Question

I have a form on a page that a user can use to create a course. While I understand how to get provide the user the opportunity to fill in simple things like the course name and description, I also want to assign the user’s id to a teacher_id column. This should be done automatically for the user and they shouldn’t see an opportunity to assign a teacher_id as it should be their id.

Currently the “Create a course” page’s view is this:

<% provide(:title, 'My Classes') %>
<h1>Create a class!</h1>

<div class="row">
   <div class="span6 offset3">
     <%= form_for(@course) do |f| %>

      <%= f.label :name %>
      <%= f.text_field :name %>

      <%= f.label :description %>
      <%= f.text_area :description, :size => "30x6" %>

      <!-- Assign the current user's id to the teacher_id column in the background -->

      <%= f.submit "Create my account", class: "btn btn-large btn-primary" %>
     <% end %>
  </div>
</div>

And the new action in the course controller looks like:

def new
    @course = Course.new
end

What’s the best way to accomplish what I want to do? I’m pretty new to Rails and I haven’t had much experience with forms and all the possibilities. I read a little bit on the hidden_field_tag but I don’t know if that’s the kind of thing I need and I was finding it difficult to get the user’s id in the form anyway. Do I need to make a user instance variable in the controller or can I do it with code in the view somehow.

Thanks for the help.

Answer 1

You can use the hidden_field:

<% provide(:title, 'My Classes') %>
 <h1>Create a class!</h1>

<div class="row">
   <div class="span6 offset3">
     <%= form_for(@course) do |f| %>

      <%= f.label :name %>
      <%= f.text_field :name %>

      <%= f.label :description %>
      <%= f.text_area :description, :size => "30x6" %>

      <%= f.hidden_field :teacher_id, :value => :current_user.id %>

      <%= f.submit "Create my account", class: "btn btn-large btn-primary" %>
     <% end %>
  </div>
</div>

EDIT – to explain how to have the current_user available in the form.

I normally have a session controller that is responsible for login and logout users, creating a session to keep the user logged in.

The create action for example:

  def create
    user = User.find_by_name(params[:name])
    if user && user.authenticate(params[:password])
      session[:user_id] = user.id
      flash[:success] = "Welcome " + current_user.name
      redirect_to user
    else
      flash.now[:error] = "Invalid username/password combination."
      render "new"
    end
  end

If the combination of username and password are correct, it will create a session with the user_id (session[:user_id]).
Now, in your application_controller you can have something like the below:

private
def current_user
  @current_user ||= User.find(session[:user_id]) if session[:user_id]
end
helper_method :current_user

The helper_method allows you to use the current_user in any controller or view in your application.

I hope it helps….