How do I determine the extension(s) associated with a MIME type in PHP?

Question

Is there a quick and dirty mapping of MIME types to extensions in PHP that I can make use of?

Answer 1

Not built-in, but it's not terribly hard to roll your own:

function system_extension_mime_types() {     # Returns the system MIME type mapping of extensions to MIME types, as defined in /etc/mime.types.     $out = array();     $file = fopen('/etc/mime.types', 'r');     while(($line = fgets($file)) !== false) {         $line = trim(preg_replace('/#.*/', '', $line));         if(!$line)             continue;         $parts = preg_split('/\s+/', $line);         if(count($parts) == 1)             continue;         $type = array_shift($parts);         foreach($parts as $part)             $out[$part] = $type;     }     fclose($file);     return $out; }  function system_extension_mime_type($file) {     # Returns the system MIME type (as defined in /etc/mime.types) for the filename specified.     #     # $file - the filename to examine     static $types;     if(!isset($types))         $types = system_extension_mime_types();     $ext = pathinfo($file, PATHINFO_EXTENSION);     if(!$ext)         $ext = $file;     $ext = strtolower($ext);     return isset($types[$ext]) ? $types[$ext] : null; }  function system_mime_type_extensions() {     # Returns the system MIME type mapping of MIME types to extensions, as defined in /etc/mime.types (considering the first     # extension listed to be canonical).     $out = array();     $file = fopen('/etc/mime.types', 'r');     while(($line = fgets($file)) !== false) {         $line = trim(preg_replace('/#.*/', '', $line));         if(!$line)             continue;         $parts = preg_split('/\s+/', $line);         if(count($parts) == 1)             continue;         $type = array_shift($parts);         if(!isset($out[$type]))             $out[$type] = array_shift($parts);     }     fclose($file);     return $out; }  function system_mime_type_extension($type) {     # Returns the canonical file extension for the MIME type specified, as defined in /etc/mime.types (considering the first     # extension listed to be canonical).     #     # $type - the MIME type     static $exts;     if(!isset($exts))         $exts = system_mime_type_extensions();     return isset($exts[$type]) ? $exts[$type] : null; } 

Answer 2

You could use mime_content_type but it is deprecated. Use fileinfo instead:

function getMimeType($filename) {     $finfo = finfo_open(FILEINFO_MIME_TYPE);     $mime = finfo_file($finfo, $filename);     finfo_close($finfo);     return $mime; }