PermalinkFu

A simple plugin for creating URL-friendly permalinks (slugs) from attributes.

Uses ActiveSupport::Multibyte::Handlers::UTF8Handler (part of Rails since 1.2) rather than iconv (which is inconsistent between platforms) for normalization/decomposition.

Usage

class Article < ActiveRecord::Base
  has_permalink :title
end

This will escape the title in a before_validation callback, turning e.g. "Föö!! Bàr" into "foo-bar".

The permalink is by default stored in the permalink attribute.

has_permalink :title, :as => :slug

will store it in slug instead.

has_permalink [:category, :title]

will store a permalink form of "#{category}-#{title}".

Permalinks are guaranteed unique: "foo-bar-2", "foo-bar-3" etc are used if there are conflicts. You can set the scope of the uniqueness like

has_permalink :title, :scope => :blog_id

This means that two articles with the same blog_id can not have the same permalink, but two articles with different blog_ids can.

Two finders are provided:

Article.find_by_permalink(params[:id])
Article.find_by_permalink!(params[:id])

These methods keep their name no matter what attribute is used to store the permalink.

The find_by_permalink method returns nil if there is no match; the find_by_permalink! method will raise ActiveRecord::RecordNotFound.

By default, this fork will override ActiveRecord::Base#to_param so that your controllers can still find your models without further work:

article.to_param
# => "1-foo-bar"

You can change this behavior by using the param option:

has_permalink :title, :param => :permalink

has_permalink :title, :param => false

This means that the permalink will be used instead of the primary key (id) in generated URLs. Remember to change your controller code from e.g. find to find_by_permalink!.

You can add conditions to has_permalink like so:

class Article < ActiveRecord::Base
  has_permalink :title, :if => Proc.new { |article| article.needs_permalink? }
end

Use the :if or :unless options to specify a Proc, method, or string to be called or evaluated. The permalink will only be generated if the option evaluates to true.

You can use PermalinkFu.escape to escape a string manually.

Credits

Originally extracted from Mephisto by technoweenie.

Conditions added by Pat Nakajima.

Henrik Nyh replaced iconv with ActiveSupport::Multibyte.