'text/plain',            'htm' => 'text/html',            'html' => 'text/html',            'php' => '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',        );        $ext = strtolower(array_pop(explode('.',$filename)));        if (array_key_exists($ext, $mime_types)) {            return $mime_types[$ext];        }        elseif (function_exists('finfo_open')) {            $finfo = finfo_open(FILEINFO_MIME);            $mimetype = finfo_file($finfo, $filename);            finfo_close($finfo);            return $mimetype;        }        else {            return 'application/octet-stream';        }    }}?>

http://php.net/manual/en/function.mime-content-type.php