Creating a Simple REST API with Flask

Flask is a micro web framework written in Python that is used to create web applications. It is lightweight and easy to use, making it a popular choice for developers. In this tutorial, we will cover how to create a simple REST API using Flask.

Step 1: Setting up Flask
To begin, you will need to install Flask. You can do this by running the following command in your terminal:

pip install Flask

Next, create a new Python file for your Flask application. Inside this file, import Flask and create a new instance of the Flask class:

from flask import Flask

app = Flask(__name__)

Step 2: Creating routes
In Flask, routes are used to define the URL paths that your application will respond to. You can create routes using the @app.route decorator. Let’s create a simple route that will return a greeting message:

@app.route('/')
def hello_world():
    return 'Hello, World!'

Step 3: Running the Flask application
To run your Flask application, you can simply call the run method on the Flask instance:

if __name__ == '__main__':
    app.run()

Now, if you run your Python file, you should see the Flask development server start up and display a message that the server is running. You can then navigate to http://localhost:5000 in your browser to see the greeting message.

Step 4: Creating a simple REST API
To create a simple REST API with Flask, you will need to define routes that correspond to the HTTP methods for interacting with resources. For example, you can create routes for handling GET, POST, PUT, and DELETE requests.

Let’s create a simple API route that will allow users to get a list of items:

items = ['item1', 'item2', 'item3']

@app.route('/items', methods=['GET'])
def get_items():
    return {'items': items}

In this example, we have defined a route /items that will return a JSON response containing a list of items. The methods=['GET'] parameter specifies that this route will only respond to GET requests.

Step 5: Testing the API
To test your API, you can use tools like Postman or cURL to make requests to your API routes. For example, you can use cURL to send a GET request to the /items endpoint:

curl http://localhost:5000/items

You should see a JSON response containing the list of items that we defined earlier.

Congratulations! You have successfully created a simple REST API with Flask. Flask’s simplicity and flexibility make it a great choice for building web applications and APIs.