How to Prevent Multiple Form Submissions and Ensure Data Integrity in PHP?

Preventing Multiple Inserts on Form Submission in PHP

In PHP form submissions, it is not uncommon to encounter situations where users may accidentally submit the form multiple times, leading to duplicate insertions in the database. There are various approaches to address this issue other than checking for existing records with identical titles and content. This article explores three reliable solutions:

Disabling Form Submission Button

Utilizing JavaScript to disable the form's submit button upon submission is a possible solution. This approach, however, has significant limitations as it is not foolproof. Users can bypass the button and submit forms, and it may not work effectively with JavaScript disabled. This method is not recommended.

PHP Session Variables

In PHP, session variables can be used to store a session-specific timestamp ($_SESSION['posttimer']) during form submission. By validating this variable before processing the form and comparing it with the current system time, double submissions can be effectively filtered out. A timestamp difference of more than two seconds, for instance, would indicate a legitimate submission.

Unique Token Generation

Generating a unique token for each POST request is another reliable method. This involves setting a session variable with the token and embedding it within the form. On subsequent form submissions, the token is regenerated, and a mismatch between the submitted token and the stored session token would signify a double submission and prompt the form to be flagged as invalid.

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