The Complete N00b's Guide to Active Scaffold

If you’re new to both Rails and Active Scaffold, some things which may seem obvious to more experienced hands, can be frustratingly perplexing.

Rails is neat, but it can also be confusing for a C or Java programmer, Rails just takes care of some things that you’d otherwise be doing by hand; this can be perplexing. because you’re looking for where things are happening in the code to get practical examples, and none exist.

So what do you do?

You just try stuff and hope it works and when it doesn’t you pull your hair out.
This guide helps to overcome some of those issues. We’ll be adding to this guide as we discover little solutions to mind-blowing (for n00bs) anyway problems.

How to Make Active Scaffold work with Acts as [whatever]

The “Acts As” plug ins are awesome, ActiveScaffold is awesome. Getting them to work together, not so awesome. You can view your scaffolds but when you try to create, you get the dreaded 500 error — that had me stumped for a week. Here’s the long and short of it, you need to tell Active Scaffold what fields you’re bringing in from the Acts_As polymorphic association (because it doesn’t know otherwise). You do that like this:

# I have Acts_as_Taggable_on installed in my story module, I have created scopes
# for :destinations and :interests, if I don’t tell Active Scaffold that,
# it has a friggin stroke when we try to create records. 

active_scaffold :story do |config|
    config.columns = [:title, :by_line, :one_liner, :lede,
      :body, :custom_layout, :layout,
      :editorial_workflow_status, :content_type, :publish_date, :destinations,
      :interests]
end

Now, poof it works!

---

How to make a look up field without using a table
So this has been killing me for a week. The scenario is simple. I have a table “Stories”, which has a field “Content Type”. You know for ‘Reviews’, ‘Blogs’, or whatever. Now the easy thing to do would be to create a look up table, and active scaffold would do it’s magic behind the scenes, and we’d be good to go.

except

Look up tables whose sole purpose is to look up a single string would create a choke point at the database layer for a high performance application. So I use integers, and symbols, and all is good, right?

yeah, not to much.

The API documentation says that the following should work:

active_scaffold :story do |config|
    #do stuff like specify what fields we want so that Acts_on_[whatever] doesn’t die
      config.columns[:content_type].form_ui = :select
      config.columns[:content_type].options = {"story" => 1, 
                             "review" => 2, "story page" => 3}
end 

Of course that doesn’t work, I don’t know why. At this point I don’t really care, this does

active_scaffold :story do |config|
     #do stuff like specify what fields we want so that 
     #Acts_on_[whatever] doesn’t break on create

     config.columns[:content_type].ui_type = :select
                    # The ":update_column" symbol is to identify foregin fields  
                    # in a polymorphic association. This isn't but it could be
                    # so I figured I'd  illustrate it 
     config.columns[:content_type].options = {:update_column => :content_type, 
                               :options => [["story",  1], ["story", 2]]}
end

And don’t ask me why.