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Using Tornado with NoSQL databases

Introduction to NoSQL Databases with Tornado​

Tornado is a powerful Python web framework and asynchronous networking library. In this tutorial, we will learn how to use NoSQL databases in Tornado, specifically focusing on MongoDB as an example.

What is a NoSQL Database?​

NoSQL databases are non-tabular databases that store data differently than relational tables. They're especially good for managing large sets of distributed data. MongoDB is a popular example of a NoSQL database.

Getting Started with MongoDB​

Before we begin, ensure you have MongoDB installed on your machine. You can download it from the official MongoDB website.

Setting Up Python Environment​

Next, we will set up our Python environment. We need to install tornado and PyMongo, which is a MongoDB driver for Python.

pip install tornado pymongo

Building a Simple Tornado Application​

Let's start by building a simple Tornado application. We will create a new file named app.py.

import tornado.ioloop
import tornado.web

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()
    app.listen(8888)
    tornado.ioloop.IOLoop.current().start()

Connecting to MongoDB​

Now we will connect our application to MongoDB. To do this, we will use the pymongo library. Let's modify the app.py file as follows:

from pymongo import MongoClient
import tornado.ioloop
import tornado.web

# Create a MongoDB client
client = MongoClient("mongodb://localhost:27017")

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()
    app.listen(8888)
    tornado.ioloop.IOLoop.current().start()

Interacting with MongoDB​

Let's create a new handler to interact with MongoDB. We will create a 'users' collection and insert a new user into it.

class UserHandler(tornado.web.RequestHandler):
    def get(self):
        # get the users collection
        users = client.mydatabase.users

        # insert a new user
        user_id = users.insert_one({"name": "John", "email": "[email protected]"}).inserted_id

        # write the user id to the response
        self.write(f'User created with id {user_id}')

Don't forget to add the UserHandler to the application routes.

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

Now, when you navigate to http://localhost:8888/user in your browser, a new user should be created in the 'users' collection of the 'mydatabase' database.

Conclusion​

In this tutorial, we've learned how to use a NoSQL database (MongoDB) with the Tornado web framework. We've set up a simple Tornado application, connected it to MongoDB, and interacted with the database. In the next steps, you can build more complex applications by using different MongoDB operations and integrating with other Tornado features.