PHP Filters

PHP Filters Tutorial

PHP filters are used to validate and sanitize user input. Filters ensure that the data received from users is safe and in the expected format, preventing errors or security vulnerabilities.

 Types of Filters

Using filter_var()

The filter_var() function validates or sanitizes a single variable.

Syntax:

a) Validate Email

b) Validate URL

c) Validate Integer

Optional Range Check:

d) Sanitize String

Note: FILTER_SANITIZE_STRING removes HTML tags and special characters.

e) Sanitize Email

f) Sanitize URL

 Using filter_input()

filter_input() validates or sanitizes form input or query parameters directly.

• INPUT_GET, INPUT_POST, INPUT_COOKIE, INPUT_SERVER, INPUT_ENV are possible sources.

 Key Points

1. Validation filters → check if data is correct.

2. Sanitization filters → clean data for safe use.

3. filter_var() → works on single variable.

4. filter_input() → works on input sources like POST/GET.

5. Always validate and sanitize user input to prevent security issues.