File upload field causing ActionController::InvalidAuthenticityToken exception

Question

Using rails 4, and trying to add a file field to an existing form, using simple_form and paperclip.

Here's the critical part of the form:

<%= simple_form_for(@employee, html: { class: 'form-horizontal requires', multipart: true}, remote: true) do |f| %>

    <%= f.input :avatar %>

<% end %>

Everything works ok, unless I actually submit the form with an uploaded file. Then, I get this:

ActionController::InvalidAuthenticityToken in EmployeesController#update

What am I doing wrong here?

Answer 1

The simplest solution would just be to add authenticity_token: true to your form. Like this:

<%= form_for @employee, html: { class: 'form-horizontal requires'}, multipart: true, remote: true, authenticity_token: true  do |f| %>
  <%= f.input :avatar %>
<% end %>

Answer 2

I was with the same problem. <%= token_tag form_authenticity_token %> didn't work for me.

Install gem remotipart solved my problem. remotipart