Forms and User Input in PHP
Forms and user input are how PHP websites get data from their users. This section covers how PHP manages form data, checks it for validity and protects the website. Forms are the foundation of many real world PHP applications.
What You Will Learn in This Tutorial
In this unit you will learn how the PHP script receives the data from the HTML form. You will also learn how to process this data safely and correctly. By the end of this unit you will know how to do 99% of tasks with forms in PHP.
HTML Forms Basics
HTML takes the information submitted from the user using input fields. While on the server, PHP can process this information.
Example
<form method="post" action="process.php">
<input type="text" name="username">
<input type="submit">
</form>
GET Method in PHP Forms
GET Method, sends form data as URL arguments, so it can be shown in the browser. Good for search forms and not sensitive data.
Example
<?php
echo $_GET["username"];
?>
POST Method in PHP Forms
POST is the method used to submit form data in the request body securely. Developers use it for login forms and other forms where information needs to be kept private.
Example
<?php
echo $_POST["username"];
?>
Accessing Form Data in PHP
PHP saves the form values in superglobal arrays. So superglobal arrays makes easy to access user input.
Common superglobals
• $_GET
• $_POST
• $_REQUEST
Validating User Input in PHP
Input validation, this check the entered data is valid. There are numerous validation around in PHP like empty field, data type, format of data etc.
Example
<?php
if (empty($_POST["email"])) {
echo "Email is required";
}
?>
Sanitizing User Input in PHP
Sanitizing releases unwanted characters and would make your program more secure. Well, it is the best security that can be added into the system.
Example
<?php
$email = filter_input(INPUT_POST, "email", FILTER_SANITIZE_EMAIL);
?>
Error Handling in Form
Error handling can also make a form more user friendly. PHP provides a way to display helpful message to the user if validation errors occur.
Securing Forms from Attacks
PHP form processing should be secure from the most simple common attacks such as XSS and SQL injection. These are some common security techniques.
Practical Examples
This includes few examples such as
• Login forms
• Contact forms
• Registration forms
• Feedback forms/ questionaires
Conclusion
Forms and user input management is fundamental to PHP programming. This module will show you how to gather, validate and protect user input using PHP. Good form, handling skills are essential for creating solid PHP applications.
