检查特定输入文件是否为空

Question

在我的表单中,我有3个用于文件上传的输入字段:

<input type=file name="cover_image">
<input type=file name="image1">
<input type=file name="image2">

如何检查是否cover_image为空 - 没有文件要上传？

Answer 1

您可以使用数组size上的字段进行检查,$_FILES如下所示:

if ($_FILES['cover_image']['size'] == 0 && $_FILES['cover_image']['error'] == 0)
{
    // cover_image is empty (and not an error)
}

(我也在error这里检查,因为0如果出现问题可能会出现这种情况.我不会用name这个检查,因为可以覆盖它)

Answer 2

方法1

if($_FILES['cover_image']['name'] == "") {
// No file was selected for upload, your (re)action goes here
}

方法2

if($_FILES['cover_image']['size'] == 0) {
// No file was selected for upload, your (re)action goes here
}

Answer 3

您可以通过执行以下操作来检查是否存在值,以及图像是否有效:

if(empty($_FILES['cover_image']['tmp_name']) || !is_uploaded_file($_FILES['cover_image']['tmp_name']))
{
   // Handle no image here...
}

Answer 4

if (empty($_FILES['cover_image']['name']))

Answer 5

简单的 ：

if($_FILES['cover_image']['error'] > 0)
    // cover_image is empty