How to Display/Edit an ActiveStorage S3 Image in React with Dropzone

Learn how to efficiently display and edit ActiveStorage S3 images in your React app. Discover step-by-step guidance on using Dropzone for seamless image handling.
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How to Display/Edit an ActiveStorage S3 Image in React with Dropzone

If you're working with Ruby on Rails combined with React for building a web application, you might face some challenges when dealing with image uploads and edits. This is especially true when you're using ActiveStorage to manage images uploaded to an S3 bucket. In this guide, we will discuss how to display and edit those images in a React application using the Dropzone library effectively.

The Problem

You have a form where users can upload images via Dropzone, and you're able to store those images in S3 successfully using ActiveStorage. However, when it comes to editing, you want to be able to display the previously uploaded images within the same Dropzone uploader for users to decide if they want to replace them or not. This raises the question: How can you show existing images and handle the uploading of new files using React and Dropzone?

The Solution

Step 1: Get the S3 Object URL

To begin, the key to displaying existing images is to retrieve their URLs from the S3 bucket. You can do this directly in your Rails view. Here's a simple example of how to accomplish that in your edit.html.erb file:

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In the HTML above, we're using url_for(record.image) to fetch the URL of the existing S3 image and display it as a standard image element. This lets users see what image is currently uploaded.

Step 2: Setup the Dropzone Form

Once the existing image is displayed, you can place the Dropzone upload form beneath it. This arrangement helps guide the users by indicating that the form can be used to replace the existing image. Here's a basic example of how you might set it up:

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

Step 3: Attach New Image in the Update Action

Now that the user has the option to see the existing image and replace it if they choose to, you will need to ensure that the new image is handled properly. When the form is submitted, you can retrieve the new image file using the update action in your controller. Here's a simplified version of how this might look:

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

Conclusion

Implementing image upload and editing functionality using Ruby on Rails with React and Dropzone may initially seem daunting, but with the right steps, it can be straightforward. By displaying the existing image using its S3 URL and leveraging Dropzone for new uploads, you can create a seamless experience for your users. Follow the steps outlined above, and you’ll be well on your way to perfecting your image handling capabilities!

Feel free to ask if you have any questions or need further clarification on any of the steps. Happy coding!