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Implementing HTTPS in Tornado

Introduction​

In this tutorial, we will discuss how to implement HTTPS in Tornado, a Python web framework used for building web applications. HTTPS, or Hypertext Transfer Protocol Secure, is an essential security feature that encrypts the data transferred between a user's browser and a web server. This makes it harder for attackers to intercept and manipulate the data.

Prerequisites​

Before we begin, you should have:

  1. Basic knowledge of Python programming.
  2. Tornado installed on your system. If not, you can install it using pip: pip install tornado.
  3. OpenSSL installed on your system to generate self-signed certificates.

Generating a Self-Signed Certificate​

HTTPS relies on SSL/TLS certificates to secure data. While in production, you would want to use a certificate from a trusted Certificate Authority (CA). For testing purposes, we can use a self-signed certificate.

To generate a self-signed certificate with OpenSSL, run the following commands in your terminal:

openssl req -x509 -newkey rsa:4096 -keyout key.pem -out cert.pem -days 365

When prompted, enter the necessary information to complete the process. The -days 365 option denotes that the certificate will be valid for 365 days.

Implementing HTTPS in Tornado​

To implement HTTPS in Tornado, we need to utilize the built-in HTTPServer class with SSL options. Here is a basic example of a Tornado application with HTTPS:

import tornado.ioloop
import tornado.web
import tornado.httpserver

class MainHandler(tornado.web.RequestHandler):
    def get(self):
        self.write("Hello, world")

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

if __name__ == "__main__":
    app = make_app()
    http_server = tornado.httpserver.HTTPServer(app, ssl_options={
        "certfile": "/path/to/cert.pem",
        "keyfile": "/path/to/key.pem",
    })
    http_server.listen(8000)
    tornado.ioloop.IOLoop.current().start()

In the above code, replace /path/to/cert.pem and /path/to/key.pem with the actual paths to your generated certificate and key files.

Test Your Application​

You can now test your application. Open your web browser and visit https://localhost:8000. As we're using a self-signed certificate, your browser will warn you about the certificate's authenticity. Proceed with caution and accept the risk to continue.

Conclusion​

Implementing HTTPS in Tornado is straightforward and adds an essential layer of security to your application. It's crucial to remember to replace the self-signed certificate with a trusted certificate from a Certificate Authority (CA) before moving your application to production.

In this tutorial, we've learned how to generate a self-signed certificate and use it to implement HTTPS in a Tornado application. With this knowledge, you can ensure that the data transferred between your Tornado application and your users is secure.