APIs

APIs (Application Programming Interfaces) provide a way for applications to communicate with each other. We already consumed an API earlier in the day: Github API. We managed to communicate with Github and get important information. We - the client - can use this information in a number of different ways. Our client, in this case, is a Web page but it could have easily been a Mobile Application, or a TV setbox etc...

Let's watch this video about APIs - What is an API

Exercise: Let's expose the posts.json as an API for other clients to consume through the url /api/get-posts. Hint: make use res.sendFile

REST API

REST (REpresentational State Transfer) and RESTful APIs provide a way (an architecture) for building APIs that is simple and scalable.

There are many constraints and aspects to building a REST API, but one fundamental constraint is the use of a URL (Uniform Resource Locator) and HTTP Methods (GET, POST, PUT, DELETE etc..)

In our endpoint that we just created /api/get-posts, the get part of the URL is redundant as the HTTP Method GET already tells that we are GETting a Resource. The Resource in this case is called posts.

Exercise: Let's rename our endpoint to /posts so that it follows RESTful architecture.

What would the endpoint for creating posts be called?

Watch: https://www.youtube.com/watch?v=7YcW25PHnAA - What is a REST API (up to 3 minutes)

REST is a big topic that we will revisit again. The table below from Wikipedia shows how a typical RESTful API would look like.

Wikipedia

For now, remember when building APIs, to use Resource names to identify your endpoints and make use of the HTTP methods (Verbs) to describe operations performed on those resources.