Introducción a WSGI y ASGI para aplicaciones Python

How do Python applications connect to web servers?

Python applications establish communication with web servers using protocols that facilitate the exchange of information. Traditionally, web servers return HTML that the browser interprets to display the web page. But traditional Python applications use the WSGI (Web Server Gateway Interface) protocol to handle requests and responses. However, with the evolution of Python towards asynchronous programming, the ASGI (Asynchronous Server Gateway Interface) protocol has become relevant. ASGI allows handling multiple requests simultaneously without the need to wait for all of them to be ready.

What is the WSGI protocol and how is it implemented?

The WSGI protocol acts as a bridge between traditional Python applications and web servers. A typical WSGI application receives a request, generates a response and returns it to the web server for processing.

Basic example of a WSGI application with Unicorn

To illustrate the use of WSGI, let's consider a simple example developed in Visual Studio Code using Unicorn, a library that allows you to run Python applications on web servers:

def app(environ, start_response): status = '200 OK' headers = [('Content-type', 'text/plain; charset=utf-8')] start_response(status, headers) return [b "Hello WSGI World"]

This code snippet defines an application that returns a basic greeting. Unicorn is used to handle the execution and connection to the server:

1. Create a WSGIApp.py file with the above code.
2. Install Unicorn with pip install gunicorn.
3. Run the application:

gunicorn --workers 2 --bind 127.0.0.1.1:8000 WSGIApp:app.

When accessing http://127.0.0.1:8000, you will see the message "Hello WSGI World".

What makes the ASGI protocol different?

The ASGI protocol is essential for asynchronous applications built in Python. It facilitates handling multiple requests simultaneously, optimizing execution and taking advantage of the benefits of asynchronism.

When to choose WSGI or ASGI?

Choosing between WSGI and ASGI depends on the needs and nature of your application:

• WSGI is ideal for synchronous applications, especially if you use frameworks like Django without asynchronous support.
• ASGI is recommended for asynchronous applications, such as those developed with FastAPI. It is ideal if you need to handle WebSockets or read and write to disk quickly.

Which frameworks and libraries are suitable for each protocol?

Python offers multiple web development frameworks, and each one is allied with different servers, depending on their characteristics. Here are some examples:

• Django: It can work with WSGI, using uWSGI or with Unicorn. It is also compatible with ASGI to implement asynchronism.
• FastAPI: Not compatible with uWSGI, requires Unicorn for efficient asynchronous execution.

It is crucial to choose the right protocol and library according to the demands of your application to ensure optimal performance.

Explore the many options and configure your development environment to meet your specific needs - we encourage you to keep learning and creating new applications!