Let’s talk about what makes up a REST API. It is one of the most logical, efficient, and widely used API creation standards.
Understand all the benefits of REST
REST stands for Re presentational S tate T ransfer (or transfer of representation state , in French), and constitutes a set of standards , or architectural guidelines that structure the way of communicating data between your application and the rest of the world, or between different components of your application.
We use the adjective RESTful to describe REST APIs. All REST APIs are one type of API – but not all APIs are RESTful!
RESTful APIs rely on the HTTP protocol to transfer information – the same protocol on which web communication is based! So when you see http at the beginning of a URL, like http : //twitter.com – your browser is using HTTP to make a request from that website to the server. REST works the same way!
There are six key architectural guidelines for REST APIs. Let’s see what it’s all about:
# 1: Client-server separation
One of the standards of REST is the separation of client and server . We touched on the issue of clients and servers a bit in the previous chapter, it’s time to dig deeper!
A client is the one who will use the API. It can be an application, browser, or software. For example: as a developer you might be using the Twitter API. As I said before, a client can also be software or a browser, whether it’s Chrome, Safari, or Firefox. When a browser goes to twitter.com, it makes a request to the Twitter API and uses the data from the API so that you can access the latest tweets.
A server is a remote computer capable of fetching data from the database, manipulating it if necessary and sending it back to the API, like this big computer in the middle:
Generally, there is a separation between the client and the server. This separation allows the client to be concerned only with retrieving and displaying the information and allows the server to concentrate on storing and manipulating the data. Everyone has their own role!
REST APIs provide a standardized means of communication between client and data . Basically it doesn’t matter how the server is built or how the client is coded, as long as they both structure their communication according to REST architectural guidelines, using the HTTP protocol, they will be able to communicate with each other!
This is especially useful when large teams of developers are working on a single application. You can have one team working independently on the backend while the other is working on the frontend. As the REST API communicates between the two, it makes it easier for developers to scale applications and for teams to work more efficiently.
# 2: Stateless
One of the other unique aspects of the REST API is that they are stateless – stateless , French – meaning that the server does not save any queries or previous answers.
But the role of the server is to store and manipulate the data. How could that work if we don’t keep track of requests, then?
Going back to our API metaphor as a waitress, let’s say you ask your waitress for fries. She goes to the kitchen, collects your fries, and comes back with your order. Perfect !
Houla … but wait! You just remembered that you also want ketchup with your fries. So you ask your waitress, “Excuse me, could I have some ketchup with it?” ” ” With what ? A stateless waitress wouldn’t have a clue what you’re talking about… because she wouldn’t remember you just ordered fries! She is only responsible for transferring orders from the kitchen to the customer.
OK, but then in concrete terms what does this mean for REST APIs?
Since each message is isolated and independent of the rest, you will need to make sure to send with the request that you formulate all the necessary data to be sure to have the most precise answer possible. That would give us something like: “Did I could have ketchup on the fries that I ordered at my table? With all this information, your waitress will be able to identify which fries to add ketchup to!
Being stateless makes every query and response very determined and understandable . So if you are a developer and see someone else’s API request in already existing code, you will be able to understand the purpose of the request without context!
# 3: Cacheable
The response should contain information on whether or not the client can cache the data , or back it up. If the data can be cached , the response must be accompanied by a version number. So if your user makes the same request twice (i.e. wants to see a page again) and the information has not changed, then your server does not need to search for the information once. second time. Instead, the client can just cache the data the first time and then load the same data again the second time.
Efficient caching can reduce the number of times a client and server have to interact, which can help speed up load time for the user!
You may have heard the term cache in reference to, for example, “Refresh your browser cache”. A cache is a way of saving data in order to be able to respond more easily to future requests which will be identical . When you go to many websites from your browser, your browser can save these requests so that it can complete the site you want to reach on its own or load the page faster the next time you visit it. Convenient !.
# 4: Uniform Interface
When creating a REST API, developers agree to use the same standards. Thus, each API has a uniform interface . The interface is a contract between the customer and the service, which is shared by all REST APIs. This is useful, because when developers use APIs, it allows them to be sure that they understand each other.
A REST API of one application can communicate the same way with another entirely different application.
# 5: Layered system
Each component that uses REST does not have access to components beyond the precise component with which it interacts.
What… what? That is to say ?
This means that a client that connects to an intermediary component has no idea what that component interacts with next. For example, if you make a request to the Facebook API to retrieve the latest posts: you have no idea what components the Facebook API communicates with.
This encourages developers to create independent components, making it easy to replace or update each one.
# 6: Code on demand
Code on demand means that the server can extend its functionality by sending the code to the client for download. This is optional, as not all clients will be able to download and run the same code – so it’s not usually used, but at least you know it exists!
Discover alternatives to REST APIs
REST is just one type of API. There are alternatives that you will also find useful to know, including SOAP APIs .
SOAP is the acronym for Simple Object Access Protocol , or simple object access protocol , in French. Unlike REST, it is seen as a protocol, not a style of architecture.
SOAP APIs were the most common APIs before REST arrived. REST uses HTTP protocol to communicate, SOAP on the other hand can use multiple means of communication. The concern is the complexity that emerges, as developers need to coordinate to ensure that they communicate in the same way in order to avoid problems. Additionally, SOAP can require more bandwidth, resulting in much longer load times. REST was created to address some of these issues with its lighter weight and more flexible nature.
Nowadays, SOAP is used more frequently in large enterprise applications, since it can add additional layers of security, data privacy, and integrity. REST can be just as secure, but needs to be implemented, that is, to be developed instead of just being integrated like with SOAP.
- Not all APIs are RESTful, and REST APIs have specific architectural guidelines.
- The key benefits of REST APIs are:
- separation of client and server, which helps to scale applications more easily;
- being stateless, which makes API requests very specific and detail oriented;
- the possibility of caching, which allows clients to save data, so they do not have to constantly make requests to servers.
- SOAP is another type of API, but is used more in large companies.