How to Prevent Duplicate Requests with HTMX in Django Forms

Learn how to efficiently handle multiple requests with `HTMX` in Django forms by implementing redirection logic to avoid duplicate submissions.
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This video is based on the question https://stackoverflow.com/q/77864254/ asked by the user 'Isaac Fritsch' ( https://stackoverflow.com/u/19629783/ ) and on the answer https://stackoverflow.com/a/77867469/ provided by the user 'McPherson' ( https://stackoverflow.com/u/16774936/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions.

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How to Prevent Duplicate Requests with HTMX in Django Forms

When working with forms in Django, especially when using libraries like HTMX, it’s common to encounter issues with duplicate requests being sent upon form submission. This post will guide you through a common scenario involving a submit button configured with HTMX, and provide a clear solution to ensure that both the form submission and other updates, like refreshing a navigation bar, are handled seamlessly without redundancy.

The Challenge: Duplicate Requests with HTMX

In the situation described, a form submission button is set up to perform two actions:

Submit the form data (via hx-post).

Trigger a GET request to refresh the navbar (using hx-get) upon the form's submission.

When the button includes both hx-get and hx-trigger set to submit, it ends up submitting the form twice, leading to a potential duplication of requests. Conversely, omitting the hx-trigger results in only executing the GET request without submitting the form. The goal is to run both actions smoothly after form submission without triggering a duplicate request.

Existing Code Example

To illustrate the problem, here’s a simplified example of the code you might be using:

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

The Solution: Using Hx-Redirect for Efficient Handling

Fortunately, you don’t need to struggle with the potential for duplicate requests. Instead, you can implement a more streamlined approach by modifying your redirect logic after successful form submission. Here’s how to do it:

Step 1: Modify the View Logic

In your Django view handling the login (e.g., user_login), adjust the logic post-authentication to include a header that signals a redirect. Here’s an updated example of the view:

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

Step 2: Understand the Hx-Redirect Header

By adding the Hx-Redirect header, you instruct HTMX on the frontend to handle a page redirection accordingly. When the user logs in successfully, instead of returning a standard HttpResponse, your code sends back an Hx-Redirect, which efficiently manages what happens next in the browser without duplicating requests.

Conclusion

By implementing the Hx-Redirect header after successful form submission, you ensure that only one action is executed after logging in—redirecting the user to the requested page without executing the hx-get on the button. This approach not only simplifies your code but also enhances the user experience by eliminating potential issues with duplicate submissions.

Now, you can focus on more important aspects of your application, secure in the knowledge that your form submissions with HTMX in Django are both efficient and effective.

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