wp_kses_check_attr_val

函数
wp_kses_check_attr_val ( $value, $vless, $checkname, $checkvalue )
参数
  • (string) $value Attribute value.
    Required:
  • (string) $vless Whether the attribute is valueless. Use 'y' or 'n'.
    Required:
  • (string) $checkname What $checkvalue is checking for.
    Required:
  • (mixed) $checkvalue What constraint the value should pass.
    Required:
返回值
  • (bool) Whether check passes.
定义位置
相关方法
wp_kses_one_attrwp_kses_attrwp_kses_attr_parsewp_kses_hairwp_kses_attr_check
引入
1.0.0
弃用
-

wp_kses_check_attr_val: 这个函数用来检查一个给定的属性值是否被允许。

对属性值进行不同的检查。

目前实现的检查是””maxlen””,””minlen””,””maxval””,””minval””和””valueless””。

function wp_kses_check_attr_val( $value, $vless, $checkname, $checkvalue ) {
	$ok = true;

	switch ( strtolower( $checkname ) ) {
		case 'maxlen':
			/*
			 * The maxlen check makes sure that the attribute value has a length not
			 * greater than the given value. This can be used to avoid Buffer Overflows
			 * in WWW clients and various Internet servers.
			 */

			if ( strlen( $value ) > $checkvalue ) {
				$ok = false;
			}
			break;

		case 'minlen':
			/*
			 * The minlen check makes sure that the attribute value has a length not
			 * smaller than the given value.
			 */

			if ( strlen( $value ) < $checkvalue ) {
				$ok = false;
			}
			break;

		case 'maxval':
			/*
			 * The maxval check does two things: it checks that the attribute value is
			 * an integer from 0 and up, without an excessive amount of zeroes or
			 * whitespace (to avoid Buffer Overflows). It also checks that the attribute
			 * value is not greater than the given value.
			 * This check can be used to avoid Denial of Service attacks.
			 */

			if ( ! preg_match( '/^s{0,6}[0-9]{1,6}s{0,6}$/', $value ) ) {
				$ok = false;
			}
			if ( $value > $checkvalue ) {
				$ok = false;
			}
			break;

		case 'minval':
			/*
			 * The minval check makes sure that the attribute value is a positive integer,
			 * and that it is not smaller than the given value.
			 */

			if ( ! preg_match( '/^s{0,6}[0-9]{1,6}s{0,6}$/', $value ) ) {
				$ok = false;
			}
			if ( $value < $checkvalue ) {
				$ok = false;
			}
			break;

		case 'valueless':
			/*
			 * The valueless check makes sure if the attribute has a value
			 * (like `<a href="blah">`) or not (`<option selected>`). If the given value
			 * is a "y" or a "Y", the attribute must not have a value.
			 * If the given value is an "n" or an "N", the attribute must have a value.
			 */

			if ( strtolower( $checkvalue ) != $vless ) {
				$ok = false;
			}
			break;

		case 'values':
			/*
			 * The values check is used when you want to make sure that the attribute
			 * has one of the given values.
			 */

			if ( false === array_search( strtolower( $value ), $checkvalue, true ) ) {
				$ok = false;
			}
			break;

		case 'value_callback':
			/*
			 * The value_callback check is used when you want to make sure that the attribute
			 * value is accepted by the callback function.
			 */

			if ( ! call_user_func( $checkvalue, $value ) ) {
				$ok = false;
			}
			break;
	} // End switch.

	return $ok;
}

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