REST API development in Python

There are many applications and web services on the Web that interact with each other in one way or another. For example, an online store uses payment service tools on its website to accept online payments, or the functions of postal services to calculate shipping costs.

To ensure such interaction, APIs are used – application programming interfaces that make available the functions of one application inside another. One of the most common methods for creating APIs is the REST architectural style.

Almost any programming language can be used to create these API, but there are six REST design principles, also called architectural constraints, that must be followed:

• Separation of frontend and backend. One of the main requirements is that the client and server must function independently of each other. That is, for the client application to work, it is enough to have only the URI of the requested resource, while the server part should not make any adjustments to the client, and can only transfer data via HTTP. If one of these conditions is violated, the API will not work.
• Single interface. All requests that are directed to the same resource should look the same, regardless of who sent them.
• No state saving. REST APIs are stateless. This means that each request sent must contain all the necessary information to process it.

• Caching support. The data transmitted from the server must be cached, and it does not matter where it happens – on the server or client side. This greatly improves the performance of applications and opens up the possibility of scaling them.
• Multilevel system. Using the REST API, the client can access the server not directly, but indirectly through other levels, which can be a proxy server or a load balancer.
• Execute code on demand. This item is optional and applies situationally. The fact is that through the REST API, you can send not only static requests, but also compiled code, such as Java applets. In this case, the code execution should be performed exclusively on demand.

Today, Python is one of the fastest growing programming languages and, according to StackOverflow, even surpassed Java in terms of the number of queries asked on the platform.

The large community of programmers that has formed around the Python language provides developers with many open source libraries in a wide variety of areas that they can use to implement their own projects.

In the context of working with the API, it is worth adding that Python provides tools not only for obtaining data from the protocol, but also for creating your own Python REST API.

There are many approaches to designing and developing APIs, and each programmer chooses the most attractive path for himself. But there are a few basic steps in this process. Let’s consider them in more detail.

Definition of resources

First of all, the programmer needs to determine what resources the API will manage, as well as form their hierarchy.

Definition of endpoints

The next step for the developer is to define the endpoints for each resource. They will depend on what actions the end user will be able to perform using the API.

For example, the API of a payment processing project might have these endpoints:

Selecting the communication format

The two most popular options for formatting data in web services are XML and JSON. Traditionally, XML has been more popular in SOAP APIs, while REST API developers have favored JSON.

JSON works like a Python dictionary, and stores data in key-value pairs. In addition, this type of formatting supports nesting data at different levels, allowing developers to model data of varying complexity. Using JSON is especially relevant when the REST API is paired with a front-end framework like React or Vue.

Creating Successful Responses

After defining the formatting type, you need to determine how the API will respond to HTTP requests. In accordance with the principles of the REST architectural style, such responses must follow the same format and include the correct HTTP status code.

Develop responses to errors

Successful responses work when everything goes according to plan, but in “combat” conditions, unexpected problems can arise with a request, and the REST API must know how to respond to them. Therefore, the developer needs to determine in advance how exactly the responses to errors will be displayed. It is important that such responses contain a description of the problem and a status code to help the user form the correct request.

When developing software products, the API makes it possible to:

• simplify and speed up the project’s entry into the market;
• bring some of the functions into a separate application to increase the level of project security;
• simplify setting up links between various programs and services;
• save development budget.

In addition, in some cases, the API can act as an independent product aimed at solving problems existing on the market.

AVADA-MEDIA develops REST API of any complexity in different programming languages, including Python. We have been working in the market of innovative technologies for more than 10 years, and we use our experience and resources to the maximum to implement projects at a high level.