Guides to making a library to wrap an API

A good place to start is playing with a library like Tesla or HTTPoison. Those libraries provide a simplified interface around more lower level HTTP clients like Hackney or Mint. You’ll probably need a way to configure authentication; ideally through function parameters or options. Tesla has a decent solution to build an authenticated client at run-time which is helpful to avoid imposing configuration methods on your users.

There are 4 main components to think about with a REST API wrapper:

• The External Service who’s API you’re wrapping, how to authenticate with it, and what requests and responses can be made.
• The Consumer of your library (e.g. the Business Logic), what it cares about, and the minimal set of knowledge it should have about how to interact with the service.
• Your API Wrapper library, how it’s configured, how it authenticates with the External Service, how it validates incoming commands, and how it handles responses from the service.
• The HTTP Client (e.g. Hackney/Mint) that does the actual work of executing an HTTP Request through the network stack.

The most important part is providing a clean interface between your business logic (consumer of the API Wrapper) to hide implementation details like HTTP request/response. Outside of that you’ll probably want to spend time thinking about how to configure your library.

These resources are worth looking at for Library configuration in general:

• https://michal.muskala.eu/post/configuring-elixir-libraries/
• https://hexdocs.pm/elixir/master/library-guidelines.html

Hope this helps!

Thanks, I got a lot to learn!

Are there any examples of wrapping a REST API that need an access token and a refresh token?

Would you use Req now?

Yes, Req is the way to go now. Also see this article: