Is there a way to upload an image before checkout completion without a plugin?

Question

I have this plugin I've made for uploading an image before an order can be completed, but for the life of me I can't get the image to upload. $_FILES will always return nothing, I'm not sure why though. I'd like it to be that the checkout won't be completed until the image is uploaded, is this even possible? *I've been told that woocommerce uses ajax for the cart

<?php
    /*
        @package            UploadTest
        @wordpress_plugin
        Plugin Name:            UploadTest
        Plugin URI:             null
        Description:            
        Author:                 Goodship
        Version:                0.0.2
        Author URI:             www.Goodship.co.za
    */

    function add_image(){
        $testLog = fopen(plugin_dir_path( __FILE__ )."testicle.txt","w") or exit ("Unable to open file!");
        //if they DID upload a file...
        if($_FILES['testUpload']['name']){
            //if no errors...
            if(!$_FILES['testUpload']['error']){
                //now is the time to modify the future file name and validate the file
                $new_file_name = strtolower($_FILES['testUpload']['tmp_name']); //rename file
                if($_FILES['testUpload']['size'] > (1024000)) //can't be larger than 1 MB
                {
                    $valid_file = false;
                    $message = 'Oops!  Your file\'s size is to large.';
                }

                //if the file has passed the test
                if($valid_file){
                    //move it to where we want it to be
                    move_uploaded_file($_FILES['testUpload']['tmp_name'], plugin_dir_path( __FILE__ ).'uploads/'.$new_file_name);
                    $message = 'Congratulations!  Your file was accepted.';
                }
            }
            //if there is an error...
            else
            {
                //set that to be the returned message
                $message = 'Ooops!  Your upload triggered the following error:  '.$_FILES['testUpload']['error'];
            }
        }
        fwrite ($testLog ,$message);
        fwrite ($testLog ,var_dump($_FILES));
        fclose ($testLog);
    }

    add_action( 'woocommerce_checkout_update_order_meta', 'add_image');


    function add_checkout_notice() {
        echo    '<input type="file" name="testUpload" />';
    }
    add_action( 'woocommerce_checkout_before_customer_details', 'add_checkout_notice');

    ?>

Answer 1

Woocommerce checkout will always happens via Ajax ( I am not sure from what version it's been like this )

PLUGIN-DIR/woocommerce/assets/frontend/checkout.js this is the file which is responsible for the checkout action.

So uploading files from checkout page is not possible unless you intended to modify the checkout.js file by yourself.

If you still prefer uploading file from checkout page, you may refer this answer.

Answer 2

You need to call below function in your child theme.

function add_image($order_id){
  // Do your code of upload image.
} 
add_action( 'woocommerce_checkout_order_processed', 'add_image',  1, 1  );