public function guessExtension()
    {
        $extension = null;
        if ($this->hasFile()) {
            $extension = $this->file->guessExtension();
        } elseif ($this->hasKey()) {
            $extension = pathinfo($this->getKey(), PATHINFO_EXTENSION);
        } elseif ($this->hasPath()) {
            $extension = pathinfo($this->getPath(), PATHINFO_EXTENSION);
        }
        $extension = strtolower($extension);
        return $extension;
    }
public function guessExtension()
    {
        $extension = null;
        if ($this->hasFile()) {
            $extension = $this->file->guessExtension();
        } elseif ($this->hasKey()) {
            $extension = pathinfo($this->getKey(), PATHINFO_EXTENSION);
        } elseif ($this->hasPath()) {
            $extension = pathinfo($this->getPath(), PATHINFO_EXTENSION);
        }
        $extension = strtolower($extension);
        return $extension;
    }
public function guessExtension ( ) { $ extension = null ; if ( $ this -> hasFile ( ) ) { $ extension = $ this -> file -> guessExtension ( ) ; } elseif ( $ this -> hasKey ( ) ) { $ extension = pathinfo ( $ this -> getKey ( ) , PATHINFO_EXTENSION ) ; } elseif ( $ this -> hasPath ( ) ) { $ extension = pathinfo ( $ this -> getPath ( ) , PATHINFO_EXTENSION ) ; } $ extension = strtolower ( $ extension ) ; return $ extension ; }
Guess file extension.

@return string
Guess file extension .