How to Easily Pass Data from Flask to React and Render Multiple Images Dynamically

Описание: Learn how to pass a list of images from Flask to a React application and render them dynamically in your HTML template. This guide includes easy-to-follow examples and code snippets.
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How to Easily Pass Data from Flask to React and Render Multiple Images Dynamically

When working with Flask and React, one common requirement is to send data from your Flask backend to your React frontend. A popular scenario involves sending images or plots to be displayed dynamically on a webpage. In this post, we'll tackle the problem of passing a list of images from a Flask application to a React application and rendering them in the HTML.

Understanding the Problem

In our Flask application, we want to return multiple images (for example, plots generated on the server) to be displayed on a webpage. Initially, we used a single image, which worked perfectly, but now we want to scale that by handling a list of images instead.

Current Setup

Here's the existing structure of your Flask route and HTML template:

app.py

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

liveplotframe.html

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

In this setup, liveclass.get_plot() returns a single image encoded in base64. Now, you want to modify this so that you can return a list of images.

The Proposed Solution

To achieve this transformation, we need to modify both our Flask route and the HTML template accordingly, allowing it to loop over the list of images and render each one.

Step 1: Modify the Flask Route

You will start by updating the route in your Flask app to fetch a list of images:

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

In this code, we assume liveclass.get_plots() returns a list of images encoded in base64.

Step 2: Update the HTML Template

Now it's time to modify the HTML template to dynamically render each image. Here’s how you can do it:

Updated liveplotframe.html

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

Breakdown of the Template Update

Looping with Jinja2: We've introduced a Jinja2 loop ({% for image in list_of_images %}) that allows us to iterate over list_of_images, rendering an <img> tag for each image in the list.

Dynamic Rendering: Each image is inserted in the src attribute of <img> tag using {{image}}, which ensures that all images are displayed properly on your webpage.

Conclusion

By implementing the above modifications, you will be able to pass a list of images from your Flask backend to your React frontend and render them dynamically on your webpage. This approach enhances the flexibility of your application, allowing for richer data presentation and improved user experience.

With just a few simple changes, you've set up a more dynamic method of displaying content. So go ahead, give it a try, and see how effortless it can be to bridge Flask and React in your projects!