How to allow .xls file uploads?

Question

I am getting the following error when trying to upload a xls file.

Sorry, this file type is not permitted for security reasons.

Tried plugin wp-extra file type and there is no option to choose an xls file type.

tried pro mime type plugin, there is an option for Xls to allow and I did it too but still not working and getting the same error.

Also tried to add the following code in a function.php

function my_myme_types($mime_types){
      // New allowed mime types.
$mime_types['xls'] = 'application/vnd.ms-excel';

return $mime_types;
}
add_filter('upload_mimes', 'my_myme_types', 1, 1);

but still showing the same error.

Also tried

function wpse294198_mime_types( $mimes ) {
    $mimes['xls|xlsx'] = 'application/vnd.ms-excel';
    return $mimes;
}
add_filter( 'mime_types', 'wpse294198_mime_types' );

the only solution worked is wp-config ALLOW UNFILTERED UPLOADS. but this is risky if we considered the security reason. I just want to allow xls file not any other file format like Php, js extra.

 define(‘ALLOW_UNFILTERED_UPLOADS’, true)

the problem I face with the above solution that now anyone can upload any type of file from anywhere if there is upload option for him. So I believe this is not a good thing. I need a better solution to my problem.

I am using WordPress v5.2 and someone suggested me to try below solution but didn't work either.

function wpse323750_multi_mimes( $check, $file, $filename, $mimes ) {
  if ( empty( $check['ext'] ) && empty( $check['type'] ) ) {
    $multi_mimes = [ [ 'xls' => 'application/excel' ], [ 'xls' => 'application/vnd.ms-excel' ], ['xls' => 'application/x-excel' ], ['xls' => 'application/x-msexcel'] ];

  foreach( $multi_mimes as $mime ) {
    remove_filter( 'wp_check_filetype_and_ext', 'wpse323750_multi_mimes', 99, 4 );
    $check = wp_check_filetype_and_ext( $file, $filename, $mime );
    add_filter( 'wp_check_filetype_and_ext', 'wpse323750_multi_mimes', 99, 4 );
    if ( ! empty( $check['ext'] ) ||  ! empty( $check['type'] ) ) {
      return $check;
    }
  }
  }
  return $check;
}
add_filter( 'wp_check_filetype_and_ext', 'wpse323750_multi_mimes', 99, 4 );

Answer 1

Try the same function but different $mime_types key ('xla|xls|xlt|xlw'):

<?php
function my_myme_types( $mime_types ){
    // New allowed mime types.
    $mime_types['xla|xls|xlt|xlw'] = 'application/vnd.ms-excel';

    return $mime_types;
}
add_filter( 'upload_mimes', 'my_myme_types', 1, 1 );

To get MIME type array keys and values used by WordPress:

<?php
$mimes = wp_get_mime_types();

echo '<pre>';
print_r( $data );
echo '</pre>';