Advanced Custom Fields Validation

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Is there way to use custom validation on an advanced custom field? For example, I might not want a textfield to have a value that starts with certain prefix, or I might want a number field to have a value greater than ‘x’. I might also want to run a regex against a value and return an error if it doesn’t match.

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  2. I did it by plugging into acf/pre_save_post. Using that, you can test the $_POST data. And if you don’t like something, you can change $post_id to “error” when you return it. This will keep the form from processing since the post_id is not correct. You can also plug in to acf/save_post to make sure to unset the “return” or update messages from the form.

    It is all a little complicated, but I will try to give a simplified example of what I used.

    $submitted_fields = '';
$validation_errors = '';

add_filter( 'acf/pre_save_post', 'custom_validation' );
function custom_validation( $post_id )
{
    // Load the fields from $_POST
    if ( empty($_POST['fields']) || ! is_array($_POST['fields']) )
    {
        $validation_errors['empty'] = "One or more fields below are required";
    }
    else
    {
        foreach( $_POST['fields'] as $k => $v )
        {
            // get field
            $f = apply_filters('acf/load_field', false, $k );
            $f['value'] = $v;
            $submitted_fields[$f['name']] = $f;
        }
    }

    // Test stuff...
    if ( empty($submitted_fields['foo']) || 'bar' != $submitted_fields['foo'] )
    {
        $validation_errors['foo'] = "Foo did not equal bar";
    }

    // If there are errors, output them, keep the form from processing, and remove any redirect
    if ( $validation_errors )
    {
        // Output the messges area on the form
        add_filter( 'acf/get_post_id', array(__CLASS__, 'add_error') );
        // Turn the post_id into an error
        $post_id = 'error';
        // Add submitted values to fields
        add_action('acf/create_fields', array(__CLASS__, 'acf_create_fields'), 10, 2 );
    }
    else
    {
        // Do something... do nothing... ?
    }

    // return the new ID
    return $post_id;
}

    function acf_create_fields( $fields, $post_id )
    {
        foreach ( $fields as &$field )
        {
            if ( array_key_exists($field['name'], $submitted_fields) )
                $field['value'] = $submitted_fields[$field['name']];
        }
        return $fields;
    }

    function add_error()
    {
        echo '<div id="message" class="error">';
        foreach ( $validation_errors as $key => $error )
        {
            echo '<p class="' . $key . '">' . $error . '</p>';
        }
        echo '</div>';
    }

add_action('acf/save_post', 'custom_handle_error', 1);
function custom_handle_error( $post_id )
{
    if ( 'error' == $post_id )
    {
        unset($_POST['return']);
    }
}

    This doesn’t allow to highlight fields that returned an error, but you could actually do it pretty easily with javascript using the classes from the errors in #message div.

  4. you can use this code

    add_filter('acf/validate_value/name=validate_this_image', 'my_acf_validate_value', 10, 4);

function my_acf_validate_value( $valid, $value, $field, $input ){

// bail early if value is already invalid
if( !$valid ) {

    return $valid;

}


// load image data
$data = wp_get_attachment_image_src( $value, 'full' );
$width = $data[1];
$height = $data[2];

if( $width < 960 ) {

    $valid = 'Image must be at least 960px wide';

}


// return
return $valid;


}

    result
    enter image description here
    Documentation