How to Call a Python Function on Button Click Event in Flask

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Summary: Learn how to implement a button OnClick event in Flask to trigger a Python function. This guide covers the steps to seamlessly integrate frontend interactions with backend functionality in your Flask web applications.
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Flask, a popular web framework for Python, provides a straightforward way to build web applications. While creating interactive web pages, you may encounter scenarios where you need to call a Python function when a button is clicked. In this guide, we'll explore the steps to achieve this in a Flask application.

Setting up your Flask App

Firstly, make sure you have Flask installed. If not, you can install it using:

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

Now, let's create a simple Flask application with a button that triggers a Python function.

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

Creating the HTML Template

Next, create an index.html file in a folder named templates. This folder should be in the same directory as your main application file. Add the following code to create a button in the HTML file:

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

Handling the Button Click in Flask

Now, let's modify the Flask application to handle the button click. Update the main application file as follows:

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

Explanation

The index.html file includes a button with an onclick attribute that calls the callPythonFunction JavaScript function.

In the JavaScript function, a fetch request is made to the Flask route /button_click.

The Flask route /button_click is updated to handle the button click. It then calls the Python function, and the result is returned as JSON.

By following these steps, you can seamlessly integrate button click events with Python functions in your Flask application. This approach allows you to create dynamic and interactive web applications using the Flask framework.