WARNING: Can't verify CSRF token authenticity rails

Question

I am sending data from view to controller with AJAXand I got this error:

WARNING: Can\'t verify CSRF token authenticity

I think

Answer 1

oops..

I missed the following line in my application.js

//= require jquery_ujs

I replaced it and its working..

======= UPDATED =========

After 5 years, I am back with Same error, now I have brand new Rails 5.1.6, and I found this post again. Just like circle of life.

Now what was the issue is: Rails 5.1 removed support for jquery and jquery_ujs by default, and added

//= require rails-ujs in application.js

It does the following things:

1. force confirmation dialogs for various actions;
2. make non-GET requests from hyperlinks;
3. make forms or hyperlinks submit data asynchronously with Ajax;
4. have submit buttons become automatically disabled on form submit to prevent double-clicking. (from: https://github.com/rails/rails-ujs/tree/master)

But why is it not including the csrf token for ajax request? If anyone know about this in detail just comment me. I appreciate that.

Anyway I added the following in my custom js file to make it work (Thanks for other answers to help me reach this code):

$( document ).ready(function() {
  $.ajaxSetup({
    headers: {
      'X-CSRF-Token': Rails.csrfToken()
    }
  });
  ----
  ----
});