non-active-record-resource.md

Yes, it is possible to create a custom form in Active Admin without using an ActiveRecord database model. Active Admin is built on top of the Rails framework, and while it is primarily designed to work with ActiveRecord models, you can still create custom forms and interact with non-ActiveRecord models or even external APIs.

Here’s how you can achieve this:

Steps to Create a Custom Form in Active Admin Without ActiveRecord:

Define a Plain Ruby Class (Model): Create a plain Ruby class that represents your custom model. This class does not need to inherit from ActiveRecord::Base. You can use ActiveModel::Model to include basic model behavior like validations and form handling.

# app/models/custom_model.rb
class CustomModel
  include ActiveModel::Model

  attr_accessor :name, :email, :message

  validates :name, presence: true
  validates :email, presence: true, format: { with: URI::MailTo::EMAIL_REGEXP }
end

Create a Custom Form in Active Admin: In your Active Admin resource file, define a custom form using the form block. You can use the form_for method to create a form for your custom model.

# app/admin/custom_forms.rb
ActiveAdmin.register_page "Custom Form" do
  content do
    render partial: 'admin/custom_forms/form'
  end

  page_action :submit, method: :post do
    @custom_model = CustomModel.new(custom_model_params)

    if @custom_model.valid?
      # Handle the valid data (e.g., send an email, call an API, etc.)
      redirect_to admin_custom_form_path, notice: "Form submitted successfully!"
    else
      render :form
    end
  end

  controller do
    def custom_model_params
      params.require(:custom_model).permit(:name, :email, :message)
    end
  end
end

Create a Partial for the Form: Create a partial view for the form. This will be rendered in the Active Admin page.

# app/views/admin/custom_forms/_form.html.erb
<%= form_for @custom_model || CustomModel.new, url: admin_custom_form_submit_path, method: :post do |f| %>
  <% if @custom_model&.errors&.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@custom_model.errors.count, "error") %> prohibited this form from being saved:</h2>
      <ul>
        <% @custom_model.errors.full_messages.each do |message| %>
          <li><%= message %></li>
        <% end %>
      </ul>
    </div>
  <% end %>

  <div class="field">
    <%= f.label :name %>
    <%= f.text_field :name %>
  </div>

  <div class="field">
    <%= f.label :email %>
    <%= f.email_field :email %>
  </div>

  <div class="field">
    <%= f.label :message %>
    <%= f.text_area :message %>
  </div>

  <div class="actions">
    <%= f.submit "Submit" %>
  </div>
<% end %>

Add a Route for the Custom Form: Add a route for the custom form and its submission action in your config/routes.rb file.

# config/routes.rb
namespace :admin do
  get 'custom_form', to: 'custom_forms#index'
  post 'custom_form/submit', to: 'custom_forms#submit', as: 'custom_form_submit'
end

Handle Form Submission: In the page_action :submit block, you can handle the form submission. For example, you might send an email, call an external API, or process the data in some other way.

Key Points:

No Database Required: Since you’re using a plain Ruby class, there’s no need for a database table.
Validations: You can still use ActiveModel validations to ensure data integrity.
Flexibility: You can use this approach to interact with external APIs or services instead of a database.

This approach allows you to leverage Active Admin’s interface while working with non-ActiveRecord models or custom logic.

philiplambok/non-active-record-resource.md

Steps to Create a Custom Form in Active Admin Without ActiveRecord:

Key Points: