Upload field mapping to ACF custom field

wpmudev-upload-mapping-custom-field.php

<?php
/**
 * Plugin Name: [Forminator] Upload mapping to ACF image field
 * Description: Solves a bug that prevents upload field mapping to ACF image field through post data form
 * Author: Prashant Singh @ WPMUDEV
 * Author URI: https://premium.wpmudev.org
 * License: GPLv2 or later
 */

if ( ! defined( 'ABSPATH' ) ) {
	exit;
}

if ( defined( 'WP_CLI' ) && WP_CLI ) {
	return;
}

add_filter( 'forminator_custom_form_submit_errors', 'wpmudev_map_uplods_acf_post_test', 10, 3 );
function wpmudev_map_uplods_acf_post_test( $submit_errors, $form_id, $field_data_array ) {
    $form_ids = array( 4126, 2910 ); //Please change form IDs to your form IDs
	if( !in_array( $form_id, $form_ids ) ){
		return $submit_errors;
	}

	$submitted_data = Forminator_CForm_Front_Action::$prepared_data;
	
	if( isset( $submitted_data['postdata-1'] ) && is_array( $submitted_data['postdata-1'] ) ) {
		if( isset( $submitted_data['postdata-1']['post-custom'] ) && is_array( $submitted_data['postdata-1']['post-custom'] ) ) {
			foreach( $submitted_data['postdata-1']['post-custom'] as $post_key => $post_val ) {
				if( strpos( $post_val['value'], '{upload' ) !== false ) {
					$field_name = str_replace('{', '', $post_val['value'] );
					$field_name = str_replace('}', '', $field_name );
					if ( is_array( $submitted_data[ $field_name ] ) && isset( $submitted_data[ $field_name ]['file'] ) ) {
						if ( isset( $submitted_data[ $field_name ]['file']['file_url'] ) ) {
							Forminator_CForm_Front_Action::$prepared_data['postdata-1']['post-custom'][$post_key]['value'] = $submitted_data[ $field_name ]['file']['file_url'];
						}
					}
				}
			}
		}
	}
	
	return $submit_errors;
}

add_action( 'forminator_post_data_field_post_saved', 'wpmudev_update_post_acf_uploads_test', 10, 4 );
function wpmudev_update_post_acf_uploads_test( $post_id, $field, $data, $cls ){
	$submitted_data = Forminator_CForm_Front_Action::$prepared_data;
	$form_ids = array( 4126, 2910 ); //Please change form IDs to your form IDs
	if ( !in_array( $submitted_data['form_id'], $form_ids ) ) {
	  return;  
	}
	
	if( isset( $submitted_data['postdata-1'] ) && is_array( $submitted_data['postdata-1'] ) ) {
		if( isset( $submitted_data['postdata-1']['post-custom'] ) && is_array( $submitted_data['postdata-1']['post-custom'] ) ) {
			foreach( $submitted_data['postdata-1']['post-custom'] as $post_key => $post_val ) {
				if ( $post_val['key'] == 'test_image' ) { //Please change test_image to your custom field name
				    if ( isset( $post_val['value'] ) ) {
    					$attach_id = attachment_url_to_postid( $post_val['value'] );
    					if( $attach_id ) {
    						update_field($post_val['key'], $attach_id, $post_id);
    						$mime_type = wp_get_image_mime( $post_val['value'] );
    						if( $mime_type ) {
    							$update_data = array(
    								'ID' => $attach_id,
    								'post_mime_type' => $mime_type,
    							);
    							wp_update_post( $update_data );
    						}
    					}
				    }
				}
			}
		}
	}
}