bookmark_borderdynamic_field_map Field


The dynamic_field_map type field, part of the Settings API, allows the user to map their form fields to custom keys (fields), e.g. fields you will be sending to a third-party service such as a CRM.


The following example shows how you can allow the user to define a number of custom keys and map them to their form fields, which in this case is limited to twenty. We are also excluding the creditcard field from the drop downs which contain the form fields as choices.

	'title'  => esc_html__( 'This is the title for Section 1', 'sometextdomain' ),
	'fields' => array(
			'name'                => 'metaData',
			'label'               => esc_html__( 'Metadata', 'sometextdomain' ),
			'type'                => 'dynamic_field_map',
			'limit'               => 20,
			'exclude_field_types' => 'creditcard',
			'tooltip'             => '<h6>' . esc_html__( 'Metadata', 'sometextdomain' ) . '</h6>' . esc_html__( 'You may send custom meta information to [...]. A maximum of 20 custom keys may be sent. The key name must be 40 characters or less, and the mapped data will be truncated to 500 characters per requirements by [...]. ', 'sometextdomain' ),
			'validation_callback' => array( $this, 'validate_custom_meta' ),

The above code would render a field like the following:



In the above example a validation callback is also specified to ensure that the limit is not exceeded and that the custom keys don’t exceed the character limit defined by the third-party service.

public function validate_custom_meta( $field ) {
	//Number of keys is limited to 20 - interface should control this, validating just in case
	//key names can only be max of 40 characters

	$settings = $this->get_posted_settings();
	$metaData = $settings['metaData'];

	if ( empty( $metaData ) ) {

	//check the number of items in metadata array
	$metaCount = count( $metaData );
	if ( $metaCount > 20 ) {
		$this->set_field_error( array( esc_html__( 'You may only have 20 custom keys.' ), 'sometextdomain' ) );


	//loop through metaData and check the key name length (custom_key)
	foreach ( $metaData as $meta ) {
		if ( empty( $meta['custom_key'] ) && ! empty( $meta['value'] ) ) {
			$this->set_field_error( array( 'name' => 'metaData' ), esc_html__( "A field has been mapped to a custom key without a name. Please enter a name for the custom key, remove the metadata item, or return the corresponding drop down to 'Select a Field'.", 'sometextdomain' ) );
		} elseif ( strlen( $meta['custom_key'] ) > 40 ) {
			$this->set_field_error( array( 'name' => 'metaData' ), sprintf( esc_html__( 'The name of custom key %s is too long. Please shorten this to 40 characters or less.', 'sometextdomain' ), $meta['custom_key'] ) );


The following functions may come in helpful when interacting with the dynamic_field_map field type during feed processing.


Retrieves the individual field_map fields from the meta property of the Feed Object for the supplied field name.

$metaData = $this->get_dynamic_field_map_fields( $feed, 'metaData' );
  • $feed Feed Object

    The Entry Object to be checked.

  • $name string

    The name property of the dynamic_field_map field to retrieve the mapped fields for.

  • Returns array

    An array containing the field names or custom keys as the keys to the mapped form field ID or entry meta key.