You're so vain, you probably think this URL is about you.

Aug 08, 2014 on Rails Ruby ActiveRecord Prettyurls

In Ruby on Rails, when you want to make a particular route that has a parameter with spaces in it, you would typically get something like /regions/new%20york for a region named new york. This however looks terrible and your users would be very upset about typing this out. Fortunately, there is a way to remedy this by creating a URL slug.

First add a column called slug to the table of the resource you want to fix.

rails generate migration AddSlugToRegion slug

This creates the migration that you MUST edit before running rake db:migrate.

The preferred way is to copy and parameterize the name column of each entry after the column is created.

class AddSlugToRegion < ActiveRecord::Migration
  class Region < ActiveRecord::Base
  end

  def change
    add_column :regions, :slug, :string, index: true

    Region.all.each do |region|
      region.slug = region.name.parameterize
      region.save
    end
  end
end

You don't have to open up the Region model as you are just adding to a new column and you shouldn't have any validations affecting it, but it can be a good habit to use. Then, you are adding a column called slug which is a string and is indexed. Lastly, you are iterating through each row and changing the column to the parameterized name.

You must also edit the corresponding model.

class Region < ActiveRecord::Base
  validates :name, uniqueness: true, presence: true
  after_create :generate_slug
  before_update :assign_slug

  def to_param
    slug
  end

  private

  def assign_slug
    self.slug = to_slug
  end

  def generate_slug
    update_attributes(slug: to_slug)
  end

  def to_slug
    name.parameterize
  end
end

This seems like a lot to add, but what is happening, during record creation, is it is updating the slug after the record is created. For updating, it must be before the record is saved because it would already have a url assigned to it.

The controller must also be edited.

class RegionsController < ApplicationController
  ...
  def show
    @region = Region.find_by(slug: params[:id])
  end
  ...
end

Here it is finding the region by its slug value. So the slug value new-york would be equal to the record that has new york in the name field. Now you know how to combine this post to use the to_param method with the current post to really generate nice routes with any number of named records. I should note, make sure you validate that the name would not equal a path you would use, like new or edit. Look for more dynamic routes in a future post.

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