Question

I would like to create a button so that a user can enroll in a course. The enrolling model belongs_to users and courses and should keep track of enrollment.

I have the following code displayed as a button-form on a course page (looks fine):

<% @enroll = current_user.enrollings.build(course_id: @course.id) %>
<%= form_for(@enroll) do |f| %>  
    <div><%= f.hidden_field :course_id %></div>
    <%= f.submit "Enroll", class: "btn btn-large btn-primary" %>
<% end %>

I have a resources route for enrollings, and when the user clicks on the button, the page goes to /enrollings.

This is the code in the enrolling controller:

def create    
@course = Course.find(params[:course_id])
current_user.enroll!(@course)
end

When I click on the button, I get the following error message:

ActiveRecord::RecordNotFound in EnrollingsController#create

Couldn’t find Course without an ID

Why isn’t it passing the course_id with the form? How do I setup the controller correctly?

Answer 1

Try this instead:

<div><%= hidden_field_tag "course_id", @course.id %></div>