As a programmer, you typically encounter the notion of a RESTful API in one of two contexts:
- You need to use someone else’s RESTful API that already exists
- You need to implement your own RESTful API for others to use.
When would I need to use someone else’s RESTful API?
As an example, suppose you want your web app to be able to share something to a social network feed.
You might use a RESTful API to do that. For example, Facebook provides the Graph API, a RESTful API which is described this way on this overview page (retrieved 2016-06-30):
The Graph API is the primary way to get data in and out of Facebook’s platform. It’s a low-level HTTP-based API that you can use to query data, post new stories, manage ads, upload photos and a variety of other tasks that an app might need to do.
(As a side note, the definition of what is, and is not, a RESTful API is sometimes a matter of debate. At least according to this StackOverflow post is considered a RESTful API.)
When would I need to develop my own RESTful API?
You would develop your own RESTful API when you want to provide a way for other applications to access a service that you have built over the internet. You can think of a RESTful API as a way of providing remote procedure call:
- The idea of remote procedure call is that inside the other person’s application, they call a function or a method
- Magically though, as if there were a wormhole from their code into yours, when the function/method returns, they get back a result that comes from your app, instead of theirs. Or, something changes inside of your app.
- The magic wormhole is an exchange of an HTTP request and response between their application and yours, over a RESTful API.
Where did the notion of RESTful APIS come from?
Roy Fielding, who was a co-founder of the Apache HTTP Server project, proposed the idea of Representational State Transfer (REST) as part of his Ph.D. dissertation at UC Irvine (go Anteaters!).
It has since become a widely adopted model for building web services based on HTTP.
Testing RESTful APIs Interactively
Two tools for testing RESTful APIs interactively (without writing additional code) are:
curl, a command line tool
- Postman, a GUI tool you can download and run on Windows/Mac/Linux
When testing APIs that use authentication, you may need to get an extension called the “JWT Debugger” and use it to copy the
Authorization: Bearer token value. (TODO: Fill in more detail about this process.) ``
References on RESTful APIs
- Wikipedia article https://en.wikipedia.org/wiki/Representational_state_transfer
- PUT vs. PATCH: https://stackoverflow.com/questions/28459418/rest-api-put-vs-patch-with-real-life-examples/39338329#39338329
- Note that there is the notion of a “PATCH language” (or “PATCH protocol”) some common agreed upon set of operations that both the client and server understand.