Often in web applications you need to temporarily store data in-between requests, such as an error or success message during the Post-Redirect-Get process for a form submission. Frameworks such as Rails and Django have the concept of transient single-use flash messages to help with this. In this post I'm going to look at a way to create your own cookie-based flash messages in Go. We'll start by creating a directory for the project, along with a flash.go file for our code and a main.go file fo...