Implement a Python REST API with Flask & Flasgger

Building a RESTful API in Python can be straightforward with Flask, a lightweight and flexible web framework. To add comprehensive documentation and interactive features to the API, Flasgger is a powerful tool that integrates Swagger UI with Flask. This article guides you through the process of implementing a REST API using Flask and Flasgger.

What is Flasgger?

Flasgger is a Python library that facilitates the creation and management of Swagger (OpenAPI) documentation for Flask web applications. Swagger is a framework for describing APIs using a common language that allows both humans and computers to understand the capabilities of a web service without access to the source code.

Key features of Flasgger include:

1. Easy Integration: Flasgger integrates seamlessly with Flask applications, allowing developers to add API documentation with minimal configuration.
2. Automatic Documentation: It can automatically generate API documentation from Flask routes and view functions, using docstrings and other metadata.
3. Swagger UI: Flasgger provides a built-in Swagger UI, an interactive web interface that allows users to explore and test API endpoints.
4. Customization: Developers can customize the documentation by defining the schema, adding parameters, responses, and examples directly in the docstrings or using YAML files.
5. Validation: It supports request validation against the defined schema to ensure that incoming requests meet the expected format and constraints.

First API Development with Swagger

Here's a step-by-step guide to creating a Code-First API development with Swagger in Python using the Flask web framework:

Setting up Environment

• Make sure you have Python pre-installed in your system.
• Install these required libraries like Flask and Flask-RESTful as shown below in a command prompt.

pip install flask
pip install Flask-RESTful
pip install flasgger

Create a Flask APP

Create a new Python file named app.py , for example

Output:

Run this file as shown in the code snippet below:

python app.py

Then the app will be running on local host http://127.0.0.1:5000. Open the localhost http://127.0.0.1:5000 and the output will be as shown in the below figure.

👁 s

Integration with Swagger

The Swagger configuration has been expanded to include a title and set the UI version to 3 for a more modern look.

Output

👁 Capture1

Creating one more API

A new class Items has been added, inheriting from Resource. This class handles the /items endpoint.

• Items Class:
  • This class handles two HTTP methods: GET and POST.
  • The get method returns a list of items.
  • The post method adds a new item to the list. For simplicity, the item is returned in the response, and in a real application, it would typically be added to a database or another data store.

Run this file as shown in the code snippet below:

python app.py

• Then the app will be running on local host http://127.0.0.1:5000.
• Open the localhost http://127.0.0.1:5000/apidocs/
• Swagger UI will be opened (Flasgger).
• The GET Api call will be displayed , if there are no errors in the code and environment as shown in below output image.

Output:

Output will be displayed as shown in below image.

👁 Capture3-ezgifcom-resize

👁 Capture-ezgifcom-resize