How to properly modify uploadable file types in WordPress

A dark truck missing a front right tire has left gouge marks in an asphalt surface, and the shredded front right tire sits on the ground beside it.

If you work with WordPress long enough, you will upload a file that is not in WordPress’ default list of allowed file types. The file will upload, vanish suddenly, and you’ll be informed:

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

Then you’ll search Google for something like “wordpress file type not permitted for security reasons” and see several blog entries from WordPress “experts” urging you to copy and paste a code snippet that leverages the upload_mimes filter into your theme’s functions.php file.

Too bad that’s poor advice. Continue reading “How to properly modify uploadable file types in WordPress”