I agree that this should be avoided at all costs but there are some cases where it might be useful.
In most cases it will just make your code unreadable and unmanageable.
Believe me, I have been down that path.
Here is an example with a use case scenario where it might still be practical.
I am extending CakePHP 3.0's File class as my default file handling class.
I wanted a to put in a static mime type guesser.
In some cases I have a filename instead of an actual file and some assumptions need to be made in this case. ( if the file exists, try to get the mime from it else use extention of filename provided)
Other times if I actually instantiated an object the default mime() method should work but if it fails the filename needs to be extracted from the object and the static method should be called instead.
To avoid confusion my aim was to get the mime type by calling the same method:
Static:
NS\File::type('path/to/file.txt')
As object
$f = new NS\File('path/to/file.txt');
$f->type();
Here is my example extended class:
<?php
namespace NS;
class File extends \Cake\Utility\File
{
public function __call($method, $args) {
return call_user_func_array([get_called_class(), 'obj'.ucfirst($method)], $args);
}
public static function __callStatic($method, $args) {
return call_user_func_array([get_called_class(), 'static'.ucfirst($method)], $args);
}
public function objType($filename=null){
$mime = false;
if(!$filename){
$mime = $this->mime();
$filename = $this->path;
}
if(!$mime){
$mime = static::getMime($filename);
}
return $mime;
}
public static function staticType($filename=null){
return static::getMime($filename);
}
public static function getMime($filename = null)
{
$mimes = [
'txt' => 'text/plain',
'htm' => 'text/html',
'html' => 'text/html',
'php' => 'text/html',
'ctp' => 'text/html',
'twig' => 'text/html',
'css' => 'text/css',
'js' => 'application/javascript',
'json' => 'application/json',
'xml' => 'application/xml',
'swf' => 'application/x-shockwave-flash',
'flv' => 'video/x-flv',
// images
'png' => 'image/png',
'jpe' => 'image/jpeg',
'jpeg' => 'image/jpeg',
'jpg' => 'image/jpeg',
'gif' => 'image/gif',
'bmp' => 'image/bmp',
'ico' => 'image/vnd.microsoft.icon',
'tiff' => 'image/tiff',
'tif' => 'image/tiff',
'svg' => 'image/svg+xml',
'svgz' => 'image/svg+xml',
// archives
'zip' => 'application/zip',
'rar' => 'application/x-rar-compressed',
'exe' => 'application/x-msdownload',
'msi' => 'application/x-msdownload',
'cab' => 'application/vnd.ms-cab-compressed',
// audio/video
'mp3' => 'audio/mpeg',
'qt' => 'video/quicktime',
'mov' => 'video/quicktime',
// adobe
'pdf' => 'application/pdf',
'psd' => 'image/vnd.adobe.photoshop',
'ai' => 'application/postscript',
'eps' => 'application/postscript',
'ps' => 'application/postscript',
// ms office
'doc' => 'application/msword',
'rtf' => 'application/rtf',
'xls' => 'application/vnd.ms-excel',
'ppt' => 'application/vnd.ms-powerpoint',
// open office
'odt' => 'application/vnd.oasis.opendocument.text',
'ods' => 'application/vnd.oasis.opendocument.spreadsheet',
];
$e = explode('.', $filename);
$ext = strtolower(array_pop($e));
if (array_key_exists($ext, $mimes)) {
$mime = $mimes[$ext];
} elseif (function_exists('finfo_open') && is_file($filename)) {
$finfo = finfo_open(FILEINFO_MIME);
$mime = finfo_file($finfo, $filename);
finfo_close($finfo);
} else {
$mime = 'application/octet-stream';
}
return $mime;
}
}