What are the best practices for handling file access in PHP scripts on a server?

When handling file access in PHP scripts on a server, it is important to ensure that proper permissions are set for the files and directories being accessed. This includes setting appropriate read, write, and execute permissions for the files and directories. Additionally, it is important to validate user input before using it to access files to prevent security vulnerabilities such as directory traversal attacks. 

// Example of validating user input before accessing a file
$filename = $_GET['filename'];

// Validate user input to prevent directory traversal
if (strpos($filename, '..') === false) {
    // Access the file if input is safe
    $file_contents = file_get_contents($filename);
    echo $file_contents;
} else {
    echo "Invalid filename";
}

Keywords

file access PHP scripts server security permissions

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