Alter MIME type mappings used to determine MIME type from a file extension.
This hook is run when file_mimetype_mapping() is called. It is used to allow modules to add to or modify the default mapping from file_default_mimetype_mapping().
$mapping: An array of mimetypes correlated to the extensions that relate to them. The array has 'mimetypes' and 'extensions' elements, each of which is an array.
file_default_mimetype_mapping()
Note: this list is generated by pattern matching, so it may include some functions that are not actually implementations of this hook.
function hook_file_mimetype_mapping_alter(&$mapping) {
// Add new MIME type 'drupal/info'.
$mapping['mimetypes']['example_info'] = 'drupal/info';
// Add new extension '.info' and map it to the 'drupal/info' MIME type.
$mapping['extensions']['info'] = 'example_info';
// Override existing extension mapping for '.ogg' files.
$mapping['extensions']['ogg'] = 189;
}