Filter or Sanitizer?

1-FilterOrSanitizer.md

• A filter removes unwanted data.
• A sanitizer modifies data according to a standard or specification.

See FilterIterator

FilterInterface.php

<?php

/**
 * A filter removes unwanted data.
 */
interface FilterInterface
{
    /**
     * Filter the data
     * 
     * @param mixed $data the data to filter [implied]
     * @return mixed
     */
    function filter();
}

RegexFilter.php

<?php

/**
 * Remove strings matching a regex pattern.
 */
class RegexFilter implements FilterInterface
{
    /**
     * @var string|array
     */
    private $pattern;
    
    /**
     * @var integer
     */
    private $limit;
    
    
    /**
     * Constructor
     * 
     * @param string|array $pattern the regex pattern(s)
     * @param integer      $limit   the maximum possible replacements for each pattern
     */
    public function __construct($pattern, $limit = -1)
    {
        $this->pattern = $pattern;
        $this->limit   = $limit;
    }
    
    /**
     * Filter a string by the pattern
     * 
     * @param string $string the string to filter
     * @return string|null
     */
    public function filter($string)
    {
        return preg_replace($this->pattern, '', $string, $this->limit);
    }
}

RegexSanitizer.php

<?php

/**
 * Replace regex matches in strings
 */
class RegexSanitizer implements SanitizerInterface
{
    /**
     * @var string|array
     */
    private $pattern;
    
    /**
     * @var string|array
     */
    private $replacement;
    
    /**
     * @var integer
     */
    private $limit;
    
    
    /**
     * Constructor
     * 
     * @param string|array $pattern     the regex pattern(s)
     * @param string|array $replacement the replacement(s)
     * @param integer      $limit       the maximum possible replacements for each pattern
     */
    public function __construct($pattern, $replacement, $limit = -1)
    {
        $this->pattern     = $pattern;
        $this->replacement = $replacement;
        $this->limit       = $limit;
    }
    
    /**
     * Sanitize a string by the pattern
     * 
     * @param string $string the string to sanitize
     * @return string
     */
    public function sanitize($string)
    {
        return preg_replace($this->pattern, $this->replacement, $string, $this->limit);
    }
}

SanitizerInterface.php

<?php

/**
 * A sanitizer modifies data according to a standard or specification.
 */
interface SanitizerInterface
{
    /**
     * Sanitize the data
     *
     * @param mixed $data the data to sanitize [implied]
     * @return mixed
     */
    function sanitize();
}