Are there any Wi-Fi modules for the Arduino Uno that may connect to an external Wi-Fi Antenna? I have an Arduino Uno I need to connect to Wi-Fi to make HTTP POST Requests to a Raspberry Pi Web Server.

The Arduino is located only about 30 feet from the AP, but there is a brick wall in the line of sight, and it is in a metal outdoor enclosure. For that reason, I wanted to attach an external Wi-Fi Antenna which would stick out a sealed hole in the enclosure.

I was contemplating using an ESP8266 Wi-Fi module, but it does not look like there is an easy way to attach the antenna.

What would be the best Wi-Fi module to which I could attach an external antenna for an Arduino Uno?
There are variants of ESP8266-based modules which include a connection for an external antenna. The ESP-02, ESP-05 and ESP-07 modules all feature a U.FL socket.

Effectively, they are an ESP8266 mounted on a carrier board with a U.FL socket.

If you already have some code to suit an ESP8266-based module, this will avoid having to rewrite for a different unit.