9.5. HTTP Client

Overview

We will write a small CLI tool that gets the follower count and the full name of a specific Github user.

Information about a Github user we can obtain from the Github REST API under https://api.github.com/users/<user>. Besides many other information a call to https://api.github.com/users/mitchellh returns the following information:

{
  "login": "mitchellh",
  ...
  "name": "Mitchell Hashimoto",
  ...
  "followers": 9973,
  ...
}

The Github API limits the number of unauthenticated requests per IP to 60 per hour. So it is likely that you get a HTTP response code of 429 (Too Many Requests) and no answer.

To send more requests from one IP you have to generate a personal access token (you don’t have to select any permission/scope) and send it as part of the Authorization header:

Authorization: Bearer <your token>

Tasks

1. Create CLI tool github-info which takes a username as argument and prints the users full name and the number of followers.
2. Read the personal access token from the environment variable GITHUB_TOKEN and send it with the API request.
3. Github returns info about the ratelimiting in the HTTP headers of the response. Add an option -debug which shows the number of remaining requests (header x-ratelimit-remaining).

The result should look similar to this:

$ ./github-info mitchellh
name: Mitchell Hashimoto
followers: 9973

After task 3 with debug flag:

$ ./github-info -debug mitchellh
remaining requests: 48
name: Mitchell Hashimoto
followers: 9973

Tips

Check out the examples in 5.3. HTTP Client and 5.2. JSON.

debug := false

flag.BoolVar(&debug, "debug", debug, "show additional information about rate limiting")

flag.Parse()

if flag.NArg() < 1 {
	// missing arugments
}

userName := flag.Arg(0)

Solution

https://github.com/acend/go-basics-training-examples/tree/master/github-info