Question

I asked a question similar to this one about a week ago, but this is a slightly different perspective on it. The nature of the question involves being redirected to the correct controller.

I have a single resource, posts, and I have 4 different categories these posts can be under. I want each of these categories to be particular to a single controllers, and so I have the following in my routes.rb:

resources "code", :controller => :code_posts, :as => :code
resources "sports", :controller => :sports_posts, :as => :sports
resources "gaming", :controller => :game_posts, :as => :gaming
resources "the-nation", :controller => :personal_posts, :as => :the_nation

So now I can access posts through URLs like, for example, /code/1, /sports/34 to access the same post resource, but with each controller focusing on a single scope, namely a particular category.

This is all well and good, but my issue comes up when I try to edit or save particular posts. I have the following partial _form.html.erb (rendered in the new and edit views) in all the view folders for their particular controller:

<%= form_for @post do |f| %>
<div class="field">
  <%= f.label :author %><br/>
  <%= f.text_field :author %>
</div>
<div class="field">
    <%= f.label :title %><br/>
    <%= f.text_field :title %>
</div>
<div class="field">
  <%= f.label :category %>
  <%= f.select :category_id, Category.all.collect {|c| [c.name, c.id] }, {:include_blank => true} %>
</div>
<div class="field">
  <%= f.label :summary %><br/>
  <%= f.text_area :summary, :rows => 5 %>
</div>
<div class="field">
  <%= f.label :body %><br/>
  <%= f.text_area :body %>
</div>
<div class="field">
  <%= f.label :tag_tokens %><br/>
  <%= f.text_field :tag_tokens, "data-pre" => @post.tags.map(&:attributes).to_json %>
</div>
<div class="field">
    <%= f.submit "Submit" %>
</div>
<% end %>

So whenever I create or update a post, through whichever controllers, I always get redirected back to /posts/4, /posts/123, /posts/:id, whatever. I want to get redirected to the particular controller the post being edited or created lives under. So if I go to /code/new, and submit the new post, I want to be redirected to /code/1234, and not /posts/1234. How can I do this? For some reason I’m just having major mental mind blocks this morning. Thanks.

EDIT Updated <%= form_for @post do |f| %> to <%= form_for @post, :url => code_url(@post) do |f| %> and it works for /code/1/edit but not /code/new. When trying to access a new post form, I get the following error:

No route matches {:action=>"show", :controller=>"code_posts", :id=>#<Post id: nil, author: "Les Peabody", summary: nil, body: nil, created_at: nil, updated_at: nil, title: nil, category_id: 1, slug: nil>}

This is my CodePostsController#new method

def new
  @post = Post.new(:category => Category.find_by_name("Programming"), :author => current_user.full_name)
end

Answer 1

So, ultimately what is important is how the form gets turned into HTML. If you look at the differences between a form that is meant for editing, and a form that is meant for a new object, there is only one thing that is ever really different that matters – the action URL.

In the case of a new form, the form tag should look something like:

<form accept-charset="UTF-8" action="/code" class="new_post" id="new_post" method="post">

and in the case of an edit form:

<form accept-charset="UTF-8" action="/code/1" class="edit_post" id="edit_post_1" method="post">

The only thing that matters to rails however is the name of the input elements (which are constant in both forms) and the action attribute in the form tag. That tells Rails whether or not it’s rendering the edit or create action.

Since we’re splitting up control of a single resource through multiple controllers, the standard form_for @post will not suffice since Rails can no longer automate the rendering process through convention (as we’re doing a very unconventional thing). It is necessary to do some manual labor. The following will do the trick.

Convert the partial to the following:

<%= form_for @post, :url => path do |f| %>
<div class="field">
  <%= f.label :author %><br/>
  <%= f.text_field :author %>
</div>
<div class="field">
    <%= f.label :title %><br/>
    <%= f.text_field :title %>
</div>
<div class="field">
  <%= f.label :category %>
  <%= f.select :category_id, Category.all.collect {|c| [c.name, c.id] }, {:include_blank => true} %>
</div>
<div class="field">
  <%= f.label :summary %><br/>
  <%= f.text_area :summary, :rows => 5 %>
</div>
<div class="field">
  <%= f.label :body %><br/>
  <%= f.text_area :body %>
</div>
<div class="field">
  <%= f.label :tag_tokens %><br/>
  <%= f.text_field :tag_tokens, "data-pre" => @post.tags.map(&:attributes).to_json %>
</div>
<div class="field">
    <%= f.submit "Submit" %>
</div>
<% end %>

The path variable in there is a variable passed in through the :locals mechanism in the partial render, like so:

new.html.erb

<%= render :partial => "form", :locals => {:path => code_index_path} %>

and edit.html.erb

<%= render :partial => "form", :locals => {:path => code_path(@post)} %>

The nice thing with this solution is you can DRY up the code too by placing _form.html.erb in app/views/layouts or app/views/posts and reuse it in all of the new and edit views for all controllers that manipulate the Post resource in a consistent fashion. So rather than having:

<%= render :partial => "form", :locals => {:path => code_path(@post)} %>

we have:

<%= render :partial => "layouts/form", :locals => {:path => code_path(@post)} %>