JSON request parsing in Flask - Mini Project: Build & Apply

JSON Request Parsing with Flask

📖 Scenario: You are building a simple web service that receives user data in JSON format. The service will read the JSON data sent in a POST request and extract specific information.

🎯 Goal: Create a Flask app that parses JSON data from a POST request and extracts the user's name and age.

📋 What You'll Learn

Create a Flask app instance named app

Define a route /user that accepts POST requests

Parse JSON data from the request using request.get_json()

Extract name and age from the JSON data

Return a simple string response confirming the received data

💡 Why This Matters

🌍 Real World

Web APIs often receive data in JSON format from clients. Parsing JSON requests is essential to handle user input or data submissions.

💼 Career

Backend developers frequently build REST APIs using Flask or similar frameworks that require JSON parsing to process client data.

1

Set up Flask app and import modules

Write the code to import Flask and request from flask. Then create a Flask app instance called app.

Flask

from flask import Flask, request

# Create Flask app instance called app
# Your code here

Need a hint?

Use from flask import Flask, request and then app = Flask(__name__).

2

Create POST route to receive JSON

Define a route /user on app that accepts POST requests only. Use the decorator @app.route('/user', methods=['POST']).

Flask

from flask import Flask, request

app = Flask(__name__)

# Define POST route '/user'
# Your code here

Need a hint?

Use @app.route('/user', methods=['POST']) and define a function user().

3

Parse JSON data from request

Inside the user function, get the JSON data from the request using data = request.get_json(). Then extract name and age from data.

Flask

from flask import Flask, request

app = Flask(__name__)

@app.route('/user', methods=['POST'])
def user():
    # Get JSON data from request
    # Extract 'name' and 'age' from data
    # Your code here

Need a hint?

Use data = request.get_json() then name = data['name'] and age = data['age'].

4

Return confirmation string with extracted data

Return a string from the user function that says Received user: {name}, age {age} using an f-string.

Flask

from flask import Flask, request

app = Flask(__name__)

@app.route('/user', methods=['POST'])
def user():
    data = request.get_json()
    name = data['name']
    age = data['age']
    # Return confirmation string
    # Your code here

Need a hint?

Use return f"Received user: {name}, age {age}" to send back the confirmation.