How to Successfully Read a POST Value in a Custom Form Control in Kentico

Discover how to read POST values in your Kentico custom form controls, especially for Google reCAPTCHA V3 tokens, ensuring proper validation before data saving. --- This video is based on the question https://stackoverflow.com/q/66425808/ asked by the user 'stuzzo' ( https://stackoverflow.com/u/320318/ ) and on the answer https://stackoverflow.com/a/66431925/ provided by the user 'Mcbeev' ( https://stackoverflow.com/u/12762/ ) at 'Stack Overflow' website. Thanks to these great users and Stackexchange community for their contributions. Visit these links for original content and any more details, such as alternate solutions, latest updates/developments on topic, comments, revision history etc. For example, the original title of the Question was: Kentico how to read a POST Value in a custom form control Also, Content (except music) licensed under CC BY-SA https://meta.stackexchange.com/help/licensing The original Question post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license, and the original Answer post is licensed under the 'CC BY-SA 4.0' ( https://creativecommons.org/licenses/by-sa/4.0/ ) license. If anything seems off to you, please feel free to write me at vlogize [AT] gmail [DOT] com. --- How to Successfully Read a POST Value in a Custom Form Control in Kentico If you're working with Kentico and you've recently added a custom form control designed to handle the Google reCAPTCHA V3 token, you may find yourself facing a common challenge: how to read the value of that POST request in your custom control. This guide will guide you step-by-step through the solution, helping you validate the token effectively before proceeding with form submission. The Problem While testing your custom form control, you may notice that the reCAPTCHA token is successfully sent from the client-side. However, retrieving that token in your code-behind to validate it can become tricky. Developers often attempt to access the token using helper functions, but it may not yield the result expected or can even lead to errors. To make this process easier, let's break down the solution into simple steps: Step 1: Use a HiddenField Control A HiddenField control is crucial because it will store the reCAPTCHA token that the JavaScript populates. You will add this hidden field in your .ascx file as follows: [[See Video to Reveal this Text or Code Snippet]] This control ensures that the token is sent back to the server with the form submission. Step 2: Retrieve the Value in Your Code-Behind Now that you have a hidden field, let’s implement how to access it in your code-behind file (.ascx.cs). You can redefine the Value property to get and set the token value, as illustrated below: [[See Video to Reveal this Text or Code Snippet]] Explanation: Get: Retrieve the token value from the HiddenField when the form is submitted. Set: Assign a token value back to the HiddenField, if necessary. Step 3: Populate the HiddenField with JavaScript Next, ensure that your JavaScript code correctly populates the hidden field whenever the reCAPTCHA challenge is successfully completed. Here’s an example of how you can do this: [[See Video to Reveal this Text or Code Snippet]] This line assigns the token retrieved from Google reCAPTCHA to the hidden field, making it available for server-side processing. Step 4: Validate the Token Now that you have the token stored, it's essential to validate it before saving any data from the form. To accomplish this, you'll override the IsValid method. Here’s a simplified version of how you can implement this: [[See Video to Reveal this Text or Code Snippet]] Token Validation Logic The actual validation occurs in the ReCaptchaCheckPassed method, which will perform an HTTP request to Google's reCAPTCHA API to verify the token: [[See Video to Reveal this Text or Code Snippet]] Explanation of Validation Logic: The method checks if the token is valid by sending it to Google's verification endpoint. It processes the HTTP response and checks if the reCAPTCHA verification succeeded. Conclusion By following these steps, you can effectively read and validate a POST value from a custom form control in Kentico, particularly for Google reCAPTCHA V3 tokens. This ensures a smoother user experience while safeguarding your form against spambots. If you encounter challenges along the way, remember that breaking down your implementation into these simpler parts often leads to easier debugging and solutions. Happy coding!