How do you handle serialized edit fields in an Active Admin resource? - ruby

Question

I have a model, Domain, which has a text field, names.
> rails g model Domain names:text
invoke active_record
create db/migrate/20111117233221_create_domains.rb
create app/models/domain.rb
> rake db:migrate
== CreateDomains: migrating ==================================================
-- create_table(:domains)
-> 0.0015s
== CreateDomains: migrated (0.0066s) =========================================
I set this field as serialized into an array in the model.
# app/models/domain.rb
class Domain < ActiveRecord::Base
serialize :names, Array
end
Create the ActiveAdmin resource for this model
> rails g active_admin:resource Domain
create app/admin/domains.rb
then, in the app/admin/domains.rb, I setup the various blocks to handle the serialized field as such
# app/admin/domains.rb
ActiveAdmin.register Domain do
index do
id_column
column :names do |domain|
"#{domain.names.join( ", " ) unless domain.names.nil?}"
end
default_actions
end
show do |domain|
attributes_table do
row :names do
"#{domain.names.join( ", " ) unless domain.names.nil?}"
end
end
end
form do |f|
f.inputs "Domain" do
f.input :names
end
f.buttons
end
# before we save, take the param[:domain][:name] parameter,
# split and save it to our array
before_save do |domain|
domain.names = params[:domain][:names].split(",") unless params[:domain].nil? or params[:domain][:names].nil?
end
end
Nearly everything works great -- my names are displayed as comma separated in the index and show views. When I update a record with my names field set to "a,b,c", the before_save works to turn that into an array that is then saved via the ActiveRecord serialize.
What I can not solve is how to make the edit form put in a comma-separated list into the text field. I tried using a partial and using formtastic syntax directly as well as trying to make it work via the active_admin DLS syntax. Does anyone know how to make this work?
Specifically, if I have the following array saved in my domain.names field:
# array of names saved in the domain active_record
domain.names = ["a", "b", "c"]
how to change:
form do |f|
f.inputs "Domain" do
f.input :names
end
f.buttons
end
so that when the edit form is loaded, in the text field instead of seeing abc, you see a,b,c.

Answer 1

Here is a summary of how I handled this situation. I added an accessor to the model which can turn the Array into a string joined by a linefeed and split it back to an Array.
# app/models/domain.rb
class Domain < ActiveRecord::Base
serialize :names, Array
attr_accessor :names_raw
def names_raw
self.names.join("\n") unless self.names.nil?
end
def names_raw=(values)
self.names = []
self.names=values.split("\n")
end
end
then, in my admin resource for domain, instead of using the :names field, I used the :names_raw field. setting this value would save the names Array with the new values.
# app/admin/domains.rb
form do |f|
f.inputs "Domain" do
f.input :names_raw, :as => :text
end
f.buttons
end

Answer 2

Stumbled on this question looking for something to have access to a serialized Hash's YAML. I used this solution on Rails 3.2:
def target_raw
#attributes['target'].serialized_value
end
def target_raw=(new_value)
#attributes['target'].state = :serialized
#attributes['target'].value = new_value
end