Let's Encrypt is "a free, automated, and open Certificate Authority." They provide free signed certificates as a trusted certificate authority. This tutorial walks through the process of installing certbot and requesting new certificates and renewing existing ones wit Let's Encrypt. If you are just looking to generate your own quick self-signed certificates, check out my tutorial on creating self-signed SSL certificates with OpenSSL.
Web scraping (Wikipedia entry) is a handy tool to have in your arsenal. It can be useful in a variety of situations, like when a website does not provide an API, or you need to parse and extract web content programmatically. This tutorial walks through using the standard library to perform a variety of tasks like making requests, changing headers, setting cookies, using regular expressions, and parsing URLs. It also covers the basics of the goquery package (a jQuery like tool) to scrape information from an HTML web page on the internet.
If you need to reverse engineering a web application based on the network traffic, it may also be helpful to learn how to do packet capture, injection, and analysis with Gopacket.
If you are downloading and storing content from a site you scrape, you may be interested in working with files in Go.
Check out Security with Go, a book I recently wrote, available from Packt Publishing. It covers secure development, red team and blue team topics and is useful for developers and infosec professionals like analysts, investigators, engineers, and pentesters. It's a great book if you want to get to know Go better or if you want to start using Go for security.
Learn how to make a request using the Tor proxy with the Go programming language.
GopherCon, the largest event in the world dedicated to the Go programming language, is being held in Denver, CO this year July 11th-13th. I am speaking about packet capturing in Go using the Gopacket package. The talks will be available on YouTube afterwards.
These practical examples will demonstrate how to work with files including: reading, writing, changing permissions and timestamps, archiving(zipping), compressing, checksum hashing, downloading files over HTTP, buffers, scanners, and links. All examples here use the standard library.
Using freegeoip.net we can get location information about hostnames or IP addresses. The service returns information like country name, latitude, and longitude. This example will use Go and its Unmarshal() function to decode the response in to a usable struct.
The gopacket package provides a Go wrapper for libpcap written in C. It is more than just a simple wrapper though. It provides additional functionality and takes advantage of Go things like interfaces, which makes it incredibly powerful.
The Image interface is at the core of image manipulation in Go. No matter what format you want to import or export from, it ultimately ends up as an Image. This is where the beauty of Go interfaces really shines. Go comes with support for gif, jpeg, and png formats in the standard packages. These examples demonstrate how to programatically generate, encode, decode, write to file, and base64 encode images. We will also cover a little bit about interfaces.