Complex form with Rails

I have a form where I'd like to create a parent record and a child record at the same time. For a simple example let's say its a Company with the first Employee.

in my controller I do something like:

def new
    @company = Company.new
    @company.employees.new
end

and in my view this:

<%= form_for(@company) do |form| %>

    <div>
        <%= form.label :name %>
        <%= form.text_field :name %>
    </div>

    <%= form.fields_for :employees do |employee_form| %>

        <div>
            <%= employee_form.label :name %>
            <%= employee_form.text_field :name %>
        </div>

    <% end %>

<% end %>

and back in my controller again:

def create
    @company = Company.new(params[:company])
    @com开发者_运维问答pany.employees << Employee.new(params[:company][:employees_attributes]["0"])

    # save stuff
end

Question 1:

I couldn't get the employee collection on the company to be populated with the single employee created in the form. When I looked at the params I found the [:employees_attributes]["0"] stuff.

What I have works, but is there a cleaner way to do this?

Question 2:

If the validation doesn't pass for the employee I get a generic "Employees is invalid" instead of the Name required validator message. I get I am calling save on the collection and rails is doing its best to bubble a validation error up, but is there a cleaner way to do this so I can get the errors specific to the employee?

In Short

How can I clean this up so the related models are created automatically from the params, and so that I get the validation messages for a single employee.

Thanks for looking.

1) fields_for arranges for the child objects attributes to be nested inside the parent objects attributes in the params hash that gets sent back to the controller action. To get Rails to automatically update the child objects tell the parent model to accept nested attributes using the accepts_nested_attributes_for declaration.

2) There is an errors object for every ActiveRecord object. Loop through the errors list and display the messages.

Best way to achieve this is to create a partial and a view helper method that will take render the errors for you. then replace the generated errors messages in the forms with a call to your render_error_messages method. You have all the code to do this already in the generated forms. You just need to refactor that code into a partial, create the helper - which should accept an array of model names as a parameter then do what you want with the info. Wither render a partial for each model or render a partial that will deal with child objects as well as the parent object. Totally your call.

3) Change your new action to build rather that create a new child object so instead of

def new
    @company = Company.new
    @company.employees.new
end

do this

def new
    @company = Company.new
    @company.employees.build
end

4) Watch those Railscasts to see how accepts_nested_attributes works

http://railscasts.com/episodes/196-nested-model-form-part-1

and

http://railscasts.com/episodes/197-nested-model-form-part-2

Update

So how does the above information leave you in relation to your questions.

1) What I have works, but is there a cleaner way to do this?

You've fixed the new action as per point 3 above right? Now your create action can look like this

def create
    @company = Company.new(params[:company])

    # save stuff
end

Which is much cleaner as it has reverted to the original generated create action. You may not think that's much of an update and therefore not that much cleaner. Well in isolation you'd be right. But consider that you could add as many relationships as you like ad add as many fields_for declarations as you like nd you could turn the user -> employee relationship into a has_many (I know that you wouldn't). You could do all that and your create and update actions stay EXACTLY the same and that's why it's cleaner.

2) is there a cleaner way to do this so I can get the errors specific to the employee? Given my response in point 2 above you know that there is an errors object on the employee object as well as on the user object right? You also know now that you can loop through that errors object to get the messages right? So you could do this

  <% if @user.employee.errors.any? %>
    <div id="error_explanation">
      <h2><%= pluralize(@user.employee.errors.count, "error") %> prohibited this user from being saved:</h2>

      <ul>
      <% @user.employee.errors.full_messages.each do |msg| %>
        <li><%= msg %></li>
      <% end %>
      </ul>
    </div>
  <% end %>

At the risk of repeating myself I'll just say that you should refactor your error messages view code into a partial that will take any object as a parameter then you can call it from any view thus enabling you to change the styling and the functionality for all your forms.

Hope that's clearer