CSRF Protection

Introduction
X-CSRF-TOKEN

Introduction

Shadow makes it easy to protect your application from cross-site request forgery (CSRF) attacks. Cross-site request forgeries are a type of malicious exploit whereby unauthorized commands are performed on behalf of an authenticated user. Shadow automatically generates a CSRF "token" for each active user session managed by the application. This token is used to verify that the authenticated user is the one actually making the requests to the application. Anytime you define a HTML form in your application, you should include a hidden CSRF token field in the form so that the CSRF protection middleware can validate the request. You may use the csrf_field helper to generate the token field:

<form method="POST" action="/profile">
    <input type="hidden" name="_csrfToken" value="<?= _csrfToken(); ?>">
    ...
</form>

The VerifyCsrfToken middleware, which is included in the web middleware group, will automatically verify that the token in the request input matches the token stored in the session.

X-CSRF-TOKEN

In addition to checking for the CSRF token as a POST parameter, the VerifyCsrfToken middleware will also check for the X-CSRF-TOKEN request header. You could, for example, store the token in a HTML meta tag:

<meta name="csrf-token" content="<?= _csrfToken(); ?>">

Then, once you have created the meta tag, you can instruct a library like jQuery to automatically add the token to all request headers. This provides simple, convenient CSRF protection for your AJAX based applications:

$.ajaxSetup({
    headers: {
        'X-CSRF-TOKEN': $('meta[name="csrf-token"]').attr('content')
    }
});