Multistep form wizard from scratch in Rails

This (Rails 5) project demonstrates how to break up a model-backed form into multiple steps without any gems. This kind of thing can get pretty complex, but this implementation is fairly straightforward, flexible, and reusable. It can work with Rails 3-4 as well.

Background

This railscast is a solid approach that I used as a starting point. But there are a few problems with it that my project attempts to solve:

• Browser back/forward buttons shouldn't break it.
• Clicking "back" through the steps shouldn't validate the current step (maybe a personal preference?).
• Support for edit/update existing record.
• Keep the code out of the controller.
• Abstract the approach for any model.

Installing

git clone git://github.com/nerdcave/rails-multistep-form.git
cd rails-multistep-form
bundle install
rake db:migrate
rake db:test:prepare
rails s

Run rspec to run the tests, and/or visit http://localhost:3000/products.

If you have any issues, be sure you're using Ruby >= 2.3.

Implementation details

• To validate an attribute, all that's needed is a conditional with the step to enforce validation:

validates :name, presence: true, if: :step1?
validates :quantity, numericality: true, if: :step2?

• If you create/update an object without the multistep form (i.e. in a test or the rails console), the step logic will be ignored and all fields will validate as expected.

Using in your own project

• Copy these files: app/models/concerns/multi_step_model.rb and app/services/model_wizard.rb.
• In your model, include MultiStepModel and define self.total_steps.
• Then just follow the conventions in this project that uses them. Check out the ProductsController, in particular, and the view form.

Features

• Multi or single step create/update.
• Not much code and abstracted to handle most models.
• Validate attributes per step with stepX? methods.
• RSpec/Capybara feature tests included.
• Browser back/forward should work as expected (Turbolinks not supported).

Limitations

While this works for most simple models, it's not flawless. Here are a few issues:

• Browser back/forward buttons break if using Turbolinks.
• Nested models may have issues (broken test case included).
• Complicated fields such as uploads may be a problem.