update partial with object content in rails 4 - ruby-on-rails

Question

Well, i have a problem, and i was wondering if it could be solved with rails only.
I have setup a view (home.html.erb) vith 3 partials, like this:
<%provide :title, 'Reader'%>
<div class = "row">
<div class = "span4">
<div class = "row">
<%= render 'layouts/add_subscription'%>
</div>
<div class = "row">
<%= render 'layouts/subscription_list'%>
</div>
</div>
<div class = "span8">
<div class = "row">
<%= render 'layouts/view' %>
</div>
</div>
</div>
where subscription_list shows up a list of links pointing to the list action after a redirection, each of them with the id of the subscription:
<ul>
<% current_user.subscriptions.each do |s| %>
<li><%= link_to s.url, "/list?s_id=#{s.id}" %></li>
<% end %>
</ul>
So, each of these links points to the list action in the controller, which tries to fetch the feed list of the subscription just clicked, and update the home view with the list of titles for the selected subscription:
def list
s_id = params[:s_id]
feed = ""
if !s_id.blank?
s = Subscription.find_by(id: s_id)
feed = Feedzirra::Feed.fetch_and_parse(s.url)
#render partial: "layouts/view", :locals => {:f => feed}
end
The problem is that I'm stuck at this point. I've tried to do a redirect_to home_path with feed as a parameter, and even a render (the line before the end of the list method) to see what happened, but nothing updates 'just' the layouts/view partial:
<ul>
<% if defined? feed and !feed.blank? %>
<% f.entries.each do |entry|%>
<li><%= entry.title %></li>
<% end %>
<% end %>
</ul>
So, I was wondering if it's possible to update the partial and see the result after a page reload using only rails methods, or if it can/must be done using javascript, and a clue to how to do this. Thanks in advance.

Answer 1

The goal you want to achieve is to show feed entries in the home.html.erb after clicking a link.
You can do it by pointing your links to the home action instead of list so that rails will automatically render your home.html.erb view and
you have to assign the instance variable #feed so it will be visible in your view.
You can do it like this (refactored a bit):
controller
def home
s_id = params[:s_id]
if s_id.present?
s = Subscription.find_by(id: s_id)
#feed = Feedzirra::Feed.fetch_and_parse(s.url)
end
end
layout/view
<ul>
<% if #feed.present? %>
<% #feed.entries.each do |entry|%>
<li><%= entry.title %></li>
<% end %>
<% end %>
</ul>
I'm not sure what is the path to your action, I assume here that home is the root ("/")
layouts/subscription_list
<ul>
<% current_user.subscriptions.each do |s| %>
<li><%= link_to s.url, "/?s_id=#{s.id}" %></li>
<% end %>
</ul>