GitHub Client Exercise

Create a project folder in your $GOPATH outside of this repository. A good place would be $GOPATH/src/github.com/yourname/contributors where yourname is your GitHub username.

Part 1: Just Get it Working

Create a program which can call the GitHub API to get a list of contributors for the golang/go repository.

• The API url is https://api.github.com/repos/golang/go/contributors
• Docs for the API in general are https://developer.github.com/v3/
• Docs for the contributors endpoint are https://developer.github.com/v3/repos/#list-contributors
• To get around rate limiting you must generate a personal access token at https://github.com/settings/tokens
• You will be using the net/http package to make your request and the encoding/json package to decode the response. The docs for each of these packages is online: net/http, encoding/json.
• To add the authorization header to the request you must first make the request value, add the header, then use a client's Do method to execute the request.
• You may have problems calling the GitHub API from within a restricted firewalled network. If you do then open a new terminal in the githubmock folder and run the program there. Use the url it provides instead of api.github.com.

A template file is included to get you started.

Part 2: Refactoring

• Refactor your GitHub API client to a type called Client with a method Contributors.
• Move your client code from package main to another package like package github.
• Create a function in package main that uses the client. func printContributors(repo string, c *github.Client) int
• Decouple the printContributors function to depend on an interface instead of the concrete type.

Part 3: Testing

• Add tests for printContributors. Create a mock version of the github client and pass that in. To capture the output you can change the printContributors function to accept an io.Writer where it should print results.
• Add tests for the github package using net/http/httptest.NewServer.

Just for Fun

• Add flags to the main package for specifying the repo to pull. Use the flag package.
• Add a flag to the main package to specify an output file name then encode the results to that file in CSV format. Use the encoding/csv package.
• Create a web app that accepts a repo name then shows the contributor list for that repo