What are some alternative methods or functions that can be used to check for and upload a specific file in PHP, instead of using if($_FILES["datei"]=="test.xml")?

Using if($_FILES["datei"]["name"]=="test.xml") is a more appropriate way to check for a specific file name when uploading files in PHP. This method specifically targets the "name" key in the $_FILES array, which contains the original name of the file being uploaded. By checking the file name instead of the entire file array, you can accurately determine if the uploaded file matches the desired file.

if($_FILES["datei"]["name"] == "test.xml") {
    // File upload code goes here
    move_uploaded_file($_FILES["datei"]["tmp_name"], "uploads/" . $_FILES["datei"]["name"]);
    echo "File uploaded successfully.";
} else {
    echo "Invalid file. Please upload test.xml file.";
}