Use slug in wishlist url

[radvc]

Resolves #156

[leesharma]

Have you heard of the ActiveRecord #to_param method? (docs) According to the documentation:

You can override to_param in your model to make user_path construct a path using the user’s name instead of the user’s id:

class User < ActiveRecord::Base
  def to_param  # overridden
    name
  end
end

user = User.find_by_name('Phusion')
user_path(user)  # => "/users/Phusion"

You can also access the param by calling @object.param, which is handy for the controller specs.

It looks like that would cut down on the number of custom methods you're using.

[radvc]

@leesharma oh, not heard about that method, thanks for that. I will edit my PR

[radvc]

@leesharma I updated my PR.

[leesharma]

Nice work! It looks like this is almost there. 😄

I made some comments below, but here's the summary:

• We need to handle the case of attempted slug duplication. Since we're using them for urls, they can't be allowed; we should handle that gracefully.
• Since the slug is used to find wishlist items, a unique index should be added to the db. It should also not be nullable.
• This change needs some unit tests: creating a wishlist should set a slug, updating a wishlist should set a slug, and attempted slug duplication should be handled reasonably.

Let me know if you have any questions/thoughts!

[leesharma]

Whitespace! 😮

[leesharma]

Let's add a unique index to this column since we search by it so often. We should probably disallow nulls too.

[leesharma]

What happens when an admin tries to add/update a valid wishlist that results in a duplicate slug? For example, "Wishlist 1" and "wishlist-1" are unique names but would result in the same slug. Since we're using them as the param, slugs must be unique.

Validations are run before the before_save callback, so a simple validation won't work. Maybe a before_validation callback or some sort of slug incrementing would work? I bet someone's solved this and written a blog post.

[leesharma]

This change is fine, but let's really test this change in the unit tests (spec/models/wishlist_spec.rb).

For the model specs, you'll want to verify that the slug gets set correctly after a save or an update. We'll also need to test how wishlist items with duplicate slugs are handled (see above). We probably don't need to test input edge cases since String#parameterize/ActiveSupport are well-tested already.

[radvc]

@leesharma what if I concat the id and the slug, 1-dc-general ?