Adding Custom Field Types

If your application deals with a nonstandard data type, you can create an Administrate::Field object to help display the custom data type across the dashboard.

Administrate::Field objects consist of two parts: a Ruby class and associated views.

For example, let's create a Field that displays Gravatars based on an email.

First, we'll run a generator to set us up with the files we need:

rails generate administrate:field gravatar

This creates a few files:

We can edit the app/fields/gravatar_field.rb to add some custom logic:

# app/fields/gravatar_field.rb
require 'digest/md5'

class GravatarField < Administrate::Field::Base
  def gravatar_url
    email_address = data.downcase
    hash = Digest::MD5.hexdigest(email_address)

Next, we can customize the partials to display data how we'd like. Open up the app/views/fields/gravatar_field/_show.html.erb partial. By default, it looks like:

<%= field.to_s %>

Since we want to display an image, we can change it to:

<%= image_tag field.gravatar_url %>

You can customize the other generated partials in the same way for custom behavior on the index and form pages.

Using your custom field

We need to tell Administrate which attributes we'd like to be displayed as a gravatar image.

Open up a dashboard file, and add the gravatar field into the ATTRIBUTE_TYPES hash. It should look something like:

class UserDashboard < Administrate::BaseDashboard
    created_at: Field::DateTime,
    updated_at: Field::DateTime,
    name: Field::String,
    email: GravatarField,    # Update this email to use your new field class
    # ...