What are the considerations when deciding whether or not to sanitize input data in PHP?

When deciding whether or not to sanitize input data in PHP, it is important to consider the source of the data and how it will be used. If the input is coming from a trusted source and will not be directly output to the user, sanitizing may not be necessary. However, if the input is coming from an untrusted source or will be displayed on a webpage, it is crucial to sanitize the data to prevent security vulnerabilities such as SQL injection or cross-site scripting attacks. 

// Example of sanitizing input data in PHP
$input = $_POST['user_input'];
$clean_input = filter_var($input, FILTER_SANITIZE_STRING);

Keywords

SQL injection cross-site scripting filter_input htmlentities validation

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