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.
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.
You can override the model's to_param method with
has_permalink :title, :param => true
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.
Originally extracted from Mephisto by technoweenie.
Conditions added by Pat Nakajima.
Henrik Nyh replaced iconv with ActiveSupport::Multibyte.