如何遍历$ _FILES数组? [英] How do you loop through $_FILES array?

问题描述

这是我要循环输入的内容

Here are the inputs I want to loop through

Main photo:   <input type="file" name="image[]" />
Side photo 1: <input type="file" name="image[]" />
Side photo 2: <input type="file" name="image[]" />
Side photo 3: <input type="file" name="image[]" />

发生了一些奇怪的事情，当我没有上传任何内容时，我使用了count($_FILES['image'])，我回显了该函数，并且该函数返回值5.该数组中不应包含任何元素.当我只有4个文件开头时，为什么会有一个额外的输入?

A couple weird things happened, when I uploaded nothing I use the count($_FILES['image']), I echoed that function, and it returns a value of 5. There should be no elements in that array. Why is there one extra input when I only have 4 files to begin with?

现在有了实际的循环本身，我尝试使用foreach循环，但是它不起作用.

Now with the actually looping itself, I try using the foreach loop, but it doesn't work.

foreach($_FILES['image'] as $files){echo $files['name']; }

什么都没发生，我最终想要做的是遍历所有图像，确保它们的格式，大小正确，并对每个图像进行重命名.但是这个简单的foreach()循环表明，我什至无法循环$ _FILES数组，而当我什至没有上传任何东西时，count()说数组中有5个元素时，count()令我更加困惑.

Nothing came up, what I wanted to ultimately do is to loop through all images, make sure they are correct format, size, and rename each of them. But this simple foreach() loop shows that somehow I can't even loop through the $_FILES array and the count() confused me even more when it say that there are 5 elements in the array when I didn't even upload anything.

推荐答案

您的示例表单应该可以正常工作.只是您期望$_FILES超全局变量的结构与实际使用的字段名称使用数组结构时不同.

Your example form should work fine. It's just that you are expecting the structure of the $_FILES superglobal to be different than it actually is, when using an array structure for the field names.

此多维数组的结构如下:

The structure of this multidimensional array is as followed then:

$_FILES[fieldname] => array(
    [name] => array( /* these arrays are the size you expect */ )
    [type] => array( /* these arrays are the size you expect */ )
    [tmp_name] => array( /* these arrays are the size you expect */ )
    [error] => array( /* these arrays are the size you expect */ )
    [size] => array( /* these arrays are the size you expect */ )
);

因此count( $_FILES[ "fieldname" ] )将产生5.
但是，计算更深的尺寸也不会产生您期望的结果.例如，用count( $_FILES[ "fieldname" ][ "tmp_name" ] )计算字段总会导致文件字段数，而不是实际上传的文件数.您仍然必须遍历元素以确定是否已为特定文件字段上载了任何内容.

Therefor count( $_FILES[ "fieldname" ] ) will yield 5.
But counting deeper dimensions will also not produce the result you may expect. Counting the fields with count( $_FILES[ "fieldname" ][ "tmp_name" ] ) for instance, will always result in the number of file fields, not in the number of files that have actually been uploaded. You'd still have to loop through the elements to determine whether anything has been uploaded for a particular file field.

编辑
因此，要遍历各个字段，您将执行以下操作:

EDIT
So, to loop through the fields you would do something like the following:

// !empty( $_FILES ) is an extra safety precaution
// in case the form's enctype="multipart/form-data" attribute is missing
// or in case your form doesn't have any file field elements
if( strtolower( $_SERVER[ 'REQUEST_METHOD' ] ) == 'post' && !empty( $_FILES ) )
{
    foreach( $_FILES[ 'image' ][ 'tmp_name' ] as $index => $tmpName )
    {
        if( !empty( $_FILES[ 'image' ][ 'error' ][ $index ] ) )
        {
            // some error occured with the file in index $index
            // yield an error here
            return false; // return false also immediately perhaps??
        }

        /*
            edit: the following is not necessary actually as it is now 
            defined in the foreach statement ($index => $tmpName)

            // extract the temporary location
            $tmpName = $_FILES[ 'image' ][ 'tmp_name' ][ $index ];
        */

        // check whether it's not empty, and whether it indeed is an uploaded file
        if( !empty( $tmpName ) && is_uploaded_file( $tmpName ) )
        {
            // the path to the actual uploaded file is in $_FILES[ 'image' ][ 'tmp_name' ][ $index ]
            // do something with it:
            move_uploaded_file( $tmpName, $someDestinationPath ); // move to new location perhaps?
        }
    }
}

有关更多信息，请参见文档.

For more information see the docs.

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