In this blog post, we will explore how to integrate Tornado and Redis in Python to build scalable and efficient web applications.

Why use Tornado and Redis?

Tornado is a popular asynchronous web framework that allows you to handle thousands of simultaneous connections with low latency. It is known for its simplicity and performance, making it a great choice for building fast and scalable web applications.

Redis, on the other hand, is an in-memory data structure store that is often used as a cache or message broker. It offers high-speed data retrieval and can significantly improve the performance of your application by reducing the load on your primary database.

By combining these two technologies, you can take advantage of Tornado’s efficiency and Redis’s fast data access to build highly responsive web applications.

Prerequisites

Before we begin, make sure you have the following installed on your system:

• Python 3.x
• Tornado framework
• Redis server

You can install Tornado and Redis using pip:

pip install tornado redis

Connecting to Redis

To connect Tornado with Redis, we need to use a Redis client library. In this example, we will be using the redis-py library, which is a popular and actively maintained Redis client for Python.

First, let’s import the necessary libraries:

import tornado.ioloop
import tornado.web
import redis

Next, we can establish a connection to the Redis server:

redis_client = redis.Redis(host='localhost', port=6379, db=0)

Make sure to replace localhost and 6379 with the correct values for your Redis server.

Using Redis in Tornado

Now that we have connected to Redis, let’s see how we can use it in a Tornado application. In this example, we will create a simple web application that displays the number of visitors on a specific page.

First, let’s define a Tornado request handler:

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        # Retrieve the number of visitors from Redis
        visitors = redis_client.get('page_visitors')

        # If no visitors found, set it to 0
        if not visitors:
            visitors = 0

        self.write(f"Number of visitors: {visitors}")

Next, we need to define the Tornado application and specify the URL routing:

def make_app():
    return tornado.web.Application([
        (r"/", MainHandler),
    ])

if __name__ == "__main__":
    app = make_app()
    app.listen(8888)
    tornado.ioloop.IOLoop.current().start()

Now, whenever a user visits the main page, the MainHandler will retrieve the number of visitors from Redis and display it on the screen.

You can test the application by running it and accessing http://localhost:8888 in your web browser.

Conclusion

Integrating Tornado and Redis can greatly enhance the scalability and performance of your web applications. With Tornado’s asynchronous nature and Redis’s fast data access, you can build efficient and responsive web applications that can handle a high number of concurrent requests.

By following the steps outlined in this blog post, you should now have a good understanding of how to connect Tornado with Redis in Python.

Happy coding!