pods_api_post_save_pod_item_{pod} hook example

gistfile1.php

<?php
/**
 * Filter the Pods saving process and run actions / modify values
 *
 * @param array $pieces An array of different variables you can *change*, see below
 *
 * List of $pieces variables includes:
 *
 * array $pieces['fields'] An array of fields on the Pod, 'value' key stores the *new* value if it's been set to save
 *
 * object $pieces['params'] An object of parameters sent to PodsAPI::save_pod_item
 *
 * array $pieces['pod'] An array of information about the Pod, like id, name, label, etc
 *
 * array $pieces['fields_active'] An array of fields that are currently being saved,
 *        you must add a new value to this array to have Pods save it, or remove it to not have it save
 *
 * array $pieces['object_fields'] An array of the WP Object fields for the Pod (WP-based content types)
 *
 * array $pieces['custom_fields'] An array of the custom fields (ones that aren't actually fields on the Pod)
 *        being saved, this cannot be changed (meta-based content types)
 *
 * array $pieces['custom_data'] An array of the custom field values being saved, you can change this to add
 *        other custom fields to the saving process (meta-based content types)
 */
function my_pod_essay_save( $pieces ) {

	$fields = $pieces[ 'fields' ];

	if ( !empty( $fields[ 'wp_post_id' ][ 'value' ] ) ) {
		// Create update post object
		$updated_post = array();

		$updated_post[ 'ID' ] = $fields[ 'wp_post_id' ][ 'value' ];
		$updated_post[ 'post_date' ] = $fields[ 'date' ][ 'value' ];

		//if this is a ya essay, add the ya category
		if ( empty( $fields[ 'ya_essay' ][ 'value' ] ) ) {
			// Insert category "Essay"
			$updated_post[ 'post_category' ] = array( 63 );
		}
		else {
			$updated_post[ 'post_category' ] = array( 63, 203 );
		}

		// Update the post into the database
		wp_update_post( $updated_post );
	}

	// The pre-save filter allows you to change values, you must return $pieces
	return $pieces;

}

add_filter( 'pods_api_post_save_pod_item_my_pod_essay', 'my_pod_essay_save' );

// Also consider using post_save instead, it's an action and is only run on a successful save (after validation, etc)
// add_action( 'pods_api_pre_save_pod_item_my_pod_essay', 'my_pod_essay_save' );