Prerequisites: Introduction to REST API
REST stands for Representational State Transfer and is an architectural style used in modern web development. It defines a set of rules/constraints for a web application to send and receive data. In this article, we are going to learn how to create a simple REST API that returns ‘Hello World’, with the help of a flask.
In this article we are going to write a simple flask API for hello world using two methods:
- Using Flask jsonify object.
- Using the flask_restful library with Flask.
Installation
1. Install the python Flask library using the following command.
pip install Flask
2. Install the flask-restful library using the following command.
pip install Flask-RESTful
Method 1: Using Flask ‘jsonify’ object
- Create a new python file named ‘main.py’.
- import Flask, jsonify and request from the flask framework.
- Register the web app into an app variable using the following syntax.
Python3
app = Flask(__name__) |
- Create a new function named ‘helloworld’. This function is going to return the ‘Hello World’ text in JSON format.
- Route the ‘helloworld’ function to your desired URL using the following syntax.
Python3
@app.route('/path_of_the_response', methods=['GET']) def helloworld(): pass |
- Inside the ‘helloworld’ function if request method is ‘GET’ then create a python dictionary with the ‘Hello World’ message.
- Jsonify the python dictionary and return it.
- Build the flask application using the following command.
Python3
if __name__ == '__main__': app.run(debug=True) |
- Run the ‘main.py’ file in the terminal or the IDE and type the following URL in the browser.
http://127.0.0.1:5000/hello
Code :
Python3
from flask import Flask, jsonify, request app = Flask(__name__) @app.route('/hello', methods=['GET']) def helloworld(): if(request.method == 'GET'): data = {"data": "Hello World"} return jsonify(data) if __name__ == '__main__': app.run(debug=True) |
Output :
Method 2: Using the flask_restful library
- Create a new python file named ‘main.py’.
- Import Flask from the flask framework.
- Import API and Resource from the ‘flask_restful’ library.
- Register the web app into a app variable using the following syntax.
Python3
app = Flask(__name__) |
- Register the app variable as an API object using the Api method of the ‘flask_restful’ library.
Python3
api = Api(app) |
- Create a resource class named ‘HelloWorld’.
- Inside the resource class, create a ‘get’ method.
- Return a dictionary with the ‘Hello World’ message from the ‘get’ method.
- Add the resource class to the API using the add_resource method.
- Build the flask application using the following command.
Python3
if __name__ == '__main__': app.run(debug=True) |
- Run the ‘main.py’ file in the terminal or the IDE and type the following URL in the browser.
http://127.0.0.1:5000/hello
Code :
Python3
from flask import Flask from flask_restful import Api, Resource app = Flask(__name__) api = Api(app) class HelloWorld(Resource): def get(self): data={"data":"Hello World"} return data api.add_resource(HelloWorld,'/hello') if __name__=='__main__': app.run(debug=True) |
Output :
