IMPORTANT: If you are upgrading to Mongoid Slug 1.0.0 please migrate in accordance with the instructions in https://github.com/digitalplaywright/mongoid-slug/wiki/How-to-upgrade-to-1.0.0-or-newer. Mongoid Slug 1.0.0 stores the slugs in a single field _slugs of array type, and all previous slugs must be migrated.

Mongoid Slug

Mongoid Slug generates a URL slug or permalink based on one or more fields in a Mongoid model. It sits idly on top of [stringex] 1, supporting non-Latin characters.

Installation

Add to your Gemfile:

gem 'mongoid_slug'

Usage

Set up a slug:

class Book
  include Mongoid::Document
  include Mongoid::Slug

  field :title
  slug :title
end

Find a document by its slug:

# GET /books/a-thousand-plateaus
book = Book.find params[:book_id]

Mongoid Slug will attempt to determine whether you want to find using the slugs field or the _id field by inspecting the supplied parameters.

• Mongoid Slug will perform a find based on slugs only if all arguments passed to find are of the type String
• If your document uses BSON::ObjectId identifiers, and all arguments look like valid BSON::ObjectId, then Mongoid Slug will perform a find based on _id.
• If your document uses any other type of identifiers, and all arguments passed to find are of the same type, then Mongoid Slug will perform a find based on _id.
• If your document uses String identifiers and you want to be able find by slugs or ids, to get the correct behaviour, you should add a slug_id_strategy option to your _id field definition. This option should return something that responds to call (a callable) and takes one string argument, e.g. a lambda. This callable must return true if the string looks like one of your ids.

Book.fields['_id'].type
=> String
book = Book.find 'a-thousand-plateaus' # Finds by slugs
=> ...

class Post
  include Mongoid::Document
  include Mongoid::Slug

  field :_id, type: String, slug_id_strategy: lambda {|id| id.start_with?('....')}

  field :name
  slug  :name, :history => true
end

Post.fields['_id'].type
=> String
post = Post.find 'a-thousand-plateaus' # Finds by slugs
=> ...
post = Post.find '50b1386a0482939864000001' # Finds by bson ids
=> ...

[Read here] 4 for all available options.

Custom Slug Generation

By default Mongoid Slug generates slugs with stringex. If this is not desired you can define your own slug generator like this:

class Caption
  include Mongoid::Document
  include Mongoid::Slug

  #create a block that takes the current object as an argument
  #and returns the slug.
  slug do |cur_object|
    cur_object.slug_builder.to_url
  end
end

You can call stringex to_url method.

Scoping

To scope a slug by a reference association, pass :scope:

class Company
  include Mongoid::Document
  
  references_many :employees
end

class Employee
  include Mongoid::Document
  include Mongoid::Slug
  
  field :name
  referenced_in :company
  
  slug  :name, :scope => :company
end

In this example, if you create an employee without associating it with any company, the scope will fall back to the root employees collection.

Currently, if you have an irregular association name, you must specify the :inverse_of option on the other side of the assocation.

Embedded objects are automatically scoped by their parent.

The value of :scope can alternatively be a field within the model itself:

class Employee
  include Mongoid::Document
  include Mongoid::Slug
  
  field :name
  field :company_id
  
  slug  :name, :scope => :company_id
end

History

To specify that the history of a document should be kept track of, pass :history with a value of true.

class Page
  include Mongoid::Document
  include Mongoid::Slug
  
  field :title
  
  slug :title, history: true
end

The document will then be returned for any of the saved slugs:

page = Page.new title: "Home"
page.save
page.update_attributes title: "Welcome"

Page.find("welcome") == Page.find("home") #=> true

Reserved Slugs

Pass words you do not want to be slugged using the reserve option:

class Friend
  include Mongoid::Document

  field :name
  slug :name, reserve: ['admin', 'root']
end

friend = Friend.create name: 'admin'
Friend.find('admin') # => nil
friend.slug # => 'admin-1'

Custom Find Strategies

By default find will search for the document by the id field if the provided id looks like a BSON ObjectId, and it will otherwise find by the _slugs field. However, custom strategies can ovveride the default behavior, like e.g:

module Mongoid::Slug::UuidIdStrategy
  def self.call id
    id =~ /\A([0-9a-fA-F]){8}-(([0-9a-fA-F]){4}-){3}([0-9a-fA-F]){12}\z/
  end
end

Use a custom strategy by adding the slug_id_strategy annotation to the _id field:

class Entity
  include Mongoid::Document
  include Mongoid::Slug

  field :_id, type: String, slug_id_strategy: UuidIdStrategy

  field :user_edited_variation
  slug  :user_edited_variation, :history => true
end

Adhoc checking whether a string is unique on a per Model basis

Lets say you want to have a auto-suggest function on your GUI that could provide a preview of what the url or slug could be before the form to create the record was submitted.

You can use the UniqueSlug class in your server side code to do this, e.g.

title = params[:title]
unique = Mongoid::Slug::UniqueSlug.new(Book.new).find_unique(title)
...
# return some representation of unique