Converting Rails 2 routes to Rails 3 - ruby-on-rails

Question

Like in my first question from yesterday, I'm still doing that tutorial.
I've encountered another issue with the Rails 2 / Rails 3 routing differences.
So my question is: How do you "translate" this:
<%= form_remote_tag(:controller => "posts", :action => "create") do %>
to Rails 3 routing?
Edit: This is the error code I get :
Showing C:/Users/Lunasea/Web-Site/Standart/app/views/posts/_message_form.html.erb where line #5 raised:
C:/Users/Lunasea/Web-Site/Standart/app/views/posts/_message_form.html.erb:5: syntax error, unexpected tASSOC, expecting '}'
...pend= form_tag {:controller => "posts", :action => "create"...
C:/Users/Lunasea/Web-Site/Standart/app/views/posts/_message_form.html.erb:5: syntax error, unexpected ',', expecting '}'
...rm_tag {:controller => "posts", :action => "create"}, :remot...
C:/Users/Lunasea/Web-Site/Standart/app/views/posts/_message_form.html.erb:5: syntax error, unexpected tASSOC, expecting keyword_end
...action => "create"}, :remote => true do #output_buffer.safe_...
C:/Users/Lunasea/Web-Site/Standart/app/views/posts/_message_form.html.erb:12: syntax error, unexpected keyword_ensure, expecting keyword_end
C:/Users/Lunasea/Web-Site/Standart/app/views/posts/_message_form.html.erb:14: syntax error, unexpected $end, expecting keyword_end
The content of _message_form.html.erb:
<% if logged_in? %>
<!--<% form_for product, :url => {:action => 'add_to_cart', :id => product.id}, :remote => true do %>-->
<!--<%= form_remote_tag(:controller => "posts", :action => "create") do %>-->
<%= form_for{:controller => "posts", :action => "create"}, :remote => true do %>
<%= label_tag(:message, "What are you doing?") %><br />
<%= text_area_tag(:message, nil, :size => "60x2") %><br />
<%= submit_tag("Update") %>
<% end %>
<% end %>

Answer 1

You'd use a form_tag and pass :remote => true to it…
form_tag :url => {:controller => 'posts', :action => 'create'}, :remote => true
(Make sure you've included jQuery UJS or equivalent Prototype library, because Rails no longer includes the javascript inline like it used to.)

Answer 2

I cite here from the book Fernandez: The Rails 3 Way section 11.13
PrototypeHelper
PrototypeHelper has been heavily modified ... The following helper methods were removed and made available in an official Prototype Legacy Helper
...
form_remote_for
form_remote_tag
That is the reason for your error. You have to translate that to the new syntax with the option :remote => true to indicate a remote call (AJAX).
So the following should work:
<%= form_tag({:controller => "posts", :action => "create"}, {:remote => true}) do %>
...
<% end %>
See the API for Rails and search there for form_tag for additional information.

Answer 3

Your problem is that you use <!-- and --> to hide old code. Rails will still execute that code. Use the following format instead:
<% if logged_in? %>
<%-# form_for product, :url => {:action => 'add_to_cart', :id => product.id}, :remote => true do %>
<%-#= form_remote_tag(:controller => "posts", :action => "create") do %>
<%= form_for{:controller => "posts", :action => "create"}, :remote => true do %>
<%= label_tag(:message, "What are you doing?") %><br />
<%= text_area_tag(:message, nil, :size => "60x2") %><br />
<%= submit_tag("Update") %>
<% end %>
<% end %>

Answer 4

form_remote_tag is not there in the Rails 3
Use
form_tag :url => {...}, :remote => true
instead
What this means is that all previous remote_ helpers have been
removed from Rails core and put into the Prototype Legacy Helper. To
get UJS hooks into your HTML, you now pass :remote => true instead.
For example:
form_for #post, :remote => true
http://edgeguides.rubyonrails.org/3_0_release_notes.html

Answer 5

The error is saying there is a syntax problem in the message form template. My guess is that you are missing a <% end %> to close the do in your form_remote_tag call.