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Tandem is a content management system (CMS) for Rails 3.1+. We felt like it was needed because too many of the CMS options for Rails are either unpolished—something we wouldn’t want to put in front of our clients or bloated and heavy, causing many headaches when trying to integrate into existing applications.

Tandem was designed to be as simple as can be to integrate into a larger application. It’s a mountable engine that allows you to easily specify how it fits into a larger application and doesn’t bring any opinions about how that application is architected.

The simplicity doesn’t stop there, though. It also has the end user in mind. Through in-place editing, users simply navigate their site like they normally would. If they want to edit something, they simply click on it, edit it, and go on their merry way.

It’s early in the life of Tandem and we have lots in store, but it’s something we find useful and hope you will too.

Has it ever been easier to check off that “CMS functionality” feature story?

This assumes you have a rails app already. If you don’t, rails new tandem_app

1. Add the tandem gem to your Gemfile

   gem 'tandem'
   

2. Install the gem

   bundle install
   

3. Generate the tandem files

   rails g tandem
   

4. Migrate

   rake db:migrate
   

5. Start your app and you’re ready to go.

   rails s
   

Upgrade just like you would any other engine.

1. Update the gem version to the latest version in your gemfile if you specify a version.

   gem 'tandem', '~> 0.2'
   

2. Install the updated gem

   bundle update tandem
   

3. Copy any new migrations from tandem

   rake tandem:install:migrations

4. Migrate

   rake db:migrate
   

5. Enjoy the new tandem goodness.

   rails s
   

By default, Tandem uses your application layout and Tandem’s pages/show template to render pages. Both of these can be customized for an individual page.

With Tandem, you can easily insert editable content into your page by using the simple helpers, tandem_text_tag and tandem_image_tag.

Simply insert those into your templates where you want the user to be able to edit content and Tandem will take care of the rest.

<div id="sidebar">
  <%= tandem_image_tag(:sidebar_image)
  <%= tandem_text_tag(:sidebar_text)
</div>

The tandem_text_tag defaults to a basic text area. If you’d like to offer a WYSIWYG editor, you can set the editor option to :wysiwyg:

<%= tandem_text_tag(:sidebar_text, editor: :wysiwyg) %>

Tandem comes with a helper method to add a navigation menu. It’s not included in the default views, since it will most likely be used in your app’s application layout. Adding it is easy, though.

<%= tandem_navigation_tag(@page) %>

By default, Tandem will produce a nested tree of all your pages. If you just want the top level:

<%= tandem_navigation_tag(@page, Tandem::Page.top_level) %>

If you want to show just the subnavication for a given page:

<%= tandem_navigation_tag(@page, @page.children) %>

You can also create submenus easily by passing in a custom collection of pages, e.g.

<%= tandem_navigation_tag(@page, Tandem::Page.find_by_title('Services').children) %>

Now, most apps don’t simply want to let anyone edit content. Tandem allows you to easily specify how it should control access.

Inside config/initializers/tandem.rb, you can define procs for Tandem to use for authentication and authorization.

1. Tell Tandem how to find the current_user

   Tandem::Configuration.current_user_proc { |request|
     User.find(request.session['user_id']) unless request.session['user_id'].blank?
   }
   

2. Define what each user can do using CanCan

   Tandem::Configuration.user_abilities_proc { |user|
     user ||= User.new # guest user (not logged in)
   
     if user.admin?
       can :manage, :all
     else
       can :read, :all
     end
   }
   

Tandem uses paperclip for file uploads. If your application needs to modify its settings, simply set the Tandem::Configuration.paperclip_options in /config/initializers/tandem.rb

For example, to store images on S3, add the aws-sdk gem to your Gemfile and set paperclip_options to:

Tandem::Configuration.paperclip_options = { :styles => { :thumb => "150x150>" },
                                            :storage => :s3,
                                            :bucket => Proc.new { Rails.application.engine_name.gsub(/application$/, Rails.env) },
                                            :s3_credentials => {
                                                                 :access_key_id => ENV['S3_KEY'],
                                                                 :secret_access_key => ENV['S3_SECRET']
                                            } }

By default, Tandem mounts to the root of your application. We’re not trying to be pushy, it’s just what we find ourselves doing 90% of the time. To change this, simply modify your config/routes.rb to something like:

mount Tandem::Engine => "/tandem"

To change the url that you wish to serve unauthorized access errors supply a value to:

Tandem::Configuration.unauthorized_path

By default, the tandem generator copies all tandem layouts to app/views/layouts/tandem. If you wish to move your layouts to another location, supply a value to:

Tandem::Configuration.layouts_dir

By default, the uploaded images directly in the asset pipeline at :rails_root/public. To change this location, supply a value to:

Tandem::Configuration.uploaded_images_dir

By default, the uploaded images are stored and accessed via the default “paperclip” conventions (see paperclip gem). To change this behavior, supply a value to:

Tandem::Configuration.uploaded_images_template

Every new Tandem default page created has pre-defined classes setup to use either Bootstrap or 960.gs.

Here’s a preview of what the html looks like:

.container_12.row.clearfix
  p#notice = notice
  .grid_12.span12
    = tandem_image_tag(@page, :default_image)
  .grid_7.span7
    = tandem_text_tag(@page, :tandem_text_block)
  .grid_5.span5
    = tandem_text_tag(@page, :tandem_sidebar)

If either of those grid systems are being used those styles will pull in accordingly.

Tandem realized that even the most basic site will often have pages that should be represented as resources with basic CRUD functionality, e.g. people, events, FAQs, etc. Tandem, therefore, comes with a generator that allows you to create a Tandem resource that provides all of that functionality wrapped in the same Tandem interface your users are used to using for editing other content in the application.

To generate a tandem resource, simply call the tandem_resource generator:

rails generate tandem:resource Faq question:string answer:string position:integer

1. Fork it.

2. Create a branch (git checkout -b my_markup)

3. Commit your changes (git commit -am “Added Snarkdown”)

4. Push to the branch (git push origin my_markup)

5. Open a Pull Request

We are big believers in testing, so every pull request needs to be tested.

1. Run Bundle

   bundle install
   

2. Create the Database

   rake db:create
   

3. Run the Migrations

   rake db:migrate
   

4. Prepare the Test Database

   rake app:db:test:prepare

5. See all the Green.

   rake
   

Tandem is released under the MIT license:

• www.opensource.org/licenses/MIT