How to Effectively Pass Input Data from ReactJS to Flask-Python Backend

Learn how to seamlessly transmit data from your ReactJS frontend to a Flask-Python backend. This guide will break down the steps for building a directory website.
---
This video is based on the question stackoverflow.com/q/69970059/ asked by the user 'mirkovski' ( stackoverflow.com/u/14514769/ ) and on the answer stackoverflow.com/a/69984860/ provided by the user 'code0x00' ( stackoverflow.com/u/16835011/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: How to pass input data from ReactJS to Flask-Python (Backend)

Also, Content (except music) licensed under CC BY-SA meta.stackexchange.com/help/licensing
The original Question post is licensed under the 'CC BY-SA 4.0' ( creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( creativecommons.org/licenses/by-sa/4.0/ ) license.

If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com.
---
How to Effectively Pass Input Data from ReactJS to Flask-Python Backend

Building a modern web application often involves pairing a frontend framework with a backend technology. If you are developing a directory website using ReactJS for the frontend and Python Flask for the backend, you might be wondering: How can I pass input data from ReactJS to Flask? This guide will walk you through the necessary steps to send data from your ReactJS component to a Flask API endpoint, and how to verify that the data was received correctly.

The Problem

Imagine you have a SearchBar component in your React application, and you want users to input keywords that can be processed by your Python Flask server. The goal is to ensure that the text inputted in your React frontend is effectively sent to your Flask backend and can be utilized for database queries or other processing tasks.

Setting Up Your React Component

Here’s a breakdown of how you can set up your SearchBar component to capture user input and send it to your backend.

Step 1: Create the SearchBar Component

This React component utilizes the useState hook to manage the state of the input field. When the user searches, the input is sent to the /ML/search endpoint in your Flask application.

[[See Video to Reveal this Text or Code Snippet]]

Key Components:

State Management: useState is used to handle the input text state.

Event Handlers: onChange updates the search term and onSearch handles the search action.

Creating the Flask API Endpoint

Next, you need to create an appropriate API endpoint in Flask that will handle the POST request and extract the data sent from the React frontend.

Step 2: Define the Endpoint

Below is a simple implementation for your Flask app that will receive the data from React.

[[See Video to Reveal this Text or Code Snippet]]

Important Notes:

Route Decorator: The -app.route decorator is used to specify the URL endpoint and allowed methods.

Data Handling: The function reads the incoming JSON request and extracts the search term.

Verifying Data Transfer

To ensure the data is being sent correctly to your Flask backend, you can add a console log statement in the onSearch function to print out the response received.

Step 3: Update the onSearch Function

Here’s the modification to the onSearch function to log the response data back to the console:

[[See Video to Reveal this Text or Code Snippet]]

Conclusion

Incorporating the above setup allows you to effectively pass input data from your React frontend to your Flask backend. By sending the text inputs through a POST request and confirming receipt in your console, you can ensure that your application is functioning as intended. Now, you can easily utilize this received data for various backend operations, such as querying your database.

Additional Tips

Error Handling: Consider adding error handling in your fetch call to manage any potential issues with the network request.

Security: Always validate and sanitize input data on the backend to prevent security vulnerabilities.

Further Reading: Look into CORS settings if you are hosting your server and client separately.

Implement these strategies to build robust and interactive web applications using ReactJS and Flask.