What are the drawbacks of using a CSV file to match file extensions with MIME types for file upload validation in PHP?

The main drawback of using a CSV file to match file extensions with MIME types for file upload validation in PHP is that it can be prone to errors and may not always provide accurate information. To solve this issue, it is recommended to use a more reliable and secure method, such as using PHP's finfo extension to determine the MIME type of a file. 

// Using finfo to validate file MIME type
$finfo = finfo_open(FILEINFO_MIME_TYPE);
$mime_type = finfo_file($finfo, $_FILES['file']['tmp_name']);

// Define an array of allowed MIME types
$allowed_mime_types = array(
    'image/jpeg',
    'image/png',
    'application/pdf'
);

// Check if the uploaded file's MIME type is in the allowed list
if (in_array($mime_type, $allowed_mime_types)) {
    // File is valid
    echo "File is valid";
} else {
    // File is invalid
    echo "File is invalid";
}

finfo_close($finfo);

Keywords

CSV file file extensions MIME types file upload validation

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