by automatic tools such as integrated development environments.
</p>

<h2 id="Notation">Notation</h2>
<p>
The syntax is specified using a
<a href="https://en.wikipedia.org/wiki/Wirth_syntax_notation">variant</a>
of Extended Backus-Naur Form (EBNF):
</p>

<pre class="grammar">
Syntax      = { Production } .
Production  = production_name "=" [ Expression ] "." .

* 🔒 Check Content-Type request header before assuming JSON. Initial PR [#2118](https://github.com/tiangolo/fastapi/pull/2118) by [@patrickkwang](https://github.com/patrickkwang).

This change fixes a [CSRF](https://en.wikipedia.org/wiki/Cross-site_request_forgery) security vulnerability when using cookies for authentication in path operations with JSON payloads sent by browsers.