenAttributesError. So, how do we fix it? Let's find out!

Solution: Strong Parameters to the Rescue

To bypass the ActiveModel::ForbiddenAttributesError, we need to implement strong parameters. 💪 Strong parameters allow you to specify which attributes are permitted for mass assignment, providing an added layer of security for your application.

Here's how you can modify the code to use strong parameters:

# Add a private method at the bottom of your controller
private
def user_params
  params.require(:user).permit(:username, :email, :password)
end

Now, let's update the create action to use the user_params method:

def create
  @user = User.new(user_params)
  # ...
end

By defining and utilizing the user_params method, we declare the permitted attributes for the user model. This ensures that only the specified attributes can be mass assigned, eliminating the ActiveModel::ForbiddenAttributesError. 🎉

Establishing a Proper User Registration Form

While we're at it, let's also discuss how to set up a foolproof user registration form. ⚙️

In your view file for the form (let's assume it's new.html.erb), make sure you're using the form_for helper and generating the appropriate form fields. For example:

<%= form_for @user do |f| %>
  <%= f.label :username %>
  <%= f.text_field :username %>

  <%= f.label :email %>
  <%= f.email_field :email %>

  <%= f.label :password %>
  <%= f.password_field :password %>

  <%= f.submit "Sign Up" %>
<% end %>

Ensure that the form fields align with your User model attributes. This way, the values entered in the form will be correctly captured by the strong parameters in the controller.

Wrapping Up

Congratulations on making it through! 🎉 You've learned how to fix the ActiveModel::ForbiddenAttributesError by implementing strong parameters. Additionally, we also covered the basics of setting up a proper user registration form.

If you found this guide helpful or have any questions, feel free to leave a comment below. Keep exploring, keep coding, and happy user creation! 🚀