Fan-Gated Facebook Tab with Rails 3 - ruby-on-rails-3

Question

I followed a how to by CoverHound see
How to Create a Fan-gated Facebook Tab with Rails and JavaScript.
Everything went smooth up until step 3 under Serve the content for your FB App with a Rails application When previewing using my local server, I got an error. Typical rails security issue, simply solved by adding
protect_from_forgery :except => :index
to my FacebookController. From there I was golden, tested it on my live site and work swimmingly. Now to add the Gate!
Added the if statement to my facebook index.html.erb file
<% if user_likes_page? %>
<div class="fans_tickets"></div>
<% else %>
<div class="like_tickets"></div>
<% end %>
In the FacebookHelper I added the following to test for the like, and to parse the signed_request from Facebook
def user_likes_page?
fb_request = parse_signed_request
return fb_request['page']['liked'] if fb_request && fb_request['page']
end
def parse_signed_request
if params[:signed_request].present?
sig, payload = params[:signed_request].split('.')
payload += '=' * (4 - payload.length.modulo(4))
data = Base64.decode64(payload.tr('-_','+/'))
JSON.parse( data )
end
rescue Exception => e
Rails.logger.warn "!!! Error parsing signed_request"
Rails.logger.warn e.message
end
When tested on my localhost, It works great, if I haven't liked the page, I see the div with the info telling me to like the page for the contest info, when I have liked the page it shows me the info about the contests mentioned on the non-fan div. Great!
Post it to the Live server and I get an error page that shows up. In my Logs I see this...
2011-09-23 12:38:29 INFO -- Processing by FacebookController#index as HTML
2011-09-23 12:38:29 INFO -- Parameters: {"signed_request"=>"-IIMtqxxUICCyfCOxpsBMvApiaLgEZAkr1tQltvK_bI.eyJhbGdvcml0aG0iOiJITUFDLVNIQTI1NiIsImlzc3VlZF9hdCI6MTMxNjgwMzEwNywicGFnZSI6eyJpZCI6IjEzNzg2NDQ2NjMxMDQwOSIsImxpa2VkIjp0cnVlLCJhZG1pbiI6dHJ1ZX0sInVzZXIiOnsiY291bnRyeSI6ImNhIiwibG9jYWxlIjoiZW5fVVMiLCJhZ2UiOnsibWluIjoyMX19fQ"}
2011-09-23 12:38:29 WARN -- !!! Error parsing signed_request
2011-09-23 12:38:29 WARN -- undefined method `encoding' for #<String:0x7f845221da58>
2011-09-23 12:38:29 INFO -- Rendered facebook/index.html.erb within /layouts/facebook (37.4ms)
2011-09-23 12:38:29 INFO -- Completed in 77ms
2011-09-23 12:38:29 FATAL --
ActionView::Template::Error (undefined method `[]' for true:TrueClass):
1: <% if user_likes_page? %>
2: <div class="fans_flames_tickets"></div>
3: <% else %>
4: <div class="like_flames_tickets"></div>
app/helpers/facebook_helper.rb:4:in `user_likes_page?'
app/views/facebook/index.html.erb:1:in `_app_views_facebook_index_html_erb___1213205873_70103145189880_0'
app/controllers/facebook_controller.rb:6:in `index'
I can't seem to figure out what would be causing this, the code doesn't look to be relying on anything from the actual server itself... Any help would be appreciated!
oh and I didn't continue on with the "How do I get the Facebook userID of the visitor viewing my fan page?" as I don't require it, its just for the like information.
UPDATE
Figured it out with debugging... should have been obvious. My Local host was implementing JSON with Guard running. With Guard only working in my development mode, JSON was installed on on development. Installed on Production and presto...
Feel kinda dumb for not having noticed this sooner! Thanks for all the help Dave & Keith

Answer 1

I'm pretty sure the undefined method 'encoding' for #<String... error has to do with running the app on ruby 1.8.7 vs. 1.9.2 or higher. i.e. it looks like your Live server is running 1.8.7 or possibly Ruby Enterprise Edition.
If you can, switch your live server to a ruby 1.9.2 version and see if that fixes it. Otherwise I'll dig in a little more this weekend.
Cheers!
-kw