How I've been developing an administrative backend with ActiveAdmin

After a little time away from heavy Ruby development, I’ve been working again on a couple of projects these past few weeks. One of those projects is basically a start-over from something I’d worked on a bit over the summer—it unfortunately went down a path none of us were happy with, so the best thing to do was to start from scratch. Anyway, it’s coming together much better the second time around, I think, and a big part of that success can be attributed to ActiveAdmin.

Like RailsAdmin (covered here last December), ActiveAdmin is a gem that gives you a very good-looking backend panel for your application. It’s like Django’s automatic admin interface, but for Rails. I’m not going to provide a primer—there’s already a good one on Railscasts —but I do want to share a handful of tips based on my experiences with ActiveAdmin to date. I’m still exploring what’s possible with this gem—if you’ve found nice ways to use it, please share them in the comments and I’ll add them to this list.

Application design

Since I’m focused on rebuilding my data models and providing an interface for site managers to work with information from the database, I’ve only used ActiveAdmin’s interface to date. No other controllers, no scaffolds, just ActiveRecord models hooked to ActiveAdmin. Once I get to the controllers, I only have to worry about how they’ll look to the general public—no conditional extra administration links embedded in my views (which was becoming a problem in both excessive view logic and, frankly, in a cluttered UI). All administration will be handled through ActiveAdmin.

In addition, I’m leveraging ActiveAdmin’s dependence on Devise for authentication. I’m not crazy about Devise these days, but in this case I can use it to my advantage. Using ActiveAdmin’s default AdminUser model for administrators and, eventually, a User model for everyone else, frees me up from some authorization logic.

Users

Speaking of users, here are my customizations for ActiveAdmin’s handling of my AdminUser model. It essentially lets administrators create and manage the accounts of other administrators.

  ActiveAdmin.register AdminUser do
    form do |f|
      f.inputs 'Administrator' do
        f.input :email
        f.input :password
        f.input :password_confirmation
      end
      f.buttons
    end

    index do
      column :email
      column :last_sign_in_at
      column :last_sign_in_ip
      default_actions
    end
  end

Attachments

My app uses Paperclip for file uploads. To make this work in ActiveAdmin, I had to customize my form as follows to make image a file upload field. Note the multiple multipart requirements.

  ActiveAdmin.register Product do
    form :html => { :enctype => "multipart/form-data" } do |f|
      f.inputs "Product", :multipart => true do
        f.input :name
        f.input :description
        f.input :category
        f.input :image
        f.input :released_on
      end
      f.buttons
    end

Nested attributes

Nested attributes are among my favorite features in Rails. They can sometimes be cumbersome to set up in regular views, but this is not the case with ActiveAdmin. Here’s an implementation building upon the Product administrative panel I began customizing in the previous example.

  ActiveAdmin.register Product do
    form :html => { :enctype => "multipart/form-data" } do |f|
      f.inputs "Product", :multipart => true do
        f.input :name
        f.input :description
        f.input :category
        f.input :image
        f.input :released_on
      end
      f.has_many :prices do |p|
        p.input :price
        p.input :min_qty
      end
      f.buttons
    end
  end

Next steps

I haven’t set up ActiveAdmin’s dashboard yet, and I still have several models to implement in my new take on this application. Once those are in place, though, I can be comfortable knowing my client has a solid administrative interface to begin entering his product information and not have to wait for the public-facing parts of the site to be done. Like I said, I’m very pleased with ActiveAdmin so far and look forward to using it in future projects as well.

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