上传.zip文件无法使用PHP

Question

我的PHP中有一段代码处理来自HTML表单的文件上传。如果我上传图像/ txt文件，它可以完美地工作，但我想限制提交只接受zip文件，现在我的代码不起作用。任何人都可以解释为什么？我真的很难过。在下面的代码中，mkdir部分按预期工作。实际上传不起作用。

$valid_formats = array("zip", ".zip", "ZIP", ".ZIP");
$max_file_size = 1024*10000; //100 kb
$job = $_POST['pubCode'];
$client = str_replace(' ', '_', $job);
$datepickerNew = $_POST['datepickerNew'];
$foldername = $datepickerNew . '_' . $client;
$directoryLocation = 'uploads/' . $datepickerNew . '_' . $client . '/';

mkdir('uploads/' . $foldername);
$path = $directoryLocation; // Upload directory
$count = 0;

if(isset($_POST) and $_SERVER['REQUEST_METHOD'] == "POST"){
    // Loop $_FILES to exeicute all files
    foreach ($_FILES['files']['name'] as $f => $name) {     
        if ($_FILES['files']['error'][$f] == 4) {
            continue; // Skip file if any error found
        }          
        if ($_FILES['files']['error'][$f] == 0) {              
            if ($_FILES['files']['size'][$f] > $max_file_size) {
                $message = "$name is too large!.";
                continue; // Skip large files
            }
            elseif( ! in_array(pathinfo($name, PATHINFO_EXTENSION), $valid_formats) ){
                $message = "$name is not a valid format";
                continue; // Skip invalid file formats
            }
            else{ // No errors found! Move uploaded files 
                $newName = str_replace(' ', '_', $name); 
                if(move_uploaded_file($_FILES["files"]["tmp_name"][$f], $path.$newName))
                $message = "File has been uploaded";
                $count++; // Number of successfully uploaded file
            }
        }
    }
}