Rails slugs in URL - using record title instead of ID

Question

I've been trying to make my rails create URLs to show records by using their title instead of their ID in URL such as:

/posts/a-post-about-rockets

Following a tutorial online I did the following:

---

Because the ID is no longer in the URL, we have to change the code a bit.

class Post < ActiveRecord::Base
  before_create :create_slug

  def to_param
    slug
  end

  def create_slug
    self.slug = self.title.parameterize
  end
end

When a post is created, the URL friendly version of the title is stored in the database, in the slug column. We also have to update the finds to find records using the slug column instead of using the ID.

class ProjectsController < ApplicationController
  def show
    @project = Project.find_by_slug!(params[:id])
  end
end

---

At this point, it seems to work except showing a record, because find_by_slug! doesnt exist yet. I'm an extreme newb - where should I be defining it?

Answer 1

find_by_foo is not something that you need to define. ActiveRecord will take of it for you, as long as you have a column named "foo". Adding an exclamation point like you did will cause an exception to be thrown if no record is found, as opposed to returning nil without the exception if you don't use the exclamation point.

As for your specific issue, you added your slug to Post, but you're trying to search on Project.

Answer 2

This isn't necessarily a direct answer to your question, but have you looked at the Stringex plugin (http://github.com/rsl/stringex)? It's a great way to auto-create slugs for your records.

You can just add something like the following to your model:

class Post < ActiveRecord::Base
  acts_as_url :title
end

and it will auto-create slugs from your title and save it to the slug column.

It's also really smart about the way it creates slugs. For example, a title of "10% off, today only" gets turned into "10-percent-off-today-only".

Pretty slick!