[wp-trac] [WordPress Trac] #45615: CSV Mime Type fails upload

[WordPress Trac]

#45615: CSV Mime Type fails upload
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 Reporter:  Kloon                     |       Owner:  joemcgill
     Type:  defect (bug)              |      Status:  assigned
 Priority:  normal                    |   Milestone:  5.0.3
Component:  Upload                    |     Version:  5.0.1
 Severity:  normal                    |  Resolution:
 Keywords:  has-patch has-unit-tests  |     Focuses:
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Comment (by birgire):

 As I understand it:

 If we associate a given file extension to multiple mime types in
 {{{wp_get_mime_types()}}}, then {{{wp_check_filetype()}}} will only pick
 up the first match, because of the break in the foreach loop when a match
 is confirmed ([https://core.trac.wordpress.org/browser/tags/5.0/src/wp-
 includes/functions.php#L2262 src]).

 So having e.g.

 {{{
 'txt|asc|c|cc|h|srt|vtt' => 'text/plain',

 }}}

 before
 {{{
 'vtt' => 'text/vtt',

 }}}

 will mean that the {{{.vtt}}} file type will only be expected to have the
 {{{text/plain}}} mime type, regardless of other possible matches.

 It also seems that {{{file_info()}}} is not consistent determining the
 real mime type info depending on the system setup.

 So simply assigning a file extension to multiple mime types in
 {{{wp_get_mime_types()}}} will not solve the issue here. An actual support
 for multiple mime types or mime type "fallbacks" seems to be needed.


 ----

 In the meanwhile here's a suggestion for a plugin workaround to support a
 fallback mime type of a given file extension:

 {{{
 /**
  * Support for 'text/plain' as the secondary mime type of .vtt files,
  * in addition to the default 'text/vtt' support.
  */
 add_filter( 'wp_check_filetype_and_ext', 'wpse323750_secondary_mime', 99,
 4 );

 function wpse323750_secondary_mime( $check, $file, $filename, $mimes ) {
     if ( empty( $check['ext'] ) && empty( $check['type'] ) ) {
         // Adjust to your needs!
         $secondary_mime = [ 'vtt' => 'text/plain' ];

         // Run another check, but only for our secondary mime and not on
 core mime types.
         remove_filter( 'wp_check_filetype_and_ext',
 'wpse323750_secondary_mime', 99, 4 );
         $check = wp_check_filetype_and_ext( $file, $filename,
 $secondary_mime );
         add_filter( 'wp_check_filetype_and_ext',
 'wpse323750_secondary_mime', 99, 4 );
     }
     return $check;
 }
 }}}

 and it's possible to extend this further for multiple fallbacks, see
 [https://wordpress.stackexchange.com/a/323757/26350 here].

-- 
Ticket URL: <https://core.trac.wordpress.org/ticket/45615#comment:27>
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