File input problem

Hi,

I am using a snippet to give the ability to logged users to post and edit specific type resources via formit.

One of the fields of the formit form is a file input that is uploading as a tv field.

The problem is that when a user updates the resource and leave the file input field blank, when it saves, the blank input overwrite any previous inputs.

All I want is to make the snippet to ignore blank inputs only at the file input field.

If anynone can help. I am really stuck here.

Below is the code I use.

<?php
if (isset($_GET['resId'])){
    if ($doc=$modx->getObject('modResource',array('id'=>$_GET['resId']))){
        $docarray=$doc->toArray();
        $fields = explode(',',$scriptProperties['resource2formitfields']);
        $fields[] = 'id';
  
        foreach ($fields as $field){
         
            if ($doc->getFieldName($field) === null) {
                /* if field isnt defined, look for TV value */
                $tvValue = $doc->getTVValue($field);
                if ($tvValue !== null) {
                    $hook->setValue($field,$tvValue);
                }
            } else {
                /* otherwise get field value */
                $hook->setValue($field,$docarray[$field]);
            }    
        }
    }
  
    //$errorMsg = '<pre>'.print_r($docarray,true).'</pre>';  
    //$hook->addError('error_message',$errorMsg);  
}
  
  
return true;

if ($tvValue !== null) {
	$hook->setValue($field,$tvValue);
}

if ($field == 'file' && !empty($tvValue)) {
	$hook->setValue($field, $tvValue);
}
else {
	$hook->setValue($field, $tvValue);
}