rails ajax requested form has wrong method - ruby-on-rails

Question

I have a _form.html.erb partial that comes from the standard rails 3 template for the model project.
#view:
<div id="content">
<%= link_to 'Edit', edit_project_path(#project), :remote => :true %>
</div>
#projects controllers
def edit
#project = Project.find(params[:id])
respond_to do |format|
format.html # edit.html.erb
format.js { render "form.js.rjs" }
end
end
#form.js.rjs
page.replace_html "content", :partial => 'form'
#_form.html.erb
<%= form_for(#project) do |f| %>
<% if #project.errors.any? %>
<div id="error_explanation">
<h2><%= pluralize(#project.errors.count, "error") %> prohibited this project from being saved:</h2>
<ul>
<% #project.errors.full_messages.each do |msg| %>
<li><%= msg %></li>
<% end %>
</ul>
</div>
<% end %>
<p>
<%= f.label :name %>
<%= f.text_field :name %>
</p>
<div class="actions">
<%= f.submit %>
</div>
<% end %>
While i click that link to edit a project, the form does come through through ajax, but the method for the form is now post instead of put. which means as i submit, it will create new projects with the same attributes as the existing one that I am editing b/c of the create method that's called upon receiving a post request.
I know that form_for(#project) rely on record id to tell whether it's new or not, I looked through all the sources for form_for, form_tag, extras_tags_for_form, form_tag_html but cannot find a place where they specify which method for the form tag is to be used. The closest place where it defines the method is in extra_tags_for_form, but in that method, it is merely sieving through the :method option hash that's already passed to it, but from where is this :method option passed? I cannot find.
any ideas?

Answer 1

You are on the right track, form_form(obj) will look at the objects dirty flag to figure out what to do with it. That doesn't mean you can't tell it what to do though :)
form_for actually has a few hashes in its optional params, :method lives inside :html. so to force it to be put, just do something like this
form_for #project, :html => {:method => :put} do |f|