What is a REST API?
What is a REST API?
What is REST?
REST stands for Representational State
Transfer. It’s a software architectural style for implementing web services.
Web services implemented using the REST architectural style are known as the
RESTful web services.
REST API
A REST API is an API implementation
that adheres to the REST architectural constraints. It acts as an interface.
The communication between the client and the server happens over HTTP. A REST
API takes advantage of the HTTP methodologies to establish communication
between the client and the server. REST also enables servers to cache the
response that improves the application’s performance.
The communication between the client
and the server is a stateless process. By that, I mean every communication
between the client and the server is like a new one.
There is no information or memory
carried over from the previous communications. So, every time a client
interacts with the backend, the client has to send the authentication
information to it as well. This enables the backend to figure out whether the
client is authorized to access the data or not.
When implementing a REST API, the
client communicates with the backend endpoints. This entirely decouples the
backend and the client code.
Let’s break it down what this means.
REST endpoint
An API/REST/Backend endpoint means the
URL of the service that the client could hit. For instance,
https://myservice.com/users/{username} is a backend endpoint for fetching the
user details of a particular user from the service.
The REST-based service will expose
this URL to all its clients to fetch the user details using the above stated
URL.
Decoupling clients and the backend service
With the availability of the
endpoints, the backend service does not have to worry about the client
implementation. It just calls out to its multiple clients and says, “Hey Folks!
Here is the URL address of the resource/information you need. Hit it when you
need it. Any client with the required authorization to access a resource can
access it”.
With the REST implementation,
developers can have different implementations for different clients, leveraging
different technologies with separate codebases. Different clients accessing a
common REST API could be a mobile browser, a desktop browser, a tablet or an
API testing tool. Introducing new types of clients or modifying the client code
does not affect the functionality of the backend service.
This means the clients and the backend
service are decoupled.
Application development before the REST API
Before the REST-based API interfaces
became mainstream in the industry, we often tightly coupled the backend code
with the client. Java Server Pages (JSP) is one example of this.
We would always put business logic in
the JSP tags. This made code refactoring and adding new features difficult
because the business logic spread across different layers.
Also, on the backend, we had to write
separate code/classes for handling requests from different types of clients. We
needed a separate servlet for handling requests from a mobile client and a
separate one for a web-based client.
After REST APIs implementation backend
developers didn’t need to worry about the type of the client. All the devs had
to do was provide the service endpoints to the clients and they would receive
the response in a standard data transport format like JSON. It was now the
responsibility of the clients to parse and render the response data.
This cut down a lot of unnecessary
work for the backend developers. Also, adding new clients became a lot easier.
Now, with REST, we can introduce any number of new clients without having to
worry about the backend implementation.
In today’s application development
landscape, there is hardly any online service implemented without a REST API.
Want to access the public data of any social network? Just use their REST API.
API Gateway
Comments
Post a Comment