How to verify a file is a "real file" in laravel validation - php

Question

How to verify that an image is really an "Image" or a PDF is really a "PDF document" during the upload?
I observed a hack attempt to upload some files with jpg extension which has a picture preview but when I tried to open this file in an editor I saw php codes!
My concern is about:
How can I verify that a file is a real file?
Im using laravel framework, I tested with image mimes validation as shown below:
$inputs = array('image'=>$request->file('file'));
$rules = array(
'image' => 'mimes:jpeg,jpg,png,gif|required|max:10000'
);
$validator = Validator::make($inputs, $rules);
if ($validator->fails()){
die('validation failed');
}else{
die('validation Passed');
}
But this validation always pass if I try to upload the invalid jpeg file with some php injected codes!
Update:
invalid jpeg file attached

Answer 1

If you want to verify that it is an image, add the 'image' rule to your $rules array:
$rules = array(
'image' => 'image|mimes:jpeg,jpg,png,gif|required|max:10000'
);
https://laravel.com/docs/master/validation#rule-image

Answer 2

At last, i decided to check the file manually using the method -
file_get_contents(). I don't know whether this is an optimal solution. awaiting suggestions & recommendations :
public function validateFileContents($file,$needlesArray=null){
if(empty($needlesArray)){
$needlesArray = ['<?php','eval','base','gzuncomp'];
}
foreach($needlesArray as $needle){
if( strpos(file_get_contents($file),$needle) !== false) {
return false;
break;
}
}
return true;
}