How to Validate Only Jpeg as File Upload Extension?

Question

I’m a beginner in programming.

    public function upload(){

    if(Input::hasFile('file')){
        $novonome = uniqid() . '.jpeg';
        $file = Input::file('file');
        $file->move('uploads',$novonome);
        return 'Anexado com sucesso';
    }

    if(UploadedFile::getMaxFilesize()){
        return "Limite máximo de 2 mb";
        }  
    }

Answer 1

The validation by file extension is not safe, this link does not contain the answer to "Laravel" (although it may work) but it explains the problem that validations by extension can cause:

• Compare File Extension

The preferable is to validate via mimetype, for this use so:

if(Input::hasFile('file')){
    $file = Input::file('file');

    if($file->getMimeType() === 'image/jpeg') {
        $novonome = uniqid() . '.jpeg';

        $file->move('uploads',$novonome);

        return 'Anexado com sucesso';
    }

    return 'Só é permitido imagens JPEG';
}

the getMimeType() takes the file mimetype instead of the extension, because as I said here the extension may not be from a valid file.

You can also use the class Request + Validation, and a detail, that method you used UploadedFile::getMaxFilesize() not to validate, just to know the limit that is possible to upload varying with PHP settings, use the Validator to limit the file weight.

public function upload(Request $req)
{
    //Verifica se o campo veio vazio
    if (!$file->hasFile('file')) {
        return 'Não foi enviado a foto';
    }

    //Pega o arquivo
    $file = $request->file('file');

    $input = [
      'file' => $file
    ];


    /*
     * Regras da validação, como mimetype e tamanho máximo
     * 2048 é igual a 2mb, altere conforme a necessidade
     */
    $rules = [
      'file' => 'image|mimes:jpeg|max:2048'
    ];

    $messages = [
      'mimes' => 'Formato invalido'
    ];

    $validator = Validator::make($input, $rules, $messages);

    if ($validator->fails()) {
        return $validator->messages();
    }

    $novonome = uniqid() . '.jpeg';

    $file->move('uploads', $novonome);

    return 'Anexado com sucesso';
}

Enabling fileinfo

To enable fileinfo you need to edit php.ini and uncomment this line:

;extension=php_fileinfo.dll

Leaving so:

extension=php_fileinfo.dll

After this restart Apache or Ngnix (or whatever your server is)

Answer 2

The validation method accepts a request HTTP entry together with its validation rules, if your validation rules pass your code will be executed normally otherwise, will send an error response.

As in the code below:

$validator = Validator::make($request->all(), [
   'image' => 'mimes:jpeg'
];

    if( $validator->fails() ) {
        return $validator->messages();
    }

If the input request parameters do not pass, Laravel will automatically redirect the user to their previous position with all errors updated by session.

To show these errors in view, we can use the code below:

@if (count($errors) > 0)
    <div class="alert alert-danger">
        <ul>
            @foreach ($errors->all() as $error)
                <li>{{ $error }}</li>
            @endforeach
        </ul>
    </div>
@endif

This code will basically count the errors, in case these errors exist will show to the end user.