What is the best way to validate Spreadsheet files (xls, xlsx and csv) in Laravel?

Hey you all,

I am working on an application which processes spreadsheets in the following formats: XLS, XLSX and CSV. I want to validate the file that the user selects to upload. I followed Laravel's documentation that says:

Even though you only need to specify the extensions, this rule actually validates against the MIME type of the file by reading the file's contents and guessing its MIME type. A full listing of MIME types and their corresponding extensions may be found at the following location: http://svn.apache.org/repos/asf/httpd/httpd/trunk/docs/conf/mime.types

So I went to that link and I found the following MIME types:

MIME type (lowercased)          Extensions
============================================    ==========
application/vnd.ms-excel            xls xlm xla xlc xlt xlw
application/vnd.openxmlformats-officedocument.spreadsheetml.sheet   xlsx
text/csv                    csv

I tried with all of them in my code, like:

        $this->validate($request,[
            'version' => 'required',
            'file' => 'required | mimes:application/vnd.ms-excel', 
            ]);

        $file = $request->file('file');

        if (!($file->isValid()))
        {
            $error = $file->getErrorsuccess();
            return view('spreadsheet/create')->with('error',$error);
        }

Besides the MIME types listed on apache's website I also tried with simply 'xls, xlsx, csv' but it didn't work either.

It fails for all the three file extensions and I tried with different files.

How am I supposed to validate those kinds of files? I did a test with png and it worked fine.