如何不上传空文件输入

Question

I have many file inputs in my HTML form. All of them are in an array.

For example :

<input type="file" name="attach[]">
<input type="file" name="attach[]">
<input type="file" name="attach[]">
<input type="file" name="attach[]">

How can I find empty inputs in PHP?

Answer 1

All the fields (even the empty ones) get sent to the server and each field will have an array entry with its information (tmp_name, name, size, error, ...) although it's empty.

Just check $_FILES['attach']['error'][$i] against the UPLOAD_ERR_NO_FILE (int: 4) constant.

For more information about file upload error messages see the official PHP manual page.

Please note that for a bunch of files with the same name <input type="file" name="attach[]"> the array will look like this (in this case for three file input fields):

$_FILES['attach'] => array(
    'name' => array(
        0 => 'File 1.jpg',
        1 => 'File 2.pdf',
        2 => ''
    ),

    'error' => array(
        0 => 0,
        1 => 0,
        2 => 4
    ),

    'tmp_name' => array(
        0 => 'foo',
        1 => 'bar',
        2 => ''
    )

    // ...
)