Fun with the simple_form Rails Gem

It’s been a long time since I sat down to write a blog about a programming related topic. I’m really hoping that changes this year, but I’ll do my best not to make promises I can’t be sure I’ll keep. I definitely hope to share more of the things I’m learning about and playing with. With that in mind, I was playing with the simple_form gem earlier today and I thought I would share the experiment that I was working on.

Often when working on a project I’ll have a few basic forms that I need for data entry within the system. Nothing too complex, just a few simple fields. For those of you who haven’t checked out simple_form yet, I highly recommend it. After getting the gem installed I created the form I needed:

<%= simple_form_for @member do |f| %>
  <%= f.input :firstname %>
  <%= f.input :lastname %>
  <%= f.input :email %>
  <%= f.input :bio %>
  <%= f.button :submit %>
<% end %>

Knowing that I would need a few more simple forms I wanted to figure out a way to be able to reuse this code snippet. Although I might not do this same approach in a large project with more complex forms I proceeded to pull out the column symbols within the snippet and came up with this:

<%= simple_form_for @member do |f| %>
  <% @member.class.column_names.each do |field| %>
    <%= f.input field.to_sym unless %w{id created_at updated_at}.include?(field) %>
  <% end %>
  <%= f.submit %>
<% end %>

This takes the @member instance variable and get its class, which in this case is Member. It looks at the column names of Member and loops through them. If the field isn’t “id”, “created_at”, or “updated_at” it creates an input field for it. This was a step closer to what I was going for. I imagine there are many opinions about this approach especially when it comes to thoughts on performance. The focus here was about experimentation. So I keep going and made some additional adjustments, caming up with this:

<%= simple_form_for form do |f| %>
  <% form.class.column_names.each do |field| %>
    <%= f.input field.to_sym unless %w{id created_at updated_at}.include?(field) %>
  <% end %>
  <%= f.submit %>
<% end %>

This allowed me to call the code as a partial like:

<%= render :partial => 'shared/form', :object => @member %>

It’s not perfect, I can’t customize the fields in any way, but it let’s me get some basic forms quickly together for testing concepts with a customer.

Anyway, that’s my recent experiment, feel free to share your thoughts and feedback.


Magic-Ruby 2011 Conference Talks

I was lucky enough to be able to spend the last few days with some amazing Ruby developers. I enjoyed meeting so many new people and getting the chance to learn about some seriously awesome projects that they are working on. In an effort to consolidate some of the slides and information shared by the speakers I’ve created this post. If you have any updates please leave them in the comments and I’ll continue to complete the list.


  • Cultivating Cucumber: Slides
    Les Hill, Hashrocket
  • Geospacing Your Ruby: Slides and Video of similar talk from July 9, 2010
    Peter Jackson, Intridea
  • Loving your customers, loving your peers
    Alan Johnson, Carsonified
  • Code Isn’t Enough
    Gregg Pollack / Caike Souza
  • Exceptional Ruby: Slides, Code, and Review | Video
    Avdi Grimm
  • What Happened to Desktop Development in Ruby
    Andy Maleh, Obtiva
  • Keynote
    Dave Thomas, Pragmatic Programmers


  • Meditation + Code: Slides
    Mike Gehard, Pivotal Labs
  • Crank Up Your Apps with TorqueBox: Slides | Video
    Jim Crossley, Red Hat
  • How I Learned to Stop Worrying and Love the Cloud: Slides
    Wesley Beary, Engine Yard
  • Developing Cocoa Applications with MacRuby: Slides
    Brendan Lim, Intridea
  • Documentation is freaking awesome: Slides and Links
    Kyle Neath, Github
  • Lightning Talks: Videos
  • Keynote – McDonalds, Six Sigma, and Offshore Outsourcing: Notes
    Chad Fowler, InfoEther

A special thanks to all the speakers and Jeremy McAnally for putting it all together. Anyone wishing to stay in touch can find me on Twitter @timknight.