Front End Form Special Characters Validation

• MTYsquared

• September 23, 2021 at 3:18 am

Hi guys,

I have a front end form that allow a few fie uploads. At the moment when a user uploads a file with a special character in the file name it causes an error 500 to trigger.

I am looking to validate that the filename doesnt include any special characters prior to allowing the form to submit and allow the upload but am stuck.

I have used the acf/validate_attachment hook but no luck. It works when using the example and posts the error but cant get it to work to check the filename for special characters.

Code I have so far:

add_filter('acf/validate_attachment', 'my_acf_validate_attachment', 10, 5);
function my_acf_validate_attachment( $errors, $file, $attachment, $field, $context ){

if( preg_match('/[\'^£$%&*()}{@#~?><>,|=_+¬-]/', $attachment['name']) ) {
$errors[] = __( 'File name must begin with "acf-"' );
}
return $errors;
}

Any help would be much appreciated.

• John Huebner

• September 23, 2021 at 9:03 am

I don’t know if this is the cause, but your expression could be causing issues. many of the characters you are searching for need to be escaped

preg_match('/[\'^£\$%&\*\(\)\}\{@#~\?><>,\|\=_\+¬-]/', $attachment['name']) )