param

In Rails, you can define a to_param method on any ActiveRecord model:

class Order < ActiveRecord::Base
  def to_param
    number
  end
end

Now, the order’s number is used instead of its id when a route is generated:

order = Order.create(number: 'R1234')
order_path(order) #=> '/orders/R1234'

However, you’re still left to look up the order by its number manually:

class OrdersController < ApplicationController
  def show
    @order = Order.find_by(number: params[:id])
  end
end

This library adds a from_param method to your model classes to do this lookup automatically:

Order.from_param(params[:id])

Add this line to your application's Gemfile:

gem 'param', '~> 0.1'

And then execute:

$ bundle

Or install it yourself as:

$ gem install param

Use the param DSL on any ActiveRecord model to specify the name of the param attribute:

class Order < ActiveRecord::Base
  param :number
end

Pass the to_s option if you want the param to also be used as the model’s to_s method:

class Order < ActiveRecord::Base
  param :number, to_s: true
end

After checking out the repo, run bin/setup to install dependencies. Then, run rake to run the tests. You can also run bin/console for an interactive prompt that will allow you to experiment.

Bug reports and pull requests are welcome. This project is intended to be a safe, welcoming space for collaboration, and contributors are expected to adhere to the Contributor Covenant code of conduct.

The gem is available as open source under the terms of the MIT License.