上载文件时App Engine 404错误

Question

我正在通过HTML表单和PHP代码为App Engine设置新的上传文件

我已经查看了官方文档，并且还查看了Internet上的许多资源。我什么都没找到我还使用了此视频https://www.youtube.com/watch?v=_d9dugx-cHE

function upload_object($bucketName, $objectName, $source) {
    $storage = new StorageClient();
    $file = fopen($source, 'r');
    $bucket = $storage->bucket($bucketName);
    $object = $bucket->upload($file, [
        'name' => $objectName
    ]);
    printf("Uploaded %s to gs://%s/%s".PHP_EOL, basename($source), $bucketName, $objectName);
}

if(($_FILES)) {
    $file_handle = fopen($_FILES['uploaded_files']['tmp_name'], 'r');
    upload_object($bucketName.'.appspot.com', $_FILES['uploaded_files']['name'], $_FILES['uploaded_files']['tmp_name']);    
    var_dump($_FILES);
    echo '\n\n';
    var_dump($file_handle);
}

<form action="" enctype="multipart/form-data" method="post">
    Files to upload: <br>
   <input type="file" name="uploaded_files" size="40">
   <input type="submit" value="Send">
</form>

我的错误消息很长。开头为：

  

int（404）字符串（165）“ {” error“：{” errors“：[{” domain“：” global“，   “ reason”：“ notFound”，“ message”：“ Not Found”}]，“ code”：404，   “ message”：“未找到”}}