gistfile1.php

<?php

class Filter
{
  const REGEX_TRIM = "[\\x0-\x20\x7f]";
  const REGEX_FTRIM = "[\\x0-\x20\x7f\xc2\xa0\xe3\x80\x80]";

  public static function presetUtf8($default = '')
  {
    return function($tainted) use ($default)
    {
      if (!is_scalar($tainted))
        return $default;

      return preg_replace('//u', '', $tainted) ?: $default;
    };
  }

  public static function presetTrim()
  {
    return function($tainted)
    {
      if (!is_scalar($tainted))
        return '';

      return preg_replace(sprintf('/\A%1$s++|%1$s++\z/u', Filter::REGEX_TRIM), '', $tainted) ?: '';
    };
  }

  public static function presetFullTrim()
  {
    return function($tainted)
    {
      if (!is_scalar($tainted))
        return '';

      return preg_replace(sprintf('/\A%1$s++|%1$s++\z/u', Filter::REGEX_FTRIM), '', $tainted) ?: '';
    };
  }

  public static function presetRecursive(Closure $filter)
  {
    return function($taintedArray) use ($filter)
    {
      $clean = array();
      foreach ((array)$taintedArray as $key => $taintedValue)
      {
        if (!preg_match('//u', $key))
          continue;

        $clean[$key] = $filter($taintedValue);
      }
      return $clean;
    };
  }

  public static function schema(array $schema)
  {
    foreach ($schema as $key => &$value)
    {
      if (is_scalar($value))
        $value = self::presetUtf8($value);
    }

    return function($taintedArray) use ($schema)
    {
      $clean = array();
      foreach ($schema as $key => $filter)
      {
        $tainted = isset($taintedArray[$key]) ? $taintedArray[$key] : null;
        $clean[$key] = $filter($tainted);
      }
      return $clean;
    };
  }
}  
  
$filterDef = array(  
  'name' => '',  
  'age' => Filter::presetTrim(),  
  'email' => '',  
  'gender' => Filter::presetTrim(),  
  'comment' => '',  
  'options' => Filter::presetRecursive(Filter::presetFullTrim()),  
  'date' => function($tainted) {  
    return is_string($tainted) && preg_match('/^\d{4}-\d{2}-\d{2}$/u', $tainted)  
        ? $tainted  
        : '';  
  },  
);  
$filter = Filter::schema($filterDef);  

// 入力値
$tainted = array(
  'name' => array('INVALID' => 'これは無効な値です'),
  'age' => ' 20 ',
  'gender' => '   male 　　　　', 
  'comment' => '　はじめまして！！　　　　',
  'options' => array(
    'a' => ' 　yes　',
    'b' => "\x0a\x0a\xff",
    'c' => array('INVALID' => 'これは無効な値です'),
    "\x0a\x0a\xff" => 'INVALID',
  ),
  'date' => '2014-02-16',
);
$cleanValue = $filter($tainted);

var_dump($cleanValue);

/*
結果:
  array(7) {
    'name' =>
    string(0) ""
    'age' =>
    string(2) "20"
    'email' =>
    string(0) ""
    'gender' =>
    string(17) "male 　　　　"
    'comment' =>
    string(39) "　はじめまして！！　　　　"
    'options' =>
    array(3) {
      'a' =>
      string(3) "yes"
      'b' =>
      string(0) ""
      'c' =>
      string(0) ""
    }
    'date' =>
    string(10) "2014-02-16"
  }
*/