Rails resource with AJAX - ruby-on-rails

Question

In rails, what kind of AJAX call would need to be made in order to create and modify resources. Say if i had a resource like this
Man(age: integer, country_from:string, residence:string)
Now how would this be made through an AJAX call (like sending post to my create function, how would parameters be sent in, how would my controllers be setup). Be detailed, my AJAX is very, very, very weak. (right now i have my Man made like rails generate scaffold Man age:int country_from:string ...)
PS
Im using rails 3

Answer 1

So I believe there are two sides to this: the javascript and the controller changes.
In your controller you need to ensure it can return json output (or xml or whatever your chosen ajax-y output is):
def man
# do your work
return_data = {}
# initialize your return data
respond_to do |format|
render :json => return_data.to_json, :layout => nil
end
end
There are many ways to generate your json output but basically you have to make sure it's in a shape that is easily consumed on the view javascript.
I use jQuery and here's the code to execute an ajax call:
function foo(some_param) {
$.ajax({
type: 'GET',
url: "/<controller>/man?FOO=" + some_params,
dataType: 'json',
success: handle_success,
error: handle_errors
}
function handle_success(data) {
# process return JSON. it's a javascript object corresponding to the shape
# of your JSON. If your json was a hash server side, it will be an 'object', etc
}
function handle_error(data) {
# handle error cases based upon failure in the infrastructure, not
# failure cases that you encounter due to input, etc.
}
You can tie the foo function to some button or onclick as you desire.
I am not sure this is complete enough. Let me know if you need more detail, etc.

Answer 2

Rails 3 can help by telling the form that you want it to be "remote" (ajax)
<%= form_for #man, :remote=>true do |f| %>
<div class="field">
<%= f.label :man %>
<%= f.text_field :man %>
</div>
<%= f.submit "Save", :disable_with=>"Saving..."%>
<% end %>
in your Controllers
class MansController < ApplicationController
respond_to :js, :html
def update
#man = Man.find(params[:id])
#man.update_attributes(params[:man])
respond_with #man
end
end
Then, you can have
/app/views/mans/update.js.erb
<% if #man.errors.any? %>
alert("This is javascript code that either renders the form in place of the other form");
<% else %>
alert("success!")
<% end %>
Note: Wherever I say "mans" above, it might be "men"