# Using the validate Argument

There are many validation options included within Redux that can apply to fields. You can also build your own validations. A validation is basically a way to validate the data is correct. If the validation does not pass, a warning or error will be displayed and the changed value will not be saved.

# How to Use

You declare the use of a validation by passing the validate argument to the field array. Below is an example:

array(
    'validate' => 'not_empty'
)

# Multiple Validations

You can also have multiple validations occur on a given field by setting an array of validations. The validations will occur in the order as they appear in the array. An example of this is below.

array(
    'validate' => array( 'numeric', 'not_empty' )
)

Be warned, not all validations may chain together. Be careful and make sure you are passing any additional arugments needed.

# Using a Custom Validation

You can declare your own custom validation by providing a callback function. An example of this can be seen below.

array(
    'validate_callback' => 'test_custom_callback'
)

The function you set can do anything. Here is an example:

if ( ! function_exists( 'test_custom_callback' ) ) {
	/**
	 * Custom function for the callback validation referenced above
	 *
	 * @param array $field          Field array.
	 * @param mixed $value          New value.
	 * @param mixed $existing_value Existing value.
	 *
	 * @return mixed
	 */
	function test_custom_callback( $field, $value, $existing_value ) {
		$error   = false;
		$warning = false;

		// Do your validation.
		if ( 1 === $value ) {
			$error = true;
			$value = $existing_value;
		} elseif ( 2 === $value ) {
			$warning = true;
			$value   = $existing_value;
		}

		$return['value'] = $value;

		if ( true === $error ) {
			$field['msg']    = 'your custom error message';
			$return['error'] = $field;
		}

		if ( true === $warning ) {
			$field['msg']      = 'your custom warning message';
			$return['warning'] = $field;
		}

		return $return;
	}
}

TIP

Anything you pass back in the return object $return['value'] will be saved. You can display a warning or an error attached to the field by specifying warning or error in the return array.

# Built-in Validations

Key
Description
color Valid HTML hex color. Works with color_rgba field (opacity)
comma_numeric Value is numeric separated by commas
css CSS
date Date
email Valid Email
html_custom HTML validation - See html_custom example
js JavaScript
no_html No HTML is permitted
no_special_chars Alpha Numeric, excluding special characters
not_empty If the value is empty
numeric Value is numeric
preg_replace Perform a replace on the contents based on a regex pattern. See preg_replace Example
str_replace Return a string after running through a str_replace. See str_replace Example
unique_slug To generate a unique slug - optional 'flush_permalinks' => true argument can be added to force a flush permalinks on successful save
url Valid URL

# preg_replace Example

'preg' => array(
    'pattern' => '/[^a-zA-Z_ -]/s', 
    'replacement' => 'no numbers'
)

# str_replace Example

'validate' => 'str_replace',
'str' => array(
    'search' => ' ', 
    'replacement' => 'thisisaspace'
)

# html_custom Example

You can easily set what HTML is allowed in one of your fields by using the code below. This utilizes wp_kses from the WordPress core. You can find more information about function at http://codex.wordpress.org/Function_Reference/wp_kses

'validate'     => 'html_custom',
'allowed_html' => array( 
    'a'        => array( 
        'href'    => array(), 
        'title'   => array() 
    ), 
    'br'       => array(), 
    'em'       => array(), 
    'strong'   => array() 
)

# A Warning

WARNING

The following fields do NOT accept validation unless using validate_callback.

There may be others yet to be documented.